growing cannabis on coir

How to grow cannabis plants in coco coir

Coco coir as substrate for plants

In this post we’ll explain how to properly use coco coir as a substrate for our cannabis plants. After years of experience with this growing medium, we believe that coco coir is the easiest choice among hydroponic substrates.

To get the most out of it, first of all we should take a closer look at its composition and properties.

Coco coir for hydroponic cultivation

Coco coir is an organic product that comes from the fruits of coconut trees. After processing the coconuts, the remaining fibres of the husk or mesocarp are collected as waste material. These residual fibers are in the form of powder and filaments, and the mixture of both is an ideal substrate for ornamental plants or intensive hydroponic cultivation.

If we take into account the advantages of coco coir when compared to soil, we’ll soon understand why so many growers are considering growing their plants in coco. It’s important to highlight the differences between coco coir and other substrates to understand the great results obtained with this growing medium.
Firstly, it should be stressed that coco coir is an inert substrate. This means that it doesn’t contain nutrients, so we must fertilise whenever we water the plants.

The aeration capacity of coco coir is one of this substrate’s strong points. It’s an extremely soft growing medium, which enables the root system of the plants to develop much faster than in soil. A stronger root ball means more vigorous growth, which allows a reduction in the vegetative period. Also worth mentioning is that coco coir contains natural Trichoderma, beneficial fungi which enhances the development of roots and improves the plant’s immune system, creating a colony of microbial life that greatly enhances the metabolic processes of the plant.

Watering cannabis plants in coco coir

Chronic plant in 1.65 L pot with coco coir

As we have mentioned before, coco coir contains no nutrients, so we must add fertiliser every time we water our plants. In this way, checking and adjusting the EC and pH levels of the nutrient solution is crucial to obtain good results.

The EC or electrical conductivity tells us the amount of salts – nutrients – contained in an aqueous solution. We must control the amount of nutrients contained in the nutrient solution by adding more or less fertiliser, always taking into account the needs of the plants, which mainly depend on the life stage. The pH level indicates if our nutrient solution is alkaline or acidic. pH is measured using a scale from 0.0 to 14, being “0” acidic, “7” neutral and “14” alkaline.

Plants grown in coco coir need a pH level ranging from 5.5 to 6.3, depending on the life stage of the plants. Normally, pH is adjusted to 5.5 – 5.8 during growth and 6.0 – 6.3 during bloom, which helps the plant to assimilate the most demanded nutrients at each stage.

The fertilisers used should be suitable for this substrate, with chelated forms working best. There are plenty of brands on the market which formulate specific fertilisers for cultivation in coco coir, so you can choose from a very wide range of products especially developed for hydroponic cultivation, both organic and mineral.

AK-47 from Serious Seeds

Mineral fertilisers are the most widely used as they are made specially for hydroponic growing systems. It should be noted that there are also fertiliser brands focused on producing nutrients from organic guano to be used with coco coir, offering new possibilities to those who miss the flavor of organic buds grown in soil.

The containers or plant pots used with coco coir must have a good drainage system as the ability to drain excess water quickly and easily is crucial for proper nutrient uptake and to avoid rot root.

Plants grown in coco coir need less amount of substrate that a plant grown in soil would require. We can use a pot of 1.65l with coco coir to get the same results than a 7L pot with soil. For larger plants, we can use 3L pots with coco instead of 11L containers with soil.

Irrigations during the first weeks should be moderate, with an initial amount of no more than 100ml per plant. This facilitates the dry/wet cycle of the substrate, thus enhancing root development. As the plants grow taller, gradually increase the amount of nutrient solution. You can also install an automatic irrigation system that will increase yields and improve efficiency.

When and how to flush the roots in coco coir

Salt excess in coco coir

Another important aspect in regard with irrigation and fertilising is root flushing, as well as nutrient excesses and deficiencies. As happens with any other vegetable, if we overfeed the plant we will compromise nutrient uptake and cause a general nutrient lockout that will probably lead our plants to death. Thus, it’s always appropriate and necessary to check both the EC of the nutrient solution and the EC of the drainage water.

Measuring the EC in this way allows us to know the level of salts in the substrate. These accumulated salts raise the nutrient concentration in the substrate, often causing an excess of fertiliser. As we mentioned, we may see deficiencies usually accompanied by general nutrient lockout, which means that the plant can’t properly assimilate nutrients.

We should always flush the substrate when the EC levels of the drainage water are higher than 2.5, using some enzyme supplement and watering the plants with triple the amount of water than the volume of the pot. Also, adjust the pH level according to the life stage of the plant and use the lowest possible EC. Flushing the substrate reduces the concentration of nutrients in the substrate and thus avoids nutrient imbalances. Most hydroponic growers flush their plants with enzymes every 15 days.

Nutrients and additives for coco coir

  • Canna Coco A + B
  • Cannaboost
  • Canna Rizhotonic
  • CannaZym
  • Canna PK13-14
  • Canna Flush

  • Hesi growth complex for soil and coco
  • Hesi coco growth and flowering
  • Hesi root complex
  • Hesi PK 13-14
  • Power Zyme
  • Super Vit

  • H&G Coco A + B
  • H&G Roots Excelulator
  • Top Shooter
  • H&G Top Booster
  • H&G Bud XL
  • H&G Shooting powder
  • H&G Multienzyme
  • H&G Drip Clean

  • Solotek Grow
  • Solotek Bloom
  • Vegetative Grow Booster
  • Vitamax plus
  • Monster Grow
  • Monster Bloom
  • Bloom Fuel
  • Blossom Blaster
  • Heavy Bloom
  • Pro Silicate
  • Final Flush

  • Root Max Root Stimulator
  • Booster Max Growth Stimulator
  • Flora Max Bloom Stimulator
  • Bio Protector

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Comments in “How to grow cannabis plants in coco coir” (20)

Crip 2020-01-10
Hey thanks for the reply and happy new year to all of you. Im doing fine and hope you too :). Ok i think with two weeks of flushing should be fine if next grow doesn’t show me those problems. I did mold tests in the grow room and some rooms of my house and the chart from the mold test said i have perfect air without any hidden mold problems. I also have a bacteria test for the water that i will test the next days with my osmosis water. But i don’t think it is contaminated and all the problems have more to do with my techniques and maybe my environment. My humidity is so god damn low at the plants tops its only 25% and at the bottom its around 35-40%. So for my next grow i will get a GSE humidity/temperature controller that i will plug to the exhaust ventilaton and i also get a humidifier to bring the humidity in perfect conditions. I read that low humidity will force the plants to uptake more water and also nutrients so if its too dry i would need lower amounts of nutrients or they burn way faster than plants with an ideal environment. I also think that could be the problems i always get. I lowered the nutrients to a point where they got a calcium deficiency but the darker leafs didn’t go away and maybe because of the low humidity they get N toxic but if i go down with the strength they show me the calcium deficiency because with the lower strength there isn’t enough calcium in it and i would need to apply a calmag product. I think it’s the best to optimize the environment and do another grow to find out if that solve the problem or if it continues it must be something else. I try to bring everything in perfect condition so im sure its not an environmental issue. The weird thing is with soil i never had any dramatic problems but i didn’t grow in the growbox i have now. I did grow in a normal room where i hang the lamps and added a small exhaust, i used biobizz light/allmix and their fertilizers so everything was bio and i read its harder to overfeed with biofertilizers. I got the growbox as a set with 2x600watt and a exhaust with 1100m3/h and i think that the exhaust is waay to huge and that’s also causing the low humidity plus the hps lamps dry out the air. And if i would buy another exhaust that is not as powerful as the one i have right now i maybe get too high humidity in late flower and the best option is just to buy a controller for the exhaust and maybe a humidifier, a dehumidifier should not be needed with the controller where i can set the humidity for each stage and my exhaust will easily dry the air down if needed :’D. And all the problems i have with coco i don’t know why that didn’t happen with biobizz but I think the big room i did grow the plants in Biobizz just had a good environment and in a bigger room the humidity and temperature are more stable than in the growbox i use now. I also wrote with many guys on the internet and they never had those weird problems with advanced nutrients but there environment were in perfect conditions. Do you think that the growbox set i bought has a exhaust that is way too powerful? The temperature in the growbox are pretty good. Around 25°C but the low humidity isn’t ideal. I don’t know how powerful the exhaust should be so i bought a set on the internet from a grow shop. If i would have the old room again would be the best option but can’t take the room again and needed the growbox i have right now. I also found that the biobizz soil had a way more fluffy structure than the coco i use right now and i watered in soil after the first centimeters of the top were dry. Coco feels way more spongy and holds more water than the biobizz soils but im maybe wrong what im saying. The one plant i took out of the growbox at the beginning of the the flowering had poor developed roots but the other plants in the growbox have the coco completely outgrown and there are more roots than coco 😀 the roots looking white thick n healthy so it should be not a watering problem. I need to water one time per day or the coco is completely dry the next day and i use 7L pots. I don’t think i will use bigger pots next grow but maybe get some airpots for the plants and if the temperature and humidity are under control the airpots would also help to bring more oxygen into the rootzone/coco.

Crip 2020-01-08
Hey i didn’t add all the”. “. They came from the smiles i added and show as”. ” here hmm. I stop adding the smiles

Crip 2020-01-08
Hey my grow is nearly finished but i couldn’t fix the problem. I think it had to do with nitrogen overfeeding because the buds are really leafy and the nitrogen in the grow fertilizer is made of urea, ammonium and nitrate and i read that urea is slow releasing and bacteria have to make them available for plants to eat and also the ammonium needs bacteria because they turn the ammonium into nitrates. Maybe i gave them too much of the grow fertilizer and will try some other plants next grow again with the Advanced nutrients fertilizer and the rest i use the Canna fertilizer for coco. The bloom fertilizer also contains urea and nitrate and maybe i also used there too much because the symptoms like leafy buds, long stretched stalks and also the weird leaf colors with the brown spots from the edges that started to grow and the leafs died looked like some sort of Nitrogen toxicity, the leafs didn’t look too dark like some pictures if i google it but they were not a healthy green color more in between of healthy green and too dark . i did the flush and the runoff was really dark brown colored but the ec was never over 2.5ec but after the flush i only gave them around 0.8ec of the blood fertilizer and added a late bloom booster 1.5.4 npk to bring the ec up to 1.2 and the buds started to get bigger . I think the fertilizer can be really good but you really need to take a look how the plants look like. In my grow i just should have flushed way earlier and also take the plants out of the box under normal light to see how dark the leafs look like. And next time i will take them one time in a week out to see the color and do change the strength if they look to pale or dark. I will only go around 1.0ec in the grow stage and take a closer look at the color and if they look fine i use the right concentration. In flower i will use also around 1.0ec of the bloom fertilizer and if advanced nutrients says to add the pk booster and the late flower booster i will bring my ec higher with the pk boosters around 1.5maximum but also take the plants out of the box and always take a close look if some burning tips occurred after i added the pk booster and also take a look at the color and drop the bloom fertilizer if they get too dark in late flower. The nutrients didn’t smell bad after i cut out the grow boosters and they were maybe gone bad. I will use your canna feeding chart for coco but have some questions about it. 1. You say 1ml/l canna a/b for germination, i will germinate ny seeds in a peat moss plugs and after the roots lookin out of the plugs i transplant them into the coco and add 1ml/l of the canna fertilizer. Is this ok and if i would germinate the seeds in the coco and add 1ml of the canna fertilizer does the seeds getting not damaged by the fertilizer? I always read that can damage the seeds . 2. Should i add to the fertilizer tap water? Around 0.3ec tap water would contain 50mg calcium because our tap water contains 100mg calcium at an ec around 0.6 so half of that would give me 50mg calcium. Or should i add 0.3-0.4ec calmag? I only have one calmag product from general hydroponics with an 4/1 calcium to Magnesium ratio and im not sure if that ratio will leave to a magnesium lockout later in the grow stage after i also add the canna fertilizer. Do you know a good calmag product or should i get a mono calcium and mono magnesium product from canna to add the right calmag ratio like you said on your website? 3. The last question is also about your feeding chart. You say to flush one week with a flushing solution and then two weeks only water so you would flush plus water for three weeks? Or do i understand that wrong? I never gave my plants so long water only so i ask about it and maybe i will also use around one week with a flush solution and two more weeks only water in my next grow if that gives a better tasting flower at the harvest time ?? Greetz Crip

Tim Alchimia 2020-01-10
Hey Crip! Happy new year, I hope you’re well. Apologies for slacking off on the comments over the holidays. It’s great to hear that your latest harvest is nearly ready but I’m sorry that the problem didn’t get solved. As you say, it’s all about reading the plants and trying to understand what they’re telling you. And as Canna say on their nutrient schedules: “The guidelines in the table are not an iron law, but can help novice growers develop a sophisticated fertilisation strategy. The optimum fertilisation strategy is further determined by factors such as temperature, humidity, plant species, root volume, moisture percentage in substrate, water dosage strategy, etc.” I couldn’t have put it better myself! I hope that helps, speak soon. All the best and happy growing! Let me try and answer your questions: 1. In soil I wouldn’t normally feed germinating seeds until I saw the first set of true leaves appear, but since this is inert coco I think I’d be inclined to follow the chart and give 1ml/l along with Rhizotonic. You could always apply it at half-strength to be on the safe side. tbh that’s probably what I’d do in your situation, especially as you don’t want to go over 1.0 EC in veg growth. 2. Our chart doesn’t specify but on the accompanying official Canna chart it talks about using water with EC of 0.4 and pH ranging from 5.5 to 6.2 but gives no mention of CalMag, so I’d have to say that using the tap water would probably be ok in this case and that adding CalMag would be unnecessary (Canna do make a CalMag Agent that they say is for use with reverse osmosis or soft water though). 3. Yes, the feeding chart has a 3 week flushing period, but I’d say that 2 weeks would be enough. That said, the full 3 weeks would certainly make for a really clean tasting harvest, I just don’t know how yields might be affected.

Crip 2019-12-15
I forgot something to ask. The canna fertilizer says to use tap water between 0.2-0.4 ec. Should I use around 0.3ec that would be around 50mg/ppm of calcium in the water or is that too much? And the feeding schedule the ec is only the fertilizer ec without the tapwater ec right? So i would use 0.3ec tap/osmosis water and your feeding schedule from canna coco. The canna fertilizer will expire in 2022 ? can’t understand why AN doesn’t write any expiration date on the fertilizer.. The fertilizer is maybe over 5years old or longer.. If they don’t have an expiration date they should write when the fertilizer was made ?? The b52 was 100% for the really bad smell responsible. But the solution has still some weird smell and the AN sensi coco has also organic wetting agent in it and that maybe cause the other smells. And the part a fertilizer is brown like the b52 was and first what i noticed was the watering can has some brown stuff building up in it and that could be the stuff from the part A fertilizer that was falling out of the solution after some time. First the solution starts to get cloudy and then the solution/water has that gluey mass floating on the solution. I shouldn’t change the solution and just let it stand some more days to see if that stuff getting worse or if some things would have happened after some days. I read that growers also had the same issues and they said its bacterial growth in the solution causing the smell and the gluey/cloudy solution. But the only way would be to send a water test to a company that will give me a analysis how much microbes are in the water. But i will see if the canna fertilizer will change that. I had a friend that also had those problems years ago and he used always canna fertilizers but had the 5L bottles from canna that stand for really long time open. I think its also better to calculate how much fertilizer is needed for one or maybe two grows and only buy that amount of fertilizer so the fertilizer don’t stay open for a long time because you can’t use all the fertilizer in a year ? Greetz ✌️✌️

Crip 2019-12-15
Hi thanks for the reply ☺️ i did test it again and it has still some weird smell. Maybe the brown leftover in the watering can comes from the nutrients. Ok i could get some water tests for around 40€ but this is only a hometest “water test agar plate” (don’t know if i spell it right) and there you can see if some bacteria/microbes start to grow and if many dots start to grow in the test the more contaminated would be the water. The normal analysis would cost minimum 200€ ? I upped the nutrients and first it stopped but now the leafs started to die again ? I will do the test with the canna coco fertilizer today and the AN and hopefully it stops ☺️ and before i buy the water test i should first try it with the different fertilizer and see what happens. Is it a problem if i switch from AN to canna in the flowing stage? I would use some more drainage or a flush before i use a different fertilizer to get all the other fertilizer out of the coco. A few weeks ago where i did the test i had one time the fertilizer didn’t start to smell but i covered the can so no dust can get into the solution and our house is always pretty dusty, don’t know why ? I will use the canna fertilizer today and also the testing solution to see what happens in one or two days. And the osmosis system should work without any problems. The ec from the tap water is 0.5-0.6/250-300ppm and the osmosis water ec is 5ppm. I will write back in some days ✌️✌️ Greetz

Crip 2019-12-11
Thanks for the good informations ☺️ one plant were only half the size as the other plants and that had some brown roots at the bottom. I took all others out of the pots yesterday and they lookin good nice white roots completely filled out the 7l pots. The small plant also had not enough space so i placed that plant at the outer space of the box and the 600watt didn’t gave that plant much light so i took her out to be safe that this plant doesn’t infect the healthier plants. I did feed yesterday at the evening to see if watered too often but in the evening all big plants had pretty dry coco so i can be sure they were not watered too often because normal i feed around 14.00/2.0pm and yesterday i fed at 18/6pm so only 4 hours later the pots were really dry. I think i will give them a feed in the morning and see in the evening how much they dried down and maybe give them a small amount so that they have enough moisture over night. The moisture meter and the drainage tables should come in some days also the air pots. Ok i will flush the plants every two weeks next grow after i installed the drain tables so i don’t have to take every single plant out of the box. And the coco yesterday evening the bottom didn’t felt soggy so maybe i should not increase the feedings and always water until the coco did dry at the bottom more and only use a small amount sometimes in the evening if needed when they getting to dry for the next day so i can keep them moist over night and next day they should be good for feeding with some runoff and i will always take a look if they will dry out over night and just add a little to keep it moist. I think next grow will be way easier with a table that drains the water easily plus the airpots. And with the moisture meter i can always take a look how wet/dry they are and maybe i will buy a watering system after i know how fast they dry with the airpots and the moisture meter gives me good information in each stage how often to feed automatically so the coco isn’t too wet and also not too dry. I will everything write in my book how often to feed in each stage and also how long the automatic watering system should be turned on to get a small amount of runoff each time ☺️ but that system i will buy in 3 months or so and see how it works with handwatering the airpots and maybe i will also use the pots i have right now to see some differences.. And i did mix two days ago 10l of nutrients in the evening so i can water right next day and don’t have to worry about mixing in the morning. Mixed part a stir the water well around 15-30 seconds so everything dissolves and same with part B and the pk booster let it stand and stir one more time, added the air stone and the watering can stand outside of the box in the dark, added a aqua heater to keep the solution around 18-20°C. Next day i was on the way to feed the plants, cleaned the room and i had some really bad smell ? i took a sniff at the solution and it stinks again like some things rots. I didn’t used the solution and made a new batch and feeded in the evening this day. I started to feed the plants in the evening and the solution that stand near the box got even worse in the smell ? the water turned also some cloudy. That was yesterday, i just let the solution stand maybe i will find out what is growing in the solution after some days and how the water will look like and smell ? I have some h2o2 and will add that to a different watering can to see if some bad bacteria are inside my water or if something in the nutrient just fall out and start to rot. I read that the fertilizer with no expire date will last very long without going bad.. Some said only two years, some others said you don’t know how long that nutrients stand in a shop before and if no one using it the fertilizer could be more than three years old but unopened and maybe will go bad pretty quickly after opening the bottles ? i also noticed that some stuff is floating in the solution like some nutrients didn’t dissolve.. So i tried to read about rotting/bad smell from the solution and i found an article where a guy also used some fertilizer without an expiration date and he had also a rotting smell and it was because of the nutrient where nobody knows how long they were stored before they got opened. He got some new fertilizer and the problem was gone. So i will test it with a new solution today and see what happens and another one with h2o2 to kill off the bad bacteria if there are some. I thought the best would be send samples of the osmosis and tap water to a laboratory and check for microbe content and maybe heavy metal and some other stuff so i can be safe if i get the tests and see what is in it and also if the osmosis water is free of pathogens. If some bacteria are in the water i would buy a heater get a big reservoir where i let the osmosis water in it and boil it so long until the bacteria are dead depending on which pathogen but you can find for each pathogen how to kill them. Or using h202 but i can’t add root supplements, enzymes and good fungi and bacteria o boiling the water for some minutes would be a better option and in the long run its cheaper because those h202 bottles also cost a good amount of money and a 1l h202 only holds for one or two grows depending on the strength and i only used the 3%h202 3ml/l and this h202 did cost a good amount because i don’t want bad chemicals that is mixed in the h202, costs less but that stuff you will never know what ingredients could damage your plants or starts to build up in the plants and leaving something toxic in it ? I bought some canna coco fertilizer and will test it also if this solution starts to smell, i did disinfect the watering can and the airstones every 10days or so and after each watering i flushed the leftover nutrient with some osmosis water, so every after watering i flushed the cans and after ten days i flushed it with osmosis first and added some h202 to the osmosis water and let the stones soak and the cans i washed with a towel, so that should not be the problem causing the rotten smell again ? i need to do some more testings now and if i can’t fix it the water analysis will give me a better understanding and i will see what’s in it. Costs also much money. But i think if i will get the growing area near ideal conditions like temperatures and humidity than the drain tables are also a must because the drain can run into a tank and i just need to throw the drainage away without making a huge mess that turns the area into a dirty room and that will also inhibit bacteria/fungi if i don’t have to take every plant out of the box turn them back into and so i don’t touch the growbox ground with my shoes. Also with the moisture meter that will help me alot if i can’t take out the pots next grow if they stand on the draintable or to determine my plants pots right now where the plants weight more than the pots ? in the beginning its not a problem but in flower taking always that big plants out and one mistake and a branch is broken ?, the water analysis costs some money also but the water is so important and if im not sure if it’s the nutrient or the water i need to test it. In this time i can start some seedlings and try my best to get the fastest healthiest plants in coco and in around a half a year i have the most things needed to be set up and also have a better feeling on the watering techniques in coco and then i will get the automatic system. I will grow for the next few years only coco to get everything dialed in and maybe after that time i could try some hydroponic systems. ? Sounds crazy but i like growing and get problems fixed no matter how long i need to find the problems. And a perfectly dialed in area is important so im sure its not my environment in the box ☺️ I did a mix yesterday with h2o2 and all the same nutes, the smell is the same only not soo strong, but something looks like it falls out, i checked the water that has the smell since yesterday and there you can clearly see some of the nutrient are falling out of solution and if some nutes are gone bad that could also lead to the smell. I will throw the mixture away/clean the cans and mix only the main fertilizer to see if the pk booster got bad and the other mixture i add the h2o2 again. And a mix with the canna coco fertilizers, though about to take the AN stuff on side or throw it away and feed with the canna coco fertilizer but im not sure if the plants like that. I could also mix the osmosis water with tap water to get around 0.3ec,the tap water has 0.6ec and there are 100mg calcium in it and im not sure if the 0.3ec with 50mg calcium is too much ? next grow is definitely with canna coco fertilizer and the coco and i use your feeding charts ? greetz maybe i will write more later or tomorrow and thanks for your kind words and the help/tips you give me ☺️ ✌️✌️

Tim Alchimia 2019-12-13
Hey Crip, good to hear from you mate! I’ve been investigating RO filters a little, and from what I’ve read, if the filter is working as it should there’s no way the water can have any microbes in it at all. The filter is fine enough to remove chemical molecules from the water, and with bacteria, fungi and viruses being many times larger, they too are removed. So, with this in mind, and taking into account that: a. we don’t know the age of the fertilisers, and b. they seem to be coming out of solution, with floating lumps etc, suggesting that they aren’t in the best condition, I would surmise that the problem is the nutrients and that an expensive water test is not necessary! (And that probably goes for the H2O2 as well, I’d say you could probably leave that out of the equation as well unless for some reason you need to mix a nutrient solution and leave it for longer than normal.) Hopefully, you’ll quickly see an improvement after you change to the Canna Coco nutrients. I think that the root of the problem is most probably related to the condition of the nutrients and that once you’ve got the growing conditions dialled in as you’d like, you won’t have anywhere near as many problems. It’s likely that the problem originated from using a nutrient line that, from what you told me, isn’t too popular in your area, and may well have been sitting on the shelf for a long time before you bought it. I’m sure that by switching to a more popular brand you’ll be assured fresh product every time. Let us know how you get on with all this, please. Best of luck, happy growing!

Crip 2019-12-08
Hi today i found some mold spores sitting in the coco pots where the drainholes are ?? that was the exact same problem like i last time had. So i think its some sort of fungi infection in the plants. Don’t know which one and can’t test it in Germany because it is illegal ?? i would pay everything to find out what mold it is so i could find out what’s causing it. I will buy some flood/drain tables next grow and also use airpots ti get more oxygen in the root zone and the pots also look like they drain better. So maybe i also watered too often again but the pots really felt light and the cocos color did change from blackbrown to a light brown ?? the plants are pretty heavy because they are around 80cms in height so its not easy to say if the coco is still too heavy/moist or not ? I also used good bacteria and fungi supplements from advanced nutrients but they didn’t help so i think i will not use them again they cost so much money ? I should have used some clay pebbles at the bottom for better drainage i think but my pots have really much drain holes but like i said some posts before it feels like the coco is really muddy/wet at the bottom but at the top of the pits it has a good structure and didn’t look like mud and doesn’t looked wet ? maybe the fine coco particles got to the bottom after several waterings and that caused the problems. I will water even more slowly next grow to avoid swamping the pots because that also could lead to compression in the bottom i think. I also used new coco. And at the seedlings/growth stage the coco i used didn’t felt heavy in the bags. I didn’t had enough coco and had to buy a new bag. This bag felt really heavy and i think it was soaked with water because it was stored outside ? i always buy from the internet because no grow shop is in the near. And maybe some mold was inside the coco because they stored it incorrectly.. So many things i have to figure out what is causing the issues ? 1. Bad stored coco -> i will use the coco blocks next time. 2. Mold spores in the air taking hold in the coco because they have water/nutrients/organic material to thrive in it -> Some ventilation and a hepa filter would stop the spores vut would cost some money. 3. Watering too fast so the coco got compacted over time leading to the wet coco at the bottom. Watered too often causing the coco stay wet for to long -> watering slowly next time and buy a tensiometer to find out how much moisture is left. 4. Drainage issues -> using clay pebbles at the bottom, get some airpots because they look like they have some mesh at the bottom where the water can drain more easily. Getting some flood/drain tables so the runoff can drain without any problems because i put the pots always out of the tent and put them on a grud that were attached to a bucket where they sit on until it stopped draining but still some water drained in the floor, i let them sit on the grid for around 15mins until it stopped draining to be safe there’s no excess water coming out of the pits but still a little drain was always on the floor and that could lead to a over saturated coco because it sucks in the little drain water left on the ground. I thought it would be easier to grow in coco than in soil ? missed hard ? never had those issues there and i also find it easier to know when to water normal soil as coco coir because it get lighter in weight but still has enough moisture and the texture of the coco seems really fine not like some good soils i find but i could be wrong. And i will get it fixed next time and use some moisture meter and flood/drain table and some airports or clay pebbles at the bottom to be safe. I think the problem is caused by the wet coco bag i got oor im watering too fast so the fine particles will compress the coco at the bottom and the coco loose the structure, like i said it feels airy nit compressed at the top but the bottom looks way too wet/soggy and so the coco lost the structure because of watering too fast. I read many people swamp the coco but i only used small amounts of water and let it soak up and repeated this until i got some runoff but i didn’t swamp it. And the runoff readings were always ok i think. Ph was in the sweet spot and the ec never got higher than 1.6 in the runoff. Next time i will find out how much moisture it holds with a tensiometer but im not sure if a tensiometer that is used in normal soil will work for coco and can’t find informations on the internet. Greetz and i will given feedback again also in my next grow. You can delete the other messages if you want ? the page got really long because of all my messages ??✌️✌️✌️

Tim Alchimia 2019-12-10
Hey Crip, great to hear from you! My sincere apologies for not replying sooner. I’ve been asking a few of my coco grower friends their opinion about this and the general consensus is that you’ve been letting the substrate stay too wet at the bottom of the containers, which could have led to some kind of fungal problem with the roots down there. I see the low EC in the runoff has corrected itself naturally, but that could also have been caused by irrigating too frequently, so we think that reducing the frequency of the irrigations would be a good start. The roots thrive when coco is almost dry, but it loses humidity really fast, so it’s a matter of hours before the plants will die. So it’s better to keep it moistened but never too wet. In our experience, at least with coco, the rule of “let the substrate dry between irrigations” doesn’t work that well, the roots will develop better when the substrate is constantly moist. A tensiometer will help with this, and from what I’ve read they work in coco as well as in soil, although there’s a learning curve involved. As for putting some kind of drainage at the base of the pots, such as clay balls, the consensus is mixed, with some growers doing this religiously while others find it’s too much work and isn’t worth the bother. I also remember reading that in some cases the clay balls can have the opposite effect, causing water surface tension to build up between the substrate and the drainage, which actually hinders free drainage. For this reason, I stopped using clay balls in my soil pots a few years ago. I’d rather fill that space with substrate that the roots can actually use! On the other hand, I think your plan to get a flood and drain table would do a great deal of good for the health of the roots, good idea! The air-pots you mention, if they’re the semi-rigid plastic ones with lots of holes in them, ae absolutely fantastic in my opinion. I use 15-litre versions outdoors in early summer to get my plants to a decent size before they go into the ground. I get the most vigorous growth in those containers, no doubt. Having said that, when I did a side-by-side comparison with fabric Smart Pots I got noticeably heavier yields in the fabric pots than in the plastic air pots. I think that either of those options would greatly improve any drainage issues and increase aeration of the root zone, all to the benefit of the plants’ health. If you combine this with your plan to add perlite mixed in with the coco, then I really think you’re going to have super healthy roots! As you mention, the texture of the coco is crucial and if it’s too fine then it can become compacted, seriously affecting aeration. As for flushing the coco, again, opinions are divided. Some say flush every week, some say every two weeks, others say every month while some say not to flush unless you’ve overdone the fertiliser! Of course, it’s possible that some built up salts are trapped in the coco, so in that case, I’d suggest that you flush with an enzyme product to help break down anything stuck in the coco. I don’t think there’d be any harm in doing it every two weeks to see if the issue clears up. Your runoff pH looks good, and to be honest, so does the EC, so a lockout for those reasons seems unlikely. I’m more and more convinced it’s related to overwatering and the resulting issues, whether they be fungal, or simply dying roots affecting nutrient uptake. Anyway, thanks again for keeping us updated, I hope I’ve addressed al the various points here and that I’ve been of some use in your learning process, after all this I think you’ll be the expert in coco cultivation! All this has definitely reinforced my own preference for the simplicity of growing in living soil, that’s for certain! ‘Til next time, all the best and happy growing!

Crip 2019-12-07
Hey im still looking what problems my plants have ? How do I know if it’s a nutrient lockout? Is a lockout because of wrong ph or is it because of salt building up in the medium? My ph in the runoff water is in the 5.5-6.2 range, the ec in the runoff water is also not really high. I feed at 1.4ec atm and the runoff is around 1.5-1.6ec. If it’s a lockout, could it be that the coco starts to hold lets say potassium and my runoff ec is not too high but that ec could be mostly potassium salts? Because a ec only can read the electricity of the solution but does not read what exactly the runoff ec is made of, so maybe i have some salts that build up in the coco and causing a lockout even if the runoff isn’t too high. Or should that not be the problem i have and an lockout is caused by an high ec in the coco/runoff? Advanced Nutrients say to feed 4ml/l bloom and 2ml p/k booster, that is an ec around 2.5 ?? i only use 2ml bloom and 1ml pk so im around 1.4ec and thought about to use more fertilizer if it’s a deficiency or first flush the coco to see if its an lockout. How often do you flush in coco coir? Only if the runoff ec is getting to around 2.5? Or do you flush the coco every week or two even if the runoff ec isn’t getting too high? I think its a lockout or it could be some fungi causing this symptoms but im not really sure ? the plants also stopped stretching now and are 80cm in height, roots looking good but the leafs still die and only the big fan leafs die the smaller one at the bottom don’t loose their color. So i think if it would be a light leak at the bottom every leafs would die and my plants only the bigger leafs die ? Can only be a fungal infection/pest or a nute lockout. Greetz ✌️✌️

Crip 2019-11-30
Hey i forgot to say that the advanced nutrients doesn’t have a expiration date and their support said it doesn’t go bad if stored properly. I did another test yesterday and checked today the nutrient solution. Today it does not smell funky, i added the air stone but i turned the power from the pump really high so the water starts to wave because of the high airflow through the water and today it has not that smell so i think i will buy some better air pumps to keep the nutrient solution as oxygenated as possible. I also did take a look in the nutrients bottles if something is falling out but everything looks dissolved and no bottles have a bad smell. What i found is the coco coir is more soggy at the bottom as at the top. I didn’t add clay pebbles in the bottom for better drainage, maybe they got some standing water in the coco at the bottom and this could lead to the leaf problems ? on canna cocos grow bags it says to add something in the bottom for better drainage, just saw it on my old bags i used last grow, this time i used biobizz coco but they both feel the same in particle size so i would say that the fune coco particles have buildup in the bottom of the pots and that causes maybe root rot issues but im not yet sure about that. And i need to buy some flooding tub/reservoirs so the runoff can drain freely without water getting on the floor and leading to standing water that could cause root rot. I always took the plants/pots in a bucket and there they stand on another pot so they can drain without problems but i sometimes noticed that a small amount of runoff is getting in the griwbox floor and that this is not good i read because that water can become a breeding ground for pythium and if that water is connected to the pots standing in the little water puddle they could get some bad bacteria/fungi into the pots that causes those symptoms i have ?? And the best would be to to buy a drainage table and the runoff can flow into a bucket and the root or the pots wouldn’t be connected to the water at the floor. I was draining the pots really long like 20 minutes for each plant/pot in the buckets and took them back into the grow box so i thought im sure there will be no standing water in the box but the coco always drains some little water out of the pots even after 20minutes ? so the only thing is a drainage table to be sure all the rest runoff runs into a bucket and does not sit on the floor. They cost around 70€ for a 1.2×1.2 box but better to be sure theres no standing water near the pots. First i though maybe my osmosis water us contaminated with bad bacteria or algae or something because our house pipes are really really old 0.6ec/600ms/300ppm at 0.5 coming out of the tap water and with osmosis water im at 10ms/5ppm and i read to flush the osmosis system more often if it stands for longer time unused or if the water is hard to very hard it should get flushed more often because it helps to keep the filters clean and they would last longer and it will wash away bad bacteria that builds up inside the filters. So i will give the osmosis system a flush every three days or maybe i will flush it every day before i need some fresh water so i can be sure there are no bacteria getting buildup inside the system. (1)Do you use some sort for drainage at the bottom like clay pebbles? Many say to add around 20-30% perlite to the coco to optimize the drainage and the coco has a better air filled porosity and if perlite is added it would also help to decrease the water holding capacity so the coco would have more air in it and also the coco would not hold as much water as it holds if used pure out of the bag. ? Maybe i use around 20% perlite next time and also add 5cms of clay pebbles to the bottom of the pots. I use around 7l pots atm so there would be still enough coco in the pots if i use clay pebbles and cut the coco with some perlite. (2) have you ever tried the air pots that i found in the internet? Many say they will help to keep waterlogged soils/coco away and keep the root zone oxygenated ? they lookin good but im not sure if i should try them out. I will buy everything to be sure that the root zone gets the best environment as possible ☺️ want to grow superb cannabis and don’t want to have any problems in the future so i try to do my best to bring everything in a sweet spot and it doesn’t matter how much it costs ☺️ just want to give them the best they deserve Greetz ✌️✌️

Crip 2019-11-29
Hi thanks for the reply. The bad stored nutrients could be the problem because in Germany nearly nobody uses advanced nutrients and they always in discount in the shops i buy them so uf they would cost lets say 100euro they have 30% discount and only cost 70euros. The bottles it says to store them at 20°C and my room i store them have the temperature. In summer its sometimes 25°C and i will store them the next time in a colder room if its too hit in this room. But this nutrients i have right now always stand in a dry room with around 20°C. I did some tests and the solution doesn’t smell bad if i a lid for cover. I have to do more tests. I will use a bucket and a lid and fill it with water and nutrients and add a airpump/stone to keep the solution oxygenated and i will cut a small hole in it so the old air gets out of the bucket and hopefully no dirt particles/dust gets into the solution, i also add a waterheater ti keep the solution around 18-20°C. The dropping leaves you said because of the plants doesn’t get much light down there could be also the problem. My plants are 70cm in height right now(just measured the height) and my 600watt lamps hang around 50-60cm over the top of the plants so it could be what you said with the lights doesn’t get to the bottom and the leaves fall off. From the top the plants looking really good for my taste. I also used less fertilizer now but it doesn’t stop with the lowest leaves and i did test the runoff ec again, i feed around 1.1ec and the runoff now dropped to 0.9-1.0ec so i think they are eating more fertilizer than water if im correct what im saying. I read that if the ec is lower in the runoff the plants eating more fertilizer than water and if this happens i should increase my nutrient strength. My other plants also show the problem right now and they didn’t had it before, but the tops if the plants fill 1.2×1.2m completely out and maybe its like you said the lights doesn’t get to the bottom ☺️ damn i would love to show you some pictures to get some tips what it could be ☺️ I don’t use calmag because advanced nutrients said it will interact with the ph perfect fertilizer and it will cause ph fluctuations so i do not use calmag and i also used an unbuffered coco mix and i did not have had a problem with my seedlings because many say if the coco isn’t buffered its causing calmag problems but i didn’t had a cal or mag deficiency. This problem looks more like a potassium deficiency because of the brown edges and the leaves turning yellow and fall off after some time. I will wait some more days to see if it stops and i don’t want to change the ec every few days because it could stress the plants i think. Do you know if thats right if the runoff ec is getting lower as what i fertilize the plants? Like i said i feed 1.1ec and the runoff is now 0.9-1.0 and that indicates that the plants eat more fertilizer than water and i should increase the feedings? I think i will upload a some pictures today and post it in here so you could take a look if you want ☺️ and i hope that the fertilizers are not gone bad because the grow shops stored them for a long time because nobody use them in Germany ?? and i will take some different fertilizers next time like canna or do you know a good fertilizer for growing in coco coir? I did use the advanced nutrients because of the ph perfect but i know how to use a ph meter and only used the AN to know if i have problems its not the ph. And the ph from AN stays at 5.5-5.8 all the time i use them now so the ph should not cause this symptoms i think and the runoff ec/ph is also in the same spot. Thanks again for the reply and have a nice weekend all of you ✌️i think i will buy some seeds n stuff from your website next time i need something because you always help me out with my problems ☺️✌️✌️

Crip 2019-11-27
Hi i did some more testings now. I noticed that only the plants with the higher ec getting the problems. It looks like a potassium deficiency and maybe the calcium is in excess blocking the potassium uptake. I use the “Cannabis Nutrient Deficiency & Excess” charts from “Jorge Cervantes” and there it says excess calcium blocks potassium and because only the plants that were fed with an higher ec showing this symptoms i think it could be my problem. I was feeding the half of my plants with an ec around 1.0 to see what ec would be the best and the others git an ec around 1.5 and this plants lost the lowest leaves faster after i upped the ec. I will wait another 4days to see if they stop now with the dying leaves and will report again. Hope i get it fixed and its only the higher ec causing the problems at the moment. If it stops i will not go higher as 1.0ec in veg stage and in flowering stage with the base fertilizer and will add some pk boosters in flower and find out what they can take up and when its too much so i can start another grow with the same plants and get the best out of them next time ☺️ The ec readings are near the ec i put into the pots so i don’t think its a nutrient lockout and the ph stays also in the same range what i put into the pots. Should take a ph reading like canna says with the distilled water and some coco from the roots that would get me a better understanding of the ec and ph that is in the coco I think. How do you take readings of the coco coir? Do you check only the runoff water ph/ec or do you use the extraction method like canna says on there homepage? Greetz Crip ✌️✌️

Tim Alchimia 2019-11-29
Hey Crip, big thanks for the updates, and sorry for not replying sooner. I’ve been talking to my colleagues here at work and this issue of yours has got us scratching our heads! With regards to the funny smelling nutrient solution, could it be that the nutrients are out of date, or stored badly? I’m sure you stored them correctly once you bought them, but you never know how they were treated beforehand. Adding bacteria or organic products o the nutrient solution can definitely make things start to stink after a few days, so maybe it’s simply a case of changing the solution more frequently. And good work spotting the fertiliser residue inside the watering can, I think that will definitely make things easier to control from now on. I can’t remember if I asked you whether you were using CalMag or not, I know it’s supposed to be essential when using RO water, but I’m not sure if the AN fertiliser schedule allows for this or not. Again, I’m sure you’ve got that under control but no harm in checking, especially as you suspect some possible Calcium excess here. Another thing to consider is that the lower leaves dropping might be simply because they aren’t getting enough light, hence they drop naturally. I know this is something I frequently experience with my mother plants. The coco growers I know generally only check the runoff, although in the case of any problems I think using the extraction method would give much more reliable results. I’d have a go at that if I was you. I’ve got a feeling that the issue will turn out to be a simple case of over-fertilisation. At least that’s what I’m hoping, anyway! Keep us posted, have a great weekend and most of all, have fun growing! All the best.

Crip 2019-11-24
Hey i am in day 2 of flowering now. I did use less fertilizer the last time around 1.1ec for some plants that were smaller and 1.3ec for plants that were some bigger. I first thought it stopped but today the leaves at the bottom die again. The runoff ec is mostly 0.1-0.2ec higher than the ec i put into the pots. So 1.1ec feed, drain 1.2-1.3ec. The leaves don’t look like Nitrogen overfeed. They dont claw and they are not dark ? The leaves at the bottom start to go brown at the edges and the tips of the leaves. And the whole leaf look like they get lighter in color but the edges turn brown and get dry. Hard to tell how they look like. Maybe you know what the problem is, i will upload a picture on a website where i can upload pictures there and if you want you could take a look at it. I also did a test and the osmosis water doesn’t smell or look like it had some bacteria in it but if i mix it with my nutrients it starts to smell like rotten eggs after one to two days. If i mix beneficial bacteria to the solution the water smells like old water and has a rotten smell after some time. With beneficial it doesn’t smell like Sulphur ‘rotten egg smell’ but it has some weird smell that i smell like something starts to rot. Don’t know if there are bad bacteria in my osmosis water or if something like mold spores fly into the nutrient solution and start to grow inside the solution ? I do more test tonight and i will cover the solution so no particles can fly into it. I used only my airpump/airstone and placed it into my watering can after i cleaned it. Your website needs a forum where people can upload pictures and where you could help them that would be great ☺️? i would be online 24/7 because i have always some questions ? I think an ec at 1.1-1.3 isn’t too high. My plants are 50cms in hight and i had to take them into flowering or they will grow too much and i get problems with the lamp to plant distance. I also have the lamps not too close and not too far away, i found some instructions from adjust a wing reflectors how far the lights should be away in each stage of the plants life. I will write back tomorrow or in around two days. ✌️✌️✌️

Crip 2019-11-18
Hey so after i had transplanted into 7L i watered the half with 2ml/1.2ec and the other half with 3ml/1.5-1.7ec. After three days every plant stopped with the dying leaves but i waited one more day if something change but every plant looked fine/fast growing/no dead leaves. So i watered all with 3ml/1.5-1.7ec again, i didn’t see that the plants with the lower ec were slower or so and the others with the higher ec looked the same. 2days ago i was looking for the roots coming out of the drainage holes, they have a huge root mass coming out of the holes. And what i noticed the leaves started to die again ?? and the leaves getting darker like last time. The days after the transplant the leaves stopped dying and the color turned to a normal green, not to dark not to light. Before the transplant the leaves started to turn too dark so i think it has to do with the water frequency. Like last transplant the plants started to dry out very quickly and now this also happens, two days ago they were not completely dry but the pots were light in weight like the last time before the transplant. Its not the nutrient strength i think because they would not have turned a normal green after the transplant and they had the same nutrient strength. I think it has to do with the watering frequency. If it’s getting too dry the unused salts like Nitrogen will accumulate and i noticed the ec in the runoff rises. Feeding with 1.6ec runoff is 2.0ec, i took the runoff reading yesterday and today i was feeling two times per day so they don’t get too dry in the morning like the last times and to find out if it helps to stop the dying leaves and to bring the ec a little bit down. If in three to four days it does not work i will flush the coco and go back to 2ml/1.2ec and see if this helps. I think if the runoff ec is getting too high in the growth stage the plants will show problems and to bring the runoff back to normal it would be the best to increase the waterings to flush out the leftover salts and they don’t dry out too fast what also leads to salt accumulation. If they had problems with Nitrogen they would have showed the problems last time after i transplanted and the leaves would be dark and dead if i didn’t used a lower ec but they didn’t had problems after the transplant and only show symptoms of Nitrogen toxicity after they start to dry out more quickly. So i will see if this helps and the plants stop with this problems and maybe im feeding near the N toxic limit and after they dry out more salts accumulate and then they show the symptoms again so i think if they don’t get to dry and the salts dont accumulate they will be fine. I also could use less nutrients and only feed one time a day and would need a flush after some days if the ec is getting to 2.0 in the runoff. Would be easier with lower feeding i think but I want to know if im at the limit with the Nitrogen and if it helps increasing the waterings. If it helps i know how much the plants tolerate and can make a notice for the next grow and then i think i would feed between the 1.2-1.6 ec and would not have any problems and only look at the runoff ec that doesn’t get over 1.8ec and would be fine and can water only one time a day and have no stress at all. One thing i found is that the watering can i use to feed/mix my nutrients has some leftover on the walls, the two parts nutrients from AN has some organic and saltsi n the part A and the part B contains only salts, the part A smells like molasses and is Brown in color the part B doesn’t smell and has no color. The nutrient containers show the brown stuff in part a at the opening(where i take out the nutrients with my syringe) and the part b has some salts there and the brown stuff on the watering can must be the part a stuff that dried out over the last weeks after i watered the plants and let the can stand overnight night and filled it with water again. So this leftover in the can could also lead to problems if some of this stuff getting into the new water and i make the new solution some of it could be solved again and that would lead to too much Nitrogen. The part A only contains different Nitrogen salts and Calcium and some micro nutrients if im right. But if this accumulation in the can was also after i transplanted it would have shown the Nitrogen problem from the start after the transplant. Or this accumulated salts in the can did accumulated in the coco after some time like last time before the transplant and showed the problems only after some weeks because it did accumulate slowly in the coco and after the transplant the fresh coco didn’t show the problems because in the new coco no accumulated salts were in there and now after nearly two weeks it also started to accumulate in the coco and is now showing the same symptoms. I think it could be it because this leftover in the can would lead to a unbalanced nutrient solution and the plants showing toxicity signs because the solution has too much Nitrogen that dissolved all the time i made a new mixture. I cleaned the watering cans today and the water turned really brown like if i would mix the part a in the water ? i was cleaning every thing near the grow tent and in the grow tent but didn’t take a look into the watering cans ? I will get bucket or something like this to mix the nutrients so i can clean it regularly and be safe there’s no leftover that could lead to a unbalanced solution. I use darkblue cans and you don’t see this leftover if you don’t take a look where its sunny or enough light to see whats inside there ? and my hands don’t fit easily in the can openings so i will use some nutrient tank in the next days ? Would be so stupid if that was the problem but its always good to have a clean tank/can so the solution don’t accumulate salts from the last mixture and the new solutions don’t get to a toxic level of some minerals. I topped my plants two days ago and will try some LST to bring all the shoots/branches in the same height and they hopefully fill out the complete grow area. I had always too many plants in the box and the humidity was getting out of control in the flowing stage so i always had to cut some lower leaves and branches away but that only helped a little bit and with less plants that have the same heights and enough branches i will get the same harvests and there are not soo much branches/leaves like 20plants that had no low stress training and were 1.5 meters in height ? i never did that before with the topping and lst and i just let the plants grow like in nature but it always was a tent full of huge plants and millions of leaves/buds touching each other and bringing my humidity in the danger zone. I hope with less plants/topping/lst i can bring the humidity more down and the buds don’t start to touch each other if im lst in the first two weeks of flower and bring the shoots in the same height and cut out the lower branches/leaves that only turn into popcorn buds. I will write back in some days what the problem was or if im still have the problems. The accumulated salts in the watering can or the accumulated salts in the coco because of drying out too fast should be the problem i think. The watering can gets a clean up every five days or if they have leftover again tomorrow i will use something different to mix the solution or clean it every day until i got a good nutrient tank and can wash the leftover away more easily. ✌️✌️✌️

Crip 2019-11-08
Hi thanks for the feedback 🙂 i use osmosis water 0.09ec. Ok i think i will buy a humidifier and for my next grow i will have the perfect environment and maybe i buy a PAR meter so i can test how close i can get with the MH and HPS lamps. Today they got some slight leaves clawing and the leaves look a little darker. I have friend and he also uses really low ec for his plants but he grows in a selfmade recirculating system and uses advanced hydroponics 3part fertilizer and if i remember right this fertilizer is stronger and mixing the right grow/micro/bloom for every stage is difficult because he has strains that grow perfectly if he goes by the feeding chart(only use less what the charts say but mixing the fertilizer in the same ratio as the charts says) and other strains(sativa) are not doing good he said and i think he must find the right ratio and maybe use less grow fertilizer because some sativa don’t like too much Nitrogen. And that is something i will try if i have my coco grows dialed in and get the best out of it (that could be in a year or two if im doing everything right) and then i will try a hydroponic system because i think if something goes wrong they will die quickly if you don’t know what to do or act to slow or do something wrong and in coco you can learn the basics like how much to feed different strains, getting everything dialed in and learn how deficiency and excess look like, if i know this basics its much easier to find out what is wrong with your plants in a hydroponic system I did test how hot the 600w lamp is and i could go down to 15cm i think, if i put my hands backside under the lamp near or at the top of the plants my hand doesn’t get warm. i use a Adjust-a-Wing reflector and this reflector doesn’t have Hotspots like the normal reflectors and the small ventilator hangs right behind the reflector near the lamp to bring some more heat away from the bulb but i think a PAR meter would be the best option to find the right light intensity for all the stages of growth. I also read an article if the plants are under/overwatered that can stress the plants and my plants were in the 2L pots and the last three days they always were really dry on the next day so they maybe dried out over night a little bit too fast and if the coco gets too dry this can damage the fine root hairs and also the root tips can die back if its too dry and the plants needed some water and this maybe caused stress to the plants. Today i also saw the fanleaves were a little bit droopy and the pots were very light, i did a transplant into 7L pots today and i will feed half of them with the 1.6ec and the other plants i use the 2ml/1.0-1.2ec and will wait a week to see if they stop with this Toxicity symptoms. If all plants stop showing signs of the toxicity than it maybe was the too dry coco the last few days and if the plants that i feed higher still show symptoms it must be too much N from the high ec and i will feed them like the others. Last grow i also waited until the 2l pots were completely full with roots and last time they also dried out quickly but i transplanted them after i saw they dry out too fast and i continued with the 3ml and upped to 4ml. I wrote with some growers and the most of them use the AN fertilizer at full strength but they use LED lights so they don’t drink as much as a plant under a HPS lamp and they don’t take up too much N in a short time, like the article from canna coco that LED lights produce less heat and you can use more fertilizer without burning the plants but if its a HPS lamp they would take up way more Nitrogen that leads to overfeeding symptoms and if this article is right. If i find the article i will give you the link here in the comments. Maybe i will buy sometime a LED light than i would use the led and the hps in the same box and a wall between to find out if i can feed them higher under led without burning them. I never thought about getting leds because i alway used hps lamps and i think the hps lamps will give you more yields and leds are good for summer times so the box wouldn’t heat up like a hps lamp in summer and the plants would do better as a plant under hps in hot summers month. Growing is amazing because you can do so many tests/different things and you will always learn something different and you can buy soo much different things for growing ☺️ im happy, my garden is so big and i always plant vegetables every year/salad/tomatoes/strawberrys/raspberrys and more ? i have two apples trees that are older than me and they taste so good and it doesn’t cost any money ? that garden is so big but in every corner grows something different in summer. You need no hobbys if you have so much garden work to do ☺️ Sometime i think i read too much about growing/plant problems and if you find articles that soo many things like heat stress/over/underwatering can give you problems that could lead to weird plant problems this can give you a real headache ?. If all this informations are correct i will learn and maybe know the next time what maybe can cause different problems and i can sort it out or do some tests, if the environment is dialed in that would be great and i could be sure if i have problems that the environment is not causing problems and the problems i fix in different grows will not appear so easily if i know what went wrong and can avoid it before it happens again. I only have to watch out how much fertilizer i should use and see if the plants show toxicity symptoms so i can act quickly and use less fertilizer/notice it if i grow that strain again so i would always have some informations about each strain i did grow before. And i have to watch out if the plants in the coco start to dry out too quickly and react faster as this time and the last grow so they don’t getting stressed if i transplant at the right time. The roots looked white today i did the transplant. After i did the transplant and watered the plants the leaves that looked a little bit droopy are not droopy anymore i did take a look an hour ago so they really needed the transplant and some more water so are not dry again tomorrow. If i find the problem fast enough i think i will use the 7l pots for the flowering stage and i have to handwater maybe 2to3 times per day in the stage where the buds start to swell, i will see how fast it dries out and if i need some more weeks to figure my problem out i could transplant into a 10-14L pot if the 7l pots dry out too fast. I also think about getting a automatic watering system because i use now a 40L tank where i can mix some nutrients so i don’t need to mix every time i need to water them like i did last grow and added a Airstone so the solution stays fresh and i don’t need hours to mix and water all the plants. ☺️ I think it will get better every grow i finish because i learn from my errors and get useful tips from you ☺️ and if i find out the problems with different tests i can bring everything into perfect condition plus a perfect environment. Next seeds i start i will use the ugro coco again but i will flush a small amount for the seedlings so they have clean coco and add the beneficial bacteria/fungi to the nutrient solution like i did this time so the beneficials take hold in the flushed coco (The Piranha and Tarantula from Advanced Nutrients contain many bacteria and Fungi but the stuff costs little too much but the ph perfect fertilizer are a great thing so you don’t have to worry about ph lockouts and maybe in some years more companys bring those ph perfect fertilizers) And if they grow in the flushed ugro coco im sure that the seedlings two month ago had some sort of shock or the salts maybe caused root damage and that maybe were to much for a seedling/young plant, i think if they have some root mass they could handle the 0.4-0.6ec salts out of the coco or the problem could be something totally different but i will see it with the next seeds ☺️ And thank you for reading my long storys all the time/give me tips and information ☺️ and i will write if i see that the plants stopped with the crispy leaves/nitrogen toxi city ✌️✌️✌️

Tim Alchimia 2019-11-11
Hey crip, thanks for getting back to us. Glad to hear you’re using RO water, good stuff! I totally agree with everything you say here, you are going to have learned so much through this process and you’ll come out the other side with a great deal of experience and as a great grower, I’m convinced of it! Your analytical approach and your willingness to experiment and to see the results for your self are very valuable assets, and they will serve you well. You’re correct about the amount of information available online and the confusion and uncertainty that can stem from reading too many articles about plants. it’s easy to get overloaded with information, but with time you’ll easily be able to distinguish real information from all the internet click-bait that’s out there. As you say, there are a lot of things out there that we can buy for our hobby, but not everything is essential. Having said that, I think your idea to get a LED lamp is a great one because if you end up liking the results you get from it you’ll be able to put the HPS away and grow in a more sustainable and energy-efficient way, and cheaper to run too! The technology has improved greatly over the last few years, and the yields too. An automatic irrigation system can be a great time and labour saver too if it’s set up correctly, although I get the impression that you will do a great job dialling that in too. I can’t wait to hear how this round finishes and how you get on with the next round. Thanks again for sharing your experiences with us, it’s great to be learning together! All the best and happy growing!

Crip 2019-11-08
Hi it’s me again, sorry if i didn’t write back how it went out last grow but now i will write what did happen to the seedling that didn’t grow and how i fixed it with some more seeds that i tested and i have a problem and not sure if it s the nutes or something totally different. sorry for the long text now and i hope some one can help me here with my new problems. If the text is too long you can jump down to (A) for short text,1. And 2. There are my questions. But would be great if someone reads everything its really detailed and no one on another grow forum had an idea and Advanced Nutrients also didn’t helped me that much and only i should follow what the charts say. (A)In short; my plants show the same symptoms as my plants in the last grow, didn’t found what the prob was, the symptoms begin 3weeks after the seedlings showed their heads, i followed the nute charts and i think its Nitrogen toxicity or low humidity causing the plants to uptake more water and nutrients because of the higher evaporation, high ec targets causing the problems for) in growth stage because advanced nutrients says to follow the charts but at week3 i should use 3ml and that is an ec of 1.5, week four 4ml ec 2.0 the problems, lower leaves get crispy dry out after a week and continues/ec targets from the run off are around 0.3ec higher if i feed at 1.5ec but climb over 2.5ec if i use 2.0feed like AN told me last time and i should get no nute burn, leaves don’t show the typical N toxic symptoms like clawing/dark leaves but have weak stems/lower yields excess foliage in flower and less smell and taste? would be great if someone has time to read everything and can give me some tips if im right with nitrogen toxicity or too much fertilizer or the lower humidity causing higher uptake of water nutes and that burns my plants or let the lowest leaves start to die and if the tests i would make with my plants, to find out what is causing it, is a good idea or if you know that maybe the ec readings are too high because 2.0ec in the grow stage seems a little bit high to me. The problems i had with the seedlings in coco that i wrote two months ago, didn’t stop and i used some different coco (biobizz) and flushed the coco until the runoff was at 0.1ec, let the coco dry down some days and put the seedlings that germinated in peat moss plugs in the coco and gave them the 1ml like advanced nutrients said and i watered around 50-100ml and waited till the coco dried up but not completely dry and i used only a 250ml pot filled with coco so i can be sure that the coco dries down in 3days. The plants looked really nice this time with healthy white roots and they got transplanted after 8days in 2L pots, the 250ml pots were full of roots, i would say they were rootbound but it didn’t gave any problems and the roots also started to explode in the 2l pots and after 12days they did drink the 2l pots(holds around 500-800ml of water/nutrients) empty in one day ☺️ was really happy with the fast growth and the healthy roots. Thanks for all the tips and help that you gave me, that really helped me how i should water seedlings in coco and what maybe caused the problems with my seedlings that didn’t grow and didn’t got a good root mass. That tips and your article helped me alot and like now with my new problems i maybe think what the new problems are because your article about plant nutrient deficiency/excess is really good? I did finish the grow one week ago, i used 7l pots after the the 2l pots were full of roots and the plants started to drink so much water nutrients, but i had some problems in the growth stages around week 3 and i could not figure out what went wrong. I harvested around 0.5 gram per watt(could be more but i think if i find the problem that caused some leave problems, i will get a better harvest this grow or the next one). I checked the drain ec and the ec went over 2.5 after i started feeding the full strength 2.0ec but at 1.5ec it never went over 1.8ec in the runoff, i think its good to measure the runoff so you see when it’s time to flush but i should have stopped giving them 2.0ec in growth stage and the 1.5ec also was maybe to much because of the dying lower leaves, and i should have used only 1.0ec to find out if the high ec or some nutrient that is in excess gave me the problems. I have at the moment 7 plants that are 3 weeks into the growth stage and this plants also show the same symptoms as the last one. I follow the nutrient chart from advanced nutrients and i think that they maybe get the problems because of too much fertilizer or something isn’t right with my environment that leads to stress and that causes the nutrient problem. 1ml of the grow fertilizer is around 0.5ec and AN says to up the feeding every week by 1ml until week four with 4ml of their grow fertilizer. Im in week three and use the 3ml as the bottle/feeding chart says and last time that also caused the problems. 3ml are 1.5ec and next week would be 4ml and the ec would be 2.0. I think that this ec targets are way too much for a plants that is three weeks into the growth stage and the 2.0ec seems very high because i read that cannabis uses around 1.2ec in the growing phase and up to 2.0ec(depending on the strain/environment/NPK) in the flowering stage and drops down in the last week’s of flower. Back to my problems, so i feed them with an ec of 1.5 and the plants get some crispy leaves at the bottom, the tips of all leaves don’t show tip burn but i could be wrong because the crispy lower leaves start at the tips and getting crumbly/dry. The lower leaves start to dry out after 5days and it climbs to the middle leaves and i didn’t used less fertilizer last time but the problem got under control some weeks into flower and maybe the bloom fertilizer has not that much nitrogen or time realising nitrogen as the grow fertilizer and the plants took up all the excess that build up in the plant tissue over the time in the growth stages and that maybe stopped it. I think it is too much Nitrogen but the plants don’t show very dark green leaves and don’t show clawing leaves, but i read your article about Nitrogen deficiency and toxicity and the symptoms like excessive foliage (in flower stage), weak stems, taste and smell of the harvested buds are less because my plants in soil taste and smell way better even if my soil plants have a hard time during hot weather that was what i noticed in my last grow, the picture from your article with the plant that shows Nitrogen toxicity and the clawing leaves look similar to mine, my plants don’t show that clawing and i read that not every plant shows that symptoms. My plants look some darker as the Nitrogen toxicity picture from the plants in your article but they also don’t look like that really dark green or leathery leaves like i found on some other websites or pictures on Google and the top of the plants still grow very fast only the lower leaves making problems. The lowest leaves get enough light im sure because the plants don’t have too much internode space and the 600w hps produce more than enough light. ? But i still think it has to do with Nitrogen, last grow i though something is wrong with the roots, they started to look unhealthy two weeks later after i noticed the leaves dying or getting crispy/dry and fall off. I checked with a magnifying glass if i have root aphids or some root pests but could not find any aphid or other insects in the coco/roots, i also checked the whole plant if they have insects eating on that unhealthy leaves but didn’t find anything and the coco/roots didn’t had a bad smell. So i started to use good bacteria and fungi that i add to the water this grow at the moment and the roots looking better as last time and because i flushed the coco before i put the seedlings in i added the supplements and i can definitely see difference in the health of the roots this time. But the last grow the plants also had healthy roots until the problem began and now the same thing happens again and i use the root supplements and the fungi/bacteria supplements so i don’t think it was root rot or bad bacterial gr owth in the coco last time because this beneficial bacteria and the root supplement should bring bad bacteria under control and it’s also not overwatering. I started with 250ml pots and watered about 50-100ml every three days after the coco started dry out and i upped the water volume after they started to drink more, i waited til the small pots were completely full with roots and transplant in 2l pots, watered around 100-150ml and upped the amount if needed. The Advanced nutrients support said to me i should follow the instructions, i showed them pictures of my plants and the affected leaves but they also couldn’t figure out what is causing this problems. I wrote them every detail like temperature/humidity/feeding/light distance/watering cycles/exhaust ventilation and normal ventilation and how the ventilators are placed.. My temperature is always around 20-24°C and in the winter time the dark cycle the temperature falls down to 15°C so i heat up the room a little bit to get around 18°C in the night time. The light is around 45-60 cm away and i bring the light closer to the plants after some days or if i see heat stress/light stress i put the light some away, i only have heat stress in the summer times if its very hot outside and i know how this looks like/taco leaves/leave edges turn up. I also know how light stress looks like because the buds getting discolored or white if they are really close to the lights or the leaves get a light color or start to burn, The exhaust ventilator has 600-1100cbm/h and runs at 600 if i only use one 600watt lamp and full speed in the summer if its hot and more watts are running. The other ventilators bring the air to circulate in the box and one is near the lamps to bring the heat away and the other ventilator is at the bottom so that the air circulate and no ventilator is pointed on the plants/leaves to avoid wind burn that i had in my very first grows. I water the 3 week old plants with around 1000-1500ml and wait for around three days until the pot feel light but don’t get totally dry and i water more if they drink more or i transplant if they really need much water/in flower if they start to drink like crazy i need to feed two times per day depending on what pot size i choose for their final pots. In 7l pots they need two times per day feeding if they drink more the first few weeks where they develop buds. Or i use 10L pots and only need one watering if they drink more, and also stop watering that much in the last weeks of flower when they stop driniking that much like they do in the bud development stage and i always check how heavy/light the pots are so im sure i dont water too often or too much. And the last thing is the humidity that is not ideal but i read if it dont drop below 40% the plants should not have problems in the grow stage, if the plants start to fill out the box the humidity automatically is around 50-60. But in the first few weeks of grow the humidity is around 40-50% depending if i have to use a room heater. I maybe get an humidifier next time to find out if that helps. I mostly spray the leaves of the plants and the walls of the box with a sprayer so i bring the humidity up and the leaves don’t get too dry, i only do that for one week after the seedling pops out of the coco and i also did it without the sprayer and i didn’t notice any difference in the first two weeks of the growth stage. Sorry for all that information and that never ending text but i want to detail everything as best as i can. Back to the problem in week three of grow. I thought about the humidity maybe causing this problem because the first two weeks the plants has not soo much leaves and doesn’t evaporate as much water as a plant that has double the leave mass. And if the plants don’t evaporate as much water because they don’t have a big enough leave mass they also don’t drink that much water and also nutrients would not be absorbed as fast as a plant that evaporate more water because of more leave mass. And maybe at week three they have enough foliage and they start to evaporate now more water because the humidity is low and i read somewhere on a grower website that a plant that has a dry environment will use more water and also suck in more nutrients and that the humidity if too low can cause plant stress and this stress can also affect the nutrient uptake and if you feed too much or one nutrient is in excess it will show way faster nutrient problems/burn as a plant that has perfect condition and has no stress and that plant would use way more nutrients as in a climate that has higher humidity. And i think that could be right with the uptake of nutrients and if they now use up more nitrogen or use too much in a short time because the plants evaporate more and that leads to more water/nute uptake and maybe they didn’t use that much a week ago and didn’t evaporate as much water and so they didn’t drink as much water and nutrients that this excess water uptake causes Nitrogen toxicity and the low humidity maybe stress the plants now even more and the symptoms getting worse if the humidity doesn’t get in the ideal area like 50-60% in growth stage. Sorry i mean if the plants got more foliage and the humidity is low then they will automatically take up more water/nutes as a week before because they had not that much foliage and if they need to evaporate more and keep the leaves cool and that the leaves doesn’t dry out they will also use more water and nutrients and because they suck in more nutrients as a plant would need in a better environment with higher humidity the plant would use less water and nutes so they wouldn’t uptake excessive fertilizer like the plant that is in an low humidity area, but if that plant is needs now more water but uses too much fertilizer the easiest way would be to lower the nutrients until the plants fill the box and the humidity stabilizes and than up the feeding, or getting an humidifier for perfect condition so i could feed what the bottle says and maybe they would not get that leave burn or dying leaves. I also read if the humidity is too low the plants getting problems with the evaporation that could make the leaves heavier because they cant evaporate any water, the stomata doesn’t work correct if its too low or something like that controls the evaporation/cooling process of the leaves.. Maybe i should sometimes spray the leaves with osmosis water but im not sure if all this is causing my problems.. Hope you can give me some tips if that is right with the low humidity/higher evaporation and higher nutrient uptake leadingto toxicity/excessive nutrient uptake (because the plants need to cool the leaves with water that evaporate quickly in low humidity) in the third week of the growing stage and the first two weeks they didn’t show symptoms because they had not enough leave mass so there the symptoms didn’t show. And if its so dramatic if the humidity is around 40-50% in the growing stage because that is the only point in my grow tent that is not in the ideal range and i will maybe change it if its really causing that problems. So that are my two questions. 1. I am just feeding to much in the growth stage and should i aim for an ec around 1.0-1.2 and don’t listen to AN because they say i can follow the charts and don’t get nute burn even if i feed 1.5-2.0ec at week three and four? I think a plant can handle that high ec if they get sunlight or more than 1000w per 1.2×1.2m and have ideal conditions like measuring the light intensity with a digital meter so the plants get exactly the right lumens for every stage and i only can hang the lights down what the manufacturer of that lights says like maximum 40cm and minimum 60cm but you will never know if its ideal and like the humidity if its too low. The temperature in the summer times also get too hot if it has 30°C outside and you grow under the roof with a box that gets heated from the roof, the 600w hps lamps the growbox temperature will not go under 26°C and only a cooling system would help. That and a humidifier and maybe a controlled exhaust ventilation that controls humidity and temperature costs a lot of money and the el ectricity costs would go up like crazy if all that stuff need electricity. 2. Could the not ideal humidity caused the problems like i said that only starts to show in the third week because of the higher nute/water uptake because of the higher evaporation? And i really could believe that with the low humidity forcing the plants to uptake more water and also the nutrients and after some time they store excess of N or P or K and that will show after some time in dying leaves. If thats it i will test it with some more seeds and give them perfect humidity from day one and see if they doesn’t get this problem if they grt into week three, if they get the problem they just get too much fertilizer. I also read on Canna Cocos Website that a plant needs more nutrients under a LED because the LED doesn’t produce so much heat and the plants don’t need to evaporate that much water and so they have a harder time to uptake nutes if fed to low and they also said this with a hps lamp that produces much more heat that it better to use lower nutes because they can burn more easily because they use up more nutes. And if canna say use less i think that the humidity maybe doesn’t matter but the heat from the hps lamp and so they suck up too much nutes. I think i will do another test. I have 8 plants and they have the same conditions, i will use 4plants and back up the feeding to 2ml around 1.0-1.1 ec and wait around a week if the dying leaves stop and the plants show recovery or lookin healthier with that strength. The other 4 i will continue with the 3ml 1.5ec and up to 4ml 2.0 ec in week four so i will definitely see if the one i fed lower recover or if it doesn’t matter and they still have this problems after one/two weeks. If it doesn’t stop i will continue with 4 plants only 1.0ec and the other 4 as the nutrient chart says and than i will buy a humidifier to bring up the humidity and divide my growbox in two with a wall in the middle and the plants that get the 2.0ec will get the humidifier and the others that getting a lower feed don’t get humidity and wait again 1/2 weeks to see if the humidity is causing it. If the plants that getting the higher feed and humidity stop getting worse or recover i will take away the wall so the plants that still have the problem with the lower feed also get the right humidity. If the plants with the high ec doesn’t show signs of improvement/dying leaves don’t stop i will set the humidifier to the other plants and don’t take the wall away so i could really find out if the high feed and higher humidity stops that problem and they take up the nutrients without dying leaves. if lower feeding would help, if the low humidity is causing the plants uptake too much nutrients because of the evaporation i also will find out if the humidity is ideal and i still feed only 1.2ec and they only need a lower ec no matter what humidity i use. So i find out if they uptake/tolerate more nutes with a better humidity or if the real reason is just the high ec no matter what the humidity says.

Tim Alchimia 2019-11-08
Hey Crip, good to hear from you again, thanks for giving us the full story! It sounds like you’re figuring things out over there, and I think that if you keep up the same analytical approach, you’ll definitely hit on the root cause of the problem. AFTER Discussing the issue with a colleague here at work, we both agree that an EC of 2 is far too much, and 1.5 should be the absolute maximum EC reading. It definitely sounds like the main problem is Nitrogen toxicity, possibly exacerbated by the low humidity in the early growth period. One thing I don’t think I’ve asked you before is about the water you’re using. Are you using Reverse Osmosis water, tap water, or spring water? Have you tested the EC of the plain water, before adding any nutrients? I’ve got a feeling that the AN charts are calibrated for RO water, with an EC of 0, so if you’re using another type of you’ll need to measure the EC and to compensate for any potential variation. On a side note, I know plenty of experienced growers that aways use half the stated dose on the bottle or in the schedule and they swear by this approach! As for the humidity, I think you’d be doing yourself a great favour by getting a humidifier. I think anything you can do to create the perfect growing conditions is a good idea, and humidifiers aren’t too expensive an investment, relatively speaking. That’s an interesting point you read regarding plants needing higher doses of nutrients if they’re under LED lights. I haven’t heard that before, I will have a look into it, but I would imagine that if you’re keeping a correct temperature in the grow tent, then the heat produced by the lamp itself shouldn’t have much influence. Please let us know how your experiments go, I’m looking forward to seeing how things turn out and if we can get to the bottom of this problem! All the best, happy growing mate!

Crip 2019-09-02
Thanks mate 🙂 i didnt add calmag to the Advanced nutrients fertilizer and i did feed some seedlings with 2ml and they look more green. The other seeds still have the yellow top and some brown spots between the margins. I was on the ugro Website and found a article how they buffer the coco coir and how to use it if i hydrate the brick. I will copy it in the comments: THE COMPLETE MANUFACTURING PROCESS WOULD BE: 1. Washing in fresh water, dragging a large part of the salts by dissolution 2. Chemical buffering 3. Second washing in fresh water, dragging by leaching a large part of the salts resulting from chemical buffering. The result is a substrate with an EC of 0.4 mS/cm in a measurement of 1 volume of substrate in 1.5 volumes of water. Even after this process, the decomposition of coconut organic matter releases sodium salts, so liquid fertilizers for coconut carry a calcium reinforcement in the formula so that there is always available calcium. WHAT DOES THIS BUFFERING IMPLY IN THE USE OF THE PRODUCT? To use this type of substrate it is recommended to start the fertigation with an EC level of 1 mS/cm and rectify if necessary. An excess of fertilization could lead to an excess of calcium, which would produce a chemical block of iron, the result of which would be a radical stop in the plant’s growth and severe deficiencies in a short time. If this occurs, the plant should be spray with chelated iron and the EC level should be lowered below 1 mS for one or two irrigations. After the buffering they wash it with fresh water and i think if you would buffer with calcium the coco absorbs it and release the potassium/chloride in that buffering solution. And if they wash it down to 0.4ec the salts would be a mix of the buffering solution and most would be NaCl/potassium and maybe thats too much NaCl for the seedling, but im not 100% sure and they say to start feeding the coco with an ec of 1.0 and i only used 0.6ec what the Advanced nutrients says on the bottles. I think the guys from ugro know it better how their coco works and what ec to add so you have enough calcium for the plants. But they say if the ec of 1.0 is too much calcium toxicity occurs and the plants stop growing and get a iron deficiency and decrease the next two feedings? my seedlings only have one true leave and the second is light green and still no real growth with the most seedlings. And i think i cant say if its a calcium deficiency or toxicity ? but i didnt start feeding with the 1.0ec so i think its a deficiency. The seedlings i water with 0.6ec like advanced nutrients say have the lime green heads, the other seeds i use only 0.3ec to see if they grow faster but they are the slowest and the other seedling i use 1.0ec and they dont have the lime green head but still growing slow ? I think i will give them all the 1.0ec and hope they dont get a nute burn later, the ec sounds really high for seedlings and i also asked them if i should use 1.0ec if i plant seedlings into their coco, and if i should wash out that 0.4ec salts with the nutrient solution at 1.0ec or only water the pots a little and dont care about the salts in the coco. Canna coco says with their fertilizer and their coco you must add 0.6ec of their coco fertilizer because of the buffers and normal you use tapwater with this nutrients so the ec would be also around 0.9-1.0 if you add the seedlings in their coco n and the coco nutes. I also dont feed until the coco lookin light brown on the top and i hope the seedlings just build their root structure in the coco and will give me fast growing plants in some days. Would you add an ec of 1.0 like the guide from ugro says even if you put the seedlings in the coco? ? Dont know how much salts or ec a seedling can handle and dont get burnt or grow slow because of too much fertilizer. If you write an article about how to start seeds in coco i really would love it. I read every article the next weeks and keep up the good work and thanks again that you always write back and i will comment the next days if something has improved or if the plants are still lazy ?

Crip 2019-09-01
Hey Crip again i have some more question and sorry for all the questions. Advanced nutrients coco fertilizer says to add 1ml/l for seedlings and maybe i added the fertilizer too early? I thought the seedling stage begins after the seed germinate and open the cotyledons and i didnt got an answer back from advanced nutrients. So maybe the burn came from the fertilizer. And another thing that maybe caused this burning was the flushed out coco buffer and maybe the ec 0.5 in the ugro coco is the calmag buffer. I used the 500ml pots and added about 1-150ml of nutrient solution and it drained really quickly, and the chloride gets released if you wash out the buffer and the nutrient solution goes into the coco and the calcium Magnesium gets bond to the coco because of the CEC in coco. At the website from canna coco they have an article if you flush the coco without nutrients or too low nutrients you will wash away the buffer and calmag deficiency starts. Really hard to find out what the problem is, maybe the fertilizer added too early, the buffers washed away and released the chloride. Today the plants show signs of a calcium deficiency on their first leaves, small brown points in the middle of the leaves, the head lookin yellow and a little twisted. Maybe it is the Advanced nutrients fertilizer because the coco fertilizer only contains 3.5% calcium and all other coco fertilizer has up to 5% of calcium. The fertilizer must be used with osmosis water because only with osmosis water the ph perfect works ? i tried tapwater and the ph was waay too high and advanced nutrients says you should not adjust the ph or you will get more problems.. I thought this fertilizer is simple like they say on the website.. I have some more seeds germinated yesterday and i did put them into the coco some hours ago. 2 seeds i only gave them water without nutrients about 75ml in the 500ml pots, 2 seeds i did flush the coco with nutrients until the runoff had the same ec 0.6 of the Advanced nutrients fertilizer and put the seeds into the coco. 2 seeds i added only 0.5ml/l fertilizer and also flushed the coco and put the seeds into it, and two more seeds i added fertilizer but i dint flush the coco only 75ml of nute solution. Dont know why the other seedlings show now signs of calcium deficiency but advanced nutrients says dont use calmag or it will change the ph perfect and they say the base nutrients have enough calcium in it. You should make an article about starting seeds into coco and how to feed them, how much water that would be so great. I cant find any good article. One Website says feed three times per day after the seedlings germinated and add fertilizer between 0.4-1.2 ec. Others say flush out the coco before set the seedlings in it and start to feed after one or two weeks. Never saw so many different opinions how to grow seedlings in coco coir ? or maybe im just to stupid to understand how it works..

Tim Alchimia 2019-09-02
Hey Crip, don’t worry about the questions, we’re here to help if we can! I can’t comment much about Advanced Nutrients products as we don’t sell them here at Alchimia, but I can fully sympathise with all the conflicting advice and contradictory instructions, I don’t think it’s a case of you being too stupid to understand it at all! It all reminds me why I chose to grow in organic soil and pretty much forget about EC and pH levels! In this case, I understand you’re concerned you may have washed away the buffering, but given what Advanced Nutrients claim about their products I honestly don’t know if it’s a good idea to add any calmag to see what happens, to see if that rectifies the situation or not. They are quite specific about calmag not being necessary, so I don’t want to recommend it. Anyway, that’s a great idea about a post explaining germination and early feeding in coco, I will look into it, thanks. All the best with this project, you’r certain to earn a great deal from the experience. Happy growing!

Crip 2019-08-31
Thanks again 🙂 i will report how it went out. I have another question. When do you start to feed your seedlings? Should i give nutrients from the beginning or should i wait until they lose their colour? And how much fertilizer in ec/ppm should i add? My fertilizer says 1ml for seedlings/clones and this is an ec around 0.6-0.8ec. But i cant find if they mean from the beginning after they show their first leafs or cotyledons or if i should wait till they have one to three true leafs. Its hard to find detailed informations how to feed seedlings in coco or how to water the coco right because everyone use different methods. I will follow the watering guides you told me. I like your Website very much ❤️ I want to make the best out of it. I had great results with biobizz soils and i want to get the coco grows as perfect as the soil plants. First i thought coco is like growing in soil and only i have to add fertilizer from the beginning and watch how the plants look and increase/decrease the feedings but its not as easy as i thought 🙂 but i want to work with coco and its fun to learn more about growing in different medium/soil or hydroponic. I will use coco now for some years and if i get the most out of it i will try some different hydroponic systems. Thanks again for your fast response and sorry for the bad english and hope you understand what i mean ? Greetz Crip

Tim Alchimia 2019-09-02
Hey Crip, hi again! Please don’t worry about your English, it’s really great and I understand you perfectly! Those EC levels sound about right for seedlings. Normally, in soil, I wouldn’t feed seedlings till they had 3 sets of true leaves, but as you point out, plain water can be a problem in coco, so maybe cut the fertiliser dose in half for the first few irrigations, and see how the plants react before giving them the full dosage. As far as the watering goes, too much will cause as much of a problem as not enough, so aim for about 20% runoff each time, that ought to be enough to flush away any excess salts without causing problems. But remember that there’s really only so much you can learn from a guide or instructions. Conditions will differ from growroom to growroom, and everything from the genetics being cultivated, to the temperature and the humidity, will affect the plants’ demand for water. This means you’ll need to be reactive to what the plants are telling you, at least until you get your particular grow space and genetics “dialled in”. It seems to me that you’re going about this the correct way, by analysing any problems and doing a bit of experimentation until you find out what works for you.

Crip 2019-08-29
Ok thank you ☺️ i will water them only with 150ml now. I have another question. I used canna coco before and i found the coco was too fine so i switched to ugro coco and i had no problems with the canna coco with germination. Only that i watered too often. I find the particle size with ugro coco better its more airy i would say. I start the seeds in paper towel method and after the root is 1/2cm long i transplant into the coco. But this time the seedlings had burnt leafs and i think it was the salt in the coco that causing the leaf burn. I hydrated the ugro rhiza and my hands started to dry out after i filled my pots with the coco. The only thing could be that its high in NaCl/sodium chloride that causing the burnt leafs and my dry hands after handling with the coco coir. What should i do so my seedlings dont get this problems the next time? Should i flush the coco with osmosis water and germinate the seeds? Should i flush it with some fertilizer and plant the seeds for germination into it? I think fertilizer in the germination is not good but i read if you flush the coco with pure water it will change the buffers and causing calmag deficiency in the early stage ? not sure what i should do. I will try with some seedlings to find out if its the salt in the coco and will try to flush the coco with nutrients and germinate two seeds. Another two seeds i will germinate where i flush the coco only with osmosis water. And another two i use the coco without flushing and only water it to keep it moist The ec was 0.6 out of the bag/brick coco and i didnt flush just hydrate the coco and set the seedlings into the coco with a small amount of water so the seedlings have enough moisture.

Tim Alchimia 2019-08-30
Hey Crip, thanks for the comment, it’s good to hear from you again. Yes, it sounds like you’re right and maybe the Ugro needs a bit more of a rinse than just simple rehydration, although I wouldn’t overdo it, as you may end up washing away the mycorrhizal fungi, which would defeat the object of buying Ugro Rhiza in the first place! I think your suggestion of trying a few different experiments to find the cause is a great idea and the best approach to properly understanding the problem. You may find that it’s only a problem during germination and the early stages of the plant’s life, in which case you could try thoroughly flushing a small amount of the Ugro coco, just enough to germinate the seeds and keep the seedlings going for a week or two in a small container, until the seedling is strong enough to handle a higher EC, when you could transplant it to the normal (un-flushed) re-hydrated Ugro. Alternatively, since you already know it works well for germination, you could use that for the early stage, transplanting to Ugro Rhiza for growth and flowering. I hope that helps, let us know how you get on, please. All the best and happy growing!

Crip 2019-08-17
Hi i think i watered my seedlings too much in coco and the coco is waterlogged. Can you help me a little bit? I thought if i only water the coco/plants after the coco dry out the ec would get a huge spike and this could burn my roots so i watered it daily in a 0.5l pot. You say only 100ml for the plants but would this not lead to root burn because the coco is too dry and this damage the roots? I was feeding an ec for my seedlings around 0.6-0.8ec that what the feeding chart said but i watered the complete 0.5L pot every day with about 2-300ml of nutrient solution. I did many grows on biobizz soil and want to try something different and use coco now and the information about coco is huge and every person/grower/Website says different things how to feed/water coco.. I got to a website and this guys feed their seedlings every day in the first three waterings and increase the watering to three time per day after week one? The seedlings have poor root development and slow to no growth. The website this guys also had very small plants and their plants were more than a month old.. My plants in biobizz were three time as big as their coco plants. I think that the problem is too much water for young plants/seedlings. But im not sure if it damage the roots if i let it dry out.. Cant find any article about growing in coco which are right because everyone says different thinfs about growing in coco coir.. My humidity/temperature is dialed in because i did grows in soil for long time so the problem must be with my watering practice in coco or the nutrient strength i use for my seedlings. Greets

Tim Alchimia 2019-08-19
Hi Crip, thanks for your comment and questions. Yes, you’re definitely watering too much which will have negatively affected root development due to lack of oxygen. The idea is to have only a bit of runoff each time you water and to allow the substrate to dry out a little bit between waterings, but not to have it dry out completely, there should still be moisture present when you water again. it’s an equilibrium, if the roots get too dry it will damage the plant but remember that if the roots are constantly waterlogged they can’t grow and will quickly rot, leading to poor plant growth and eventually death of the plant itself. Personally, if I was using a 0.5l container I’d be watering around 50-100ml each time and increasing the frequency of irrigation if I saw that the coco was drying out too quickly. You really need to observe the substrate properly and act accordingly, rather than watering a set daily amount regardless of the condition of your coco and the plants. Watering seedlings too much too often is a common mistake, when plants are small they don’t drink or eat anywhere as much as when they’re fully grown, so irrigation amounts and frequency will need to change in relation to development. If it takes more than 2-3 days for the substrate to dry out then you need to decrease the quantity of nutrient solution and conversely, if you see the plants are drinking it all up in a day, you can increase the amount or the frequency. I hope that helps, all the best and happy growing!

What are the main aspects to keep in mind when growing cannabis with coco coir? In this post we tell you more about this interesting growing medium, f

How to Grow Cannabis in Coco Coir

Table of Contents

Are you interested in growing cannabis with coco coir? Coco coir is a highly productive growing medium for cannabis that gives the experience of growing in soil, but many of the benefits of growing weed in hydro, including fewer bugs and faster growth.

A lot of cannabis growers have started using coco coir in their garden, but there isn’t a lot of information about exactly how to use coco coir for cannabis. It can be confusing since coco coir usually comes in dehydrated bricks with no instructions.

Coco seems almost tailor-made for growing cannabis… as long as you follow basic instructions.

What is Coco Coir?

Coco coir is made of ground-up coconut husks and works surprisingly well as a medium for growing plants. Roots love it. Coco is also more environmentally friendly than peat moss (one of its main competitors), and coco is slowly replacing peat in many soil potting mixes.

Note: “Coir” is officially pronounced “coy-er” but I’ve noticed most cannabis growers say “kwar” (rhymes with “car”).

Coco coir is a versatile growing medium which can be used by itself or mixed with other ingredients. It’s often included in soil potting mixes to help correct compaction and loosen the soil while still retaining plenty of water. For example, Fox Farm Coco Loco is a great choice for soil growers who want some of the benefits of coco.

However, this tutorial focuses on coco growing that doesn’t involve any soil or non-inert ingredients, in order to achieve the fastest growth. You’ll learn how to grow with a coco/perlite mix and provide nutrients in the water. This root environment creates thriving cannabis plants.

As long as you remember to water your plants with nutrients as directed, coco plants tend to be hardier than plants in other grow mediums. You typically won’t get bugs like in soil, or root rot like in hydro. It’s rare for a coco grower to run into major problems that prevent them from getting to harvest when they follow these directions. Because of that, I believe coco is one of the best grow mediums for new growers. Plus, you’ll learn almost all the skills you need to grow in soil or hydro in the future. Coco gives you a great base of knowledge for growing cannabis that will serve you well even if you branch out to other grow mediums.

Cannabis Plants Thrive When Growing in Coco Coir!

Why Use Coco Coir for Growing Cannabis?

  • Feels Like Growing in Soil – Coco coir is a soilless growing medium that gives the experience of growing in soil. Plants are kept in regular pots, and growers simply water their plants with nutrient water. In most ways, coco coir can be treated basically the same as soil for growing cannabis.
  • Great for Plant Roots – Coco coir tends to promote healthy and fast root development compared to other potting mixes. It holds onto moisture and nutrients, yet also has a light texture that gives roots access to oxygen, too. This makes plants less likely to experience symptoms from over or under-watering.
  • Good for the Environment – Unlike peat, coco coir is sustainable for the environment. It also doesn’t have to be replaced every grow. Instead of breaking down like peat, coco coir is slow to break down and can be used more than once after a good rinsing.
  • Does Not Attract Insects – Coco coir does not make a good home for many garden pests that affect soil growers. Cannabis growing in coco coir are much less likely to be attacked by pests or bugs.
  • Plants Grow Faster than Soil – Coco gives a lot of benefits of hydroponics, which causes plants to grow fast by providing nutrients to the roots in the most easily accessible form. Plant roots don’t have to go out and search for nutrients, saving the plant precious energy. But growing directly in water can be complicated. Coco coir gives many of the benefits of hydro with a soil experience. This results in a quicker harvest and bigger yields for you as the grower.

Which Pre-Made Coco Mix to Get?

Although you can re-hydrate coco bricks at home, a pre-made mix takes out all the work! I highly recommend choosing a mix that contains both coco and perlite such as Mother Earth Coco Mix (70% coco / 30% perlite for growing cannabis. I’ve grown with Mother Earth at least a half dozen times and always get great results. Another pre-made coco mix I’ve tried that works great for growing marijuana is Roots Organics Coco Soilless Mix.

Cons of Growing Cannabis in Coco Coir

  • Must Provide Nutrients from the Beginning – Coco coir is an inert growing medium with no inherent nutritional value, so growers must provide nutrients and manage pH throughout the grow. However, this is also the case for many soil growers as well. Unless starting with composted super soil and using high-quality water, most soil growers end up having to add nutrients and manage pH just like with coco coir.
  • You Need a Cal-Mag Supplement – Cannabis plants grown in coco coir tends to need more calcium compared to other growing mediums, so usually, a standard “Cal-Mag” supplement is needed to make sure plants get all the calcium they need. These contain calcium as well as magnesium (which is needed for your plant to be able to use the calcium properly). Two great Cal-Mag supplements for cannabis are CaliMagic by General Hydroponics or CaliMagic by Botanicare. If you’re using a different nutrient company, chances are they have their own version of a Cal-Mag supplement. Whenever using any supplements, it’s a great idea to stick with the same company as your base nutrients in order to prevent the chance of unexpected interactions between two different brands.
  • Coco coir usually comes in dry bricks, so the bricks have to be re-hydrated before you can grow plants in the coir (explained below, it’s actually really easy). However, if you don’t mind spending a little bit more, there are pre-made mixes with coco coir that are formulated specifically for plants like cannabis.

Coco coir holds onto a lot of moisture but also holds onto more air than similar materials, so your plant roots get the oxygen they need to thrive. When mixed with perlite, it provides an ideal amount of water and air for cannabis roots. Coco coir drains well so plants are less likely to get overwatered, but it also holds onto nutrients so you use less fertilizer.

Once your plants are in a good coco coir mix, you just add nutrients, water and light to get happy plants.

Although growing cannabis in coco coir is becoming increasingly popular, one of the problems is that there’s not enough free information to help new growers know what to do. It’s only a few simple steps get your coco coir mix in tip-top shape, and this tutorial will show you exactly how to do it.

Which Nutrients for Coco Coir?

When growing cannabis in coco coir, always use nutrients made for coco coir or hydroponics. Most growers also benefit from adding a “Cal-Mag” supplement, which is a common gardening supplement that provides extra calcium. Learn more about which nutrients you should use for growing cannabis in coco coir.

There are pre-made coco coir mixes, but they are usually more expensive than the cost to make a mix yourself. A pre-made mix is heavy like soil because it’s already been hydrated with water. This makes pre-made coco coir mixes expensive to ship, and heavy to carry around. If you’re willing to rehydrate your coco at home, you can skip paying a premium for water.

Everything you need to make your coco coir mix can be sent discreetly to your house. You just need some coir bricks and an airy bag of perlite which can be bought at any garden store. With this method, there’s no lugging a huge bag of potting mix home, or paying for shipping to have it delivered.

This tutorial will show you how to re-hydrate coco coir bricks and mix with perlite to create a rich, cannabis-friendly potting mix. I will also share some hints about growing cannabis in coco coir and how to take care of your plants for the best results.

If you follow these instructions, you will end up with 9-10 gallons of potting mix. I used this to fill four 2-gallon pots plus six solo cups, which is a perfect amount of soil for me to grow 4 plants.

Ready to start your coco coir tutorial? Your garden will thank you for it!

Coco Coir Rehydration Tutorial: What You Need

Make It Yourself (Instructions Below) or
Buy a Pre-Made Coco Coir Mix!

Mother Earth Coco Mix is a highly recommended pre-made coco coir mix for growing cannabis. However, many coco mixes work great for growing marijuana, including FoxFarm Coco Loco and Roots Organics Coco Soilless Mix.

The following tutorial makes about 10 gallons of potting mix. Double the recipe for 20 gallons!

For this tutorial, I used two bricks of a standard 650g Coconut Coir Brick. Any similarly sized bricks from a reputable company will also work.

I used “Nature’s Footprint” Coco Coir, but any 650g Coconut Coir Brick will work great!

I have used Shultz, Espoma, Black Gold, and even Miracle-Gro brand perlite. Any 8-quart bag of perlite will work. Perlite can often be found in garden stores or the garden section of places like Home Depot and Lowes. I normally advise against all things Miracle-Gro, but their 8-quart bag of perlite is okay for this tutorial if you can’t find anything else. But remember, never use Miracle-Gro soil or their standard nutrient formula!

Any bag of horticultural perlite from any manufacturer will work for this tutorial!

I use a 10-gallon fabric container from Mad Farmer (basically a Smart Pot by a different company) because it’s sturdy, has handles and will stand up on its own after adding coco coir. ​ You could use a 10-gallon Smart Pot, two pillow cases stacked inside each other, or any other fabric container that lets water through and is tough enough to hold 5 gallons of soil.

Here’s the 10-gallon fabric pot & 5-gallon bucket in a bathtub

Note: You also need access to water and a drain for this coco coir tutorial.

Before You Get Started

Run your finger nails over a bar of soap . This adds a layer of soap under your finger nails, which will prevent coco coir from getting stuck under your nails. Save yourself the time it takes to clean your nails after you’re all done!

See What You’re Making
Makes about 10 gallons of potting mix

This will make about 10 gallons of potting mix, just enough potting mix for…

2 x 5-gallon containers

OR 3 x 3-gallon containers plus a little extra

OR 4 x 2-gallon containers plus extra

OR any setup that uses about 10 gallons of potting mix

Note: I hydrate the two bricks one at a time in the 5-gallon bucket because the 5-gallon buckets are easier for mixing in perlite, and the whole process goes by in less than a half hour anyway even if you do bricks one at a time. If you wanted, you could hydrate both bricks at once in a 10 gallon container, but that’s too heavy for me to work with 🙂

How to Rehydrate Coco Coir & Mix in Perlite

1.) Gather all materials and place everything near your tub (or wherever you’re going to rehydrate to coco coir bricks)

2.) Line inside of 5-gallon bucket with fabric container.

The inside of the bucket should be lined all the way to the top, and you need to have enough extra to be able to easily grab the top so you can lift it up later.

3.) Put the first coco brick inside the liner

4.) Fill the bucket halfway with water.

Optimally, you can add a Cal-Mag supplement and pH this water to 6.0 before soaking. This can help make sure your coco coir has extra Calcium and also help it get into the right pH range right from the beginning.

Honestly though I often use water right out the tap. You’ll be adding Cal-Mag and setting the pH later, but the “best” way is to start supplementing your coco coir now, and it definitely may save you time and trouble later.

You’ll see the brick almost instantly starts getting soft once it makes contact with the water.

5.) Wait 8-10 minutes or until the coco coir gets fully hydrated.

If you stick your hand in and there’s no more hard parts left, then you’ve waited long enough. The coco coir should feel soft all the way through the bucket. You can mix the slurry around with your hands to get it to break up faster if you’re in a hurry.

Some growers let it soak longer, especially if they’re using pH’ed water that’s been supplemented with a Cal-Mag supplement, giving the coco more time to “take in” the good stuff. But I usually wait about 10 minutes and go to the next step.

6.) Pull liner up and out, letting water drain .

First let the majority of the extra water drain out into the bucket, then place the liner in the tub or on the ground so it can continue to let water drain out slowly.

7.) Pour half the 8-quart bag of perlite on top of your coco coir

8.) Mix in perlite with hands

Make sure to mix everything thoroughly, and check around the sides too, where you’ll often find pockets of perlite or straight coco coir. It’s really easy and quick. Just stick your hands in and mix everything together until it looks even all the way through 🙂

This moving gif should hopefully give you an idea.

After mixing, your potting mix will feel light and kind of soggy. You should end up with something that looks like this.

9.) Fill your containers with potting mix

One batch makes about 5 gallons of potting mix, so it should easily fill a 5-gallon container. You could also use it to fill 3 x 2-gallon containers or 2 x 3-gallon containers, though in both cases you’ll be a little short.

Don’t worry if the mix feels soaking wet, it will dry in the fabric pots once you have a fan blowing over them in your grow tent.

10.) Repeat steps for second brick of coco coir & remaining half of perlite bag

Now you fill the rest of your fabric containers and possibly solo cups for seedlings.

Note: If you do use solo cups, make sure to cut holes into the bottom so that water can drain out after you’ve watered your plants. Always test to make sure water runs through cup freely. If you have a hard time filling up an empty solo cup with water because it’s running out the bottom, you have added the right amount of drainage.

Recap: Do you have everything you need to make your coco coir mix? You’ll need the following items to complete the tutorial above.

  • 2 x 650g coco coir bricks
  • 8-quart bag of perlite
  • 10-gallon fabric pot
  • 4 x 2-gallon Smart Pots (or a total of about 8 gallons)
  • 5-gallon bucket

The above tutorial should leave you with about 10 gallons of potting mix.

Or Buy a Pre-Made Coco Coir Mix!

How to Grow Cannabis in Coco Coir

Now that you’ve got your mix ready (or purchased a pre-made coco coir mix), it’s time to start growing!

This isn’t the only way to grow cannabis in coco coir, but this is what I do and it works great. It directly follows the tutorial above for rehydrating coco coir and creating a coir-perlite potting mix.

Which Nutrients for Coco Coir?

Any quality cannabis nutrients made for hydroponics will work well as long as you also use a Cal-Mag supplement.

I personally like the General Hydroponics Flora trio plus Calimagic​ (a Cal-Mag supplement) for growing in coco coir.

This is a tried and tested nutrient system for any type of hydroponic growing including coco coir. You can actually follow their nutrient schedule listed on the included nutrient schedule; it’s formulated for plants like cannabis.

Note: After adding nutrients (or even if you’re giving just plain water), always pH your water to 5.5-6.5 before giving it to your plants. This is important!

Like nearly all cannabis nutrients, the included schedule is aggressive and can burn your plants if given with every watering. No matter what nutrient system you’re using with your coco coir, I recommend giving plain water every other watering to prevent nutrient buildup.

Whenever using liquid nutrients, you will need a way to test pH so your plant roots are able to easily absorb all the nutrients they need. I use a simple General Hydroponics pH test kit. Learn more about managing pH here:​

How much Cal-Mag should I use for coco coir?

Give Cal-Mag at full strength alongside your nutrients for at least two weeks at the beginning of your grow. You may also add Cal-Mag with your other other nutrients if needed throughout the grow, though you may want to give it at lower doses.

What Else Do You Need?

  • Grow Lights
  • Plant Containers – I like fabric pots
  • Solo cups (optional)
  • Rapid Rooters (optional)

If you followed the above tutorial to make your own coco mix, you’ll have about 10 gallons of potting mix. This can be used to fill 2 x 5 gallon pots, 3 x 3 gallon pots, or 5 x 2-gallon containers.

I recommend larger containers for larger plants and to water less often. I recommend smaller containers for smaller plants, and when the grower is willing to water more often.

Step-by-Step Grow Cannabis Coco Coir Tutorial

1.) Germinate seeds in fresh Rapid Rooters on top of the moist but not soaking coco coir in your solo cups. Some growers will plant their seeds directly in the coco coir, and that works well, too. You can also place the Rapid Rooters in a tray, making sure there’s a very shallow pool of water at the bottom to keep them moist. Fresh Rapid Rooters give some of the best germination rates, but of course there’s other ways to start your plants. Learn about other ways to germinate cannabis seeds here:

2.) After seedling grows first set of “real” (serrated) leaves, water with nutrients at normal seedling strength , and add a regular dose of Cal-Mag (Calimagic). Keep giving water until you get about 20% runoff out the bottom of the solo cup. The first set of leaves are round, but the second set are serrated and pointy. Once you see those leaves, it’s time to water your seedling with nutrients.

3.) Maintain seedlings. Some growers will put their Rapid Rooters in solo cups, while others put their seedlings directly in their final container. Either way, your job is the same. Make sure your seedlings get plenty of light while making sure that it’s never too hot for your seedlings. Place your hands where your seedlings are and wait 10 seconds, if it’s too hot for you, it’s too hot for your plants.

  • Continue to water plants at full seedling strength of the included nutrient schedule for the General Hydroponics Flora Series plus Cal-Mag.
  • When watering, keep giving water until about 10-30% extra runs out the bottom. Then don’t water again until the top inch or so starts feeling dry to the touch. If you notice water is not draining out, you need to fix that right away. Water should be able to drain freely soon after you start watering.
  • Wait until the seedling has grown 3 sets of leaves…

3b.) If you started in solo cups, you should transplant to bigger containers once the seedlings have grown about 3 sets of leaves. Once your seedling has grown 3 sets of leaves, it’s time to transplant to a bigger container!

Dig a small hole in your coco coir containers so there’s room for the new seedlings. Take a butter knife and carefully slide it all around the edges of each solo cup, then carefully transplant your seedling into your bigger coco coir containers.

4.) Maintain vegetative plants until they are half the final desired size.

Cannabis nutrients tend to have schedules that give too high levels of nutrients for proper growth. If you’re using the custom nutrient schedule I created for you above, you can simply follow the instructions. But if you’re using a different nutrient system, I encourage you to start providing all nutrients in the water at half strength.

Continue to water plants with nutrients with 10-30% extra runoff. Continue to always adjust pH water to 5.5-6.5 before giving it to plants.

  • If desired, this stage is when you start plant training (I recommend waiting a few days after the transplant to make sure plant isn’t stressed before starting any training).
    Note: If you are growing auto-flowering plants from seed, it’s recommended you don’t use any plant training techniques besides LST.
  • If you notice the lower leaves are starting to yellow, and the yellowing seems to be climbing up the plant from the bottom, it probably means you have a nitrogen deficiency. Look at the nitrogen deficiency page to make sure. If you have a nitrogen deficiency at this stage, it means your plants need higher levels of nutrients. If so, increase your nutrient levels slowly, watching closely for signs of nutrient burn (which means too high levels of nutrients). Remember that yellow leaves will likely not turn green again, so don’t look to old leaves for recovery. What you’re looking for is making sure the problem isn’t still spreading to different leaves. It’s also likely that any improvement may take a few days after you provide increased nutrient levels. So don’t keep upping your dose until you’ve given your plant a few days to a week at the new level!
  • If you have any other problems besides a nitrogen deficiency, consult this page:
  • Once plants are half the desired size, switch to the flowering stage (if you have auto-flowering plants, they will automatically switch to flowering after about 3 weeks).

​ This stage lasts until your plant is about half the size you want it to be in the end. After your plant has grown half the desired size, it’s time for the next step.

5.) Switch to the flowering stage. With regular plants, you do this by changing your light schedule to 12-12 (12 hours of light, plus 12 hours of uninterrupted darkness). With auto-flowering strains the switch to the flowering stage happens without you needing to do anything. Learn more about cannabis life stages and switching the flowering stage.

6.) Maintain flowering plants until they are ready to harvest. Care is basically the same as before, except during the flowering stage it becomes more important to control temperature and humidity than ever. Cannabis plants are much more finicky in the flowering stage, and it’s easy to trigger problems if you aren’t controlling your environment. Watch over plants closely, and make every effort to expose all bud sites to light and a breeze. You can still train plants by gently bending too-tall colas, but avoid any major training once the plant has started making buds.

7.) Harvest buds when ready. This tutorial will explain everything you need to know about when to harvest your plants:

Here are some additional nutrient suggestions for growing in coco coir:

Nutrient Picks For Growing in Coco Coir

Often when growing cannabis in coco coir, it is helpful to supplement with extra Calcium and Magnesium as calcium deficiencies & magnesium deficiencies are relatively common in coco coir. There are many supplements that provide a boost of these nutrients, and pretty much all of them will work fine. A commonly seen one called “Cal-Mag” by Botanicare works well (and is pretty inexpensive), and so does “CaliMagic” from General Hydroponics. Coco coir is an excellent growing medium as long as you maintain the pH between 5.5 – 6.5 and make sure the plants have enough calcium and magnesium.

Any quality cannabis nutrients made for hydroponics will work well for growing in coco coir as long as you also use a Cal-Mag supplement.

I personally like the General Hydroponics Flora trio plus Calimagic​ (a Cal-Mag supplement) for growing in coco coir. This is what I use for my coco coir grow. You can follow the nutrient schedule provided by GH as long as you provide plain water every other watering. Or…

You don’t need any other nutrients to grow marijuana; the Flora trio + Cal-Mag will give your cannabis plants what they need to flourish through the vegetative and flowering stages.

For the easiest coco coir growing, get a smart pot (pot made out of fabric – they work perfectly for growing cannabis and have good drainage).

Ever wondered how to use coco coir blocks to make a cannabis-friendly rich potting mix? This tutorial breaks it down… ]]>