How much water your plants need, how often you should water, and what influences a cannabis plant´s water absorption rate. Water plays a crucial role in keeping your marijuana plant healthy. Get tips from the experts at Leafly to keep your weed plants hydrated, and learn how to flush them properly. Buy Quality Marijuana seeds at Amsterdam Seed Supply – How often should you water Marijuana Seeds? – ✓ High Quality Strains✓ Award winning genetics
How Often Should I Water My Cannabis Plants?
Knowing the right time to feed your plants can depend on many variables, so find out more below about what to consider in order to maintain the perfect watering ratio.
- 1. Factors that influence cannabis watering
- 1. a. Medium
- 1. b. Pot size
- 1. c. Pot type
- 1. d. Environmental conditions
- 2. The best way to water cannabis plants
- 2. a. Soil and coco
- 2. b. Hydroponics
- 3. Plain water or nutrient solution?
- 3. a. Feeding plain water only
- 3. b. Nutrient solution
- 4. Oversaturating the cannabis grow medium
- 4. a. Overwatering
- 4. b. Overfeeding
- 5. Top tips for marijuana watering
- 6. Best recommended heavy feeders
- 7. Cannabis crop watering faq
- 8. In conclusion
If you are new to growing Cannabis indoors or outdoors, having a thorough understanding of how frequently you should be watering or how often your plants require it can be quite difficult. There are many factors that play a huge role such as the pot size, strain, conditions, and substrate. In general, you should water when the medium is around 60-70% dry.
Below we’ll explain what you should know when it comes to watering your Cannabis plants.
1. Factors That Influence Cannabis Watering
First of all, every grower needs to understand that a question like “how often should I water?” is basically pointless because your watering schedule will depend on your own specific growing environment. There is no set way to water Cannabis plants or the best time to feed cannabis plants , or any type of house plant for that matter, however, each grower has their own set way, based on what is most practical for them.
There are multiple elements that can dictate how much water or how often you need to water your cannabis such as genetics, the phase your plant is in, growing setup and if you’re feeding with every watering or not, but the main ones are pot size, medium, and the environmental conditions.
As you may know, the substrate is where the roots will be growing, and depending on your preferred mix, it can hold more or less water which can affect the amount of water you need to water with and how long it takes for the water to evaporate. For example, if your substrate contains more perlite, it will allow more oxygenation which can increase the evaporation rate, or if it contains a lot of coco fiber it can take longer for the water to evaporate due to coco being able to retain water for longer.
Another factor that can affect how often you water your cannabis plants is the pot size because if there’s more substrate you will have to water with more water and it will take longer for the water to evaporate, obviously, this depends on the stage your plant is in. If your plant is still a seedling you don’t want to water it with a lot of water even if it’s in a 60L pot, but as it grows, you will have to water more and it will take longer for the water to evaporate (when compared to a 10L pot) depending on the conditions.
The type of pot you use, and the conditions inside the pot will have an effect on how often you will need to water your cannabis plants. There is a huge range of options available, but they are definitely not all equal. No matter what type of pot you end up using, drainage should be high on your list of concerns. Many novice cultivators fall into thinking that over drainage is a bad thing, as the plants won’t have a chance to feed properly from the water before it all drains away. This could not be further from the truth. To have the healthiest and most vigorous growth possible, you want your pots to offer high levels of drainage.
If you are using everyday plastic pots you will probably want to drill a few extra drainage holes before you start planting. It’s also a good idea to add a layer of pebbles at the bottom of the pot to help with overall drainage down the line. This stops the drainage holes from becoming clogged and ineffective. Here at FatsBuds, we recommend using air pots or smart pots, especially if you are going to be growing your weed indoors. These pots are made from canvas or fabric and allow for air exchange directly through the material which offers far better root zone oxygenation than terracotta or plastic pots.
This promotes the healthiest and widest-reaching root growth possible and allows for easier root zone temp control. These types of pots do tend to dry out a little quicker than traditional options, so keep that in mind when watering and make the necessary adjustments.
But the main factor that influences how often to water is the growing conditions. This happens because, if the humidity levels are too high it will take longer for the water to evaporate whereas if the humidity is too low, water will evaporate faster.
Also, if the humidity is too high it will encourage the transpiration process, making plants absorb more water and evaporating it faster while a lower temperature slows down transpiration and will take longer for the water to evaporate.
2. The Best Way To Water Cannabis Plants
As said above, there’s no better way to water plants, this will depend on your setup. There are several ways to water plants, either by hand-watering, having a drip irrigation system, and bottom feeding among others.
Soil and coco
Soil and coco (with any other things mixed in such as perlite and etc.) are the most common mediums and allows you to water any way you prefer.
This is the most basic way to water a weed plant. Normally you will add enough water until you see runoff. By watering weed in this instance, the growing medium will always stay well saturated, yet will never be encouraged to dry out and increase air capacity.
A very simple and foolproof way to water your cannabis plants by allowing the roots to suck the water up. This only happens correctly when the growing medium is dry enough, to cause a wicking action that will draw the water upwards to the roots.
Many growers swear feeding in this manner is the most advantageous, then again many will debate that the buildup of salts is far greater. It can also lead to mold and root rot issues if the system is not maintained to a high standard, so always be careful to drain the remaining feed water between feeds.
Drip irrigation system
A drip irrigation system is not very common amongst soil growers but it can be a great choice for coco or hydro growers. This method consists of a small hose on top of the pot that waters your cannabis plants by releasing drops of water non-stop. So to help you have an idea of how much to water and how often, here’s a small guide to help you water your cannabis properly.
Cannabis watering schedule for beginners
|Coco or Soil||≈100-200ml||≈300-600ml||≈700-1500ml||Usual amount of water + 10-20%||Every 2-4 days|
Just have in mind that this guideline was designed for plants grown in 10-12L pots and under optimal conditions, which are:
- Seedling stage – 65-70% humidity and 20-25°C
- Vegetative stage – 70-40% humidity and 20-26°C
- Early Flowering – 40-50% humidity (lowering approx. 5% each week) and 22-28°C
- Late Flowering – 30-40% humidity and 18-24°C
Your plant’s metabolism is affected by the conditions and will determine how much water your plant absorbs.
Just have in mind that even if your growing the same strain, it all comes down to your plant’s metabolism wich is affected by the conditions, so for example, if you’re growing our Wedding Cheesecake Auto under 30°C in 45% humidity, your plant will need much more water than the same strain under 25°C in 60% humidity.
Now, when growing hydroponically you need to have a drip irrigation system or any other system that waters your plants automatically. Watering using timed irrigation not only saves physical labor but also ensures the cannabis plants are fed the exact same amount, on a consistent basis. Organic growing mediums fed with drip stakes will grow much faster than when hand watering, and is replicated on enormous scales in the agricultural sector.
Cannabis watering guide for aero and hydroponic setups
|Hydro (Perlite, clay pellets, or rockwool)||100-400ppm||500-1200ppm||100-1600ppm||As close to 0ppm as possible||15min ON, 15min OFF (24/7)|
|Aeroponics||100-400ppm||500-1200ppm||100-1600ppm||As close to 0ppm as possible||5s on 4-5min off (24/7)|
So, to help you avoid overfeeding and give you an idea of how much you should feed your cannabis, here’s a table for hydro and aeroponics. Have in mind that the amount needed for soil or coco will differ depending on the brand you’re using so you should follow what they recommend.
When growing in hydro or aeroponics, it’s better to feed your cannabis by measuring the parts per million (which is basically the amount of nutrients in the water in a 1/1000000 concentration) in your nutrient solution.
Measuring ppm instead of measuring by ml/L it’s better because you get a more exact amount of nutrients, water contains a small amount of micronutrients (aka trace minerals) and due to your cannabis being directly exposed to the water, they will end up absorbing it. So when growing in either of these methods, we highly recommend measuring the pH and measuring the ppm of not only your nutrient solution, but also of the water source; Remember that water purity is very important when growing in hydro or aeroponics.
3. Plain Water or Nutrient Solution?
Hydrating a plant is one thing, however, feeding a nutrient solution is different and there are a few things to consider. The root hairs of a Cannabis plant only need to come into contact with a fine film of water to be able to tap in and extract what they need.
Feeding Plain Water Only
This is basically as organic and simple as one can be, as Mother Nature does all the rest. As all of the necessary primary and trace elements can be found in abundance inside an organic living soil, all that is required is to keep the moisture levels adequate for the living microorganisms. Compost also depends on specific temperatures and moisture levels in order for organic matter to break down over time.
Most growers who follow a nutrient feeding chart will feed a mix of different nutrients until the final few weeks. During the last part of the flowering cycle is the flushing period where plain water is fed to the plants for two reasons.
Break Down Undissolved Salts
The build-up of nutrient salts that can develop over a 10 week period or more can be quite excessive. Especially if using chemical-based nutrients that are designed for hydroponic systems.
Water is the source of life and is also a solvent in its own way, meaning the final 14 days will help wash away (aka flushing) the remaining salts increasing the flavor and quality of the ash.
Using Up The Reserve Nutrients
Even though it may seem a drastic change to switch from a maximum nutrient solution, it is necessary to starve the plant forcing it to use up all of the reserved nutrients. This is when Cannabis plants will begin to exhibit rapid deficiencies and is a sign the nutrients are being used up.
4. Oversaturating The Cannabis Grow Medium
There is nothing worse than having the best intention, but unfortunately, too much water or nutrients does not result in more growth, so overwatering or overfeeding your cannabis will have a toll on your plants.
In the event your growing medium is inadequate regarding drainage and water-retaining capacity, then the water evaporation can be very slow causing many issues to occur. Transpiration that occurs through the leaves will need to compensate for the excessive amount of water around the roots. As plants find a way of transporting water through foliage or the root zone, by oversaturating you are jeopardizing the integrity of the plant’s growth, causing stunted growth.
Also, wilting of the fan leaves is a clear indication you have over-saturated your root zone, and the plants are not happy.
This can also happen when underwatering, which is when your plant is lacking water. Even though underwatering shows the same trait, do not feed more water and allow your growing medium to air out until the pot is light to pick up. A cold and wet root zone will cause anaerobic bacteria to infect your garden and kill your cannabis. It is extremely important to keep your root zone oxygen-rich and one reason why felt pots are so popular. And when this happens, cannabis plants will fail to uptake certain much-needed nutrients if the water levels are too great.
Just like when watering in excess, feeding with a too strong nutrient solution will cause the minerals to build up and the results will be a lockout in nutrients and a line of deficiencies to begin occurring one after another. This happens because cannabis can’t use the excess minerals and they end up burning the tips of the leaves and can end up burning the whole leaf if not dealt with fast.
As the nutrient burn continues, the tips of the leaves will start to get brown, crispy, and sometimes twisted; This is very common when using bottled nutrients, that’s why it’s a good idea to look into organic feeding if you have access to them. This is where the importance of pH levels in water comes in; Maintaining pH levels in between the acceptable range (for each specific medium) is one way to avoid this kind of problem because the pH level can block the roots from absorbing the nutrients your plant needs.
So even if you’re feeding your plant properly, higher or lower pH may prevent them from absorbing them and result in similar symptoms as overfeeding but will actually be caused due to the lack of nutrients, known as underfeeding.
When your plants are suffering from pH problems or an excess of nutrients, flushing is the best way to solve your issues, and to do it correctly, you will have to water your plants with plain pH’d water.
This will correct the pH levels and wash off the excess nutrients in the medium and the roots, allowing you to start feeding your plants from scratch or correcting the pH level, allowing your cannabis plants to absorb the nutrients they need once again.
Top Tips for Marijuana Watering
So, if you’re a beginner grower here are a couple of tips to avoid having some of the problems cited in this article.
Know when to water by weighing the pot
A good way to calculate the watering ratio is to feel the weight of your growing medium when it is at the lightest with no water. This is the point your plants need to be each time before watering. By doing this you will always know when to water without running the risk of overwatering.
Use your finger to check if the medium needs more water
If you are hand watering and are not sure if the medium is wet enough, simply insert your entire finger down the side of the pot. Judge how moist or dry your finger feels and this should give you a clear indication of when next to feed.
Water plants with room temperature water
It is better to water plants with room temperature water (around 20-23°C), as cold water can cause shock and encourage a cold root zone.
Water your plants when the lights are ON or up to 30min before
Avoid watering close to lights out, as the plants will not get a chance to use it until lights are on. Humidity levels in the garden can increase and oxygen levels and temperatures around the roots will drop.
Best Recommended Heavy Feeders
For all the growers who like to give their ladies the best nutrients on the market, we have picked our 3 biggest feeders to keep you company in the grow room.
first time ever growing and got some amazing colors from this strain with low temps ran it at about 58-64 for 2 weeks and got this color
A rock-solid performer who can take heavy and frequent feeding, and she will grow big fat buds in return.
This is a resilient strain that needs that extra nutrients to be able to develop the big fat nugs so make sure you feed it properly, always keeping an eye out for signs of deficiencies.
I grew this with other fast buds strains. I’m very happy how they all grew. I use soil, 19L pots on a 20/4 light cycle. They love it.
When it comes to the biggest autoflowering cultivars around, this lady is certainly up there with extra-large yields and a big thirst.
This plant grows quite big for an autoflower and thanks to its Sativa heritage, it will need that boost when it comes to nutrients to be able to develop big and strong and be able to withstand the weight of the huge amount of buds during flowering.
I got 134g off this gal growing in 3 gal pot with 24 hours of light. i’m stoked with the result! Smells like diesel. Was a great grow overall.
Another big feeder who loves a high nutrient ratio, thanks to her Indica-dominant lineage. This strain grows quite stocky and produces huge yields, that’s why you should feed her properly, and in return, it will produce lots and lots of resinous buds and in a big quantity.
Just remember that despite being heavy feeders, you should always pay attention to any signs of deficiency and increase the nutrient dose gradually to avoid stunting growth!
7. Cannabis Crop Watering FAQ
How Much Should I Water My Crop?
While there is no exact answer to this question, with experience you will get to know how much watering your crop will need. The amount needed will be totally dependent on the stage of growth, the size and types of pots used, the intensity of the light, the cultivar, the environmental conditions, the health of the crop, and the style of cultivation. Keep in mind that it is totally fine to let the plants go without water for a day or two every now and then, and is actually recommended by many experienced cultivators. The thinking behind this is that when the roots run out of water they will spread out and go searching for it, resulting in a larger overall root ball. Remember bigger roots mean bigger plants, which means bigger yields.
How Do I Tell If My Plants Are Thirsty?
As mentioned above, a great way to tell if your plants are in need of watering is by getting used to the weight of the plants. Cannabis plants themselves don’t actually weigh that much, with most of the weight coming from the water trapped in the pot. If you pick up a pot and it seems super light, it’s probably time to feed. Another obvious sign that your crop is thirsty and ready for some water is drooping and weak plants. If your plant looks like it is struggling to hold itself up then there is a good chance it needs a feed, but proceed with caution here.
Why? Well, plants that have been overwatered will display similar signs. If you feel like you have fed your crop often enough for it to be healthy and it is still looking weak and lifeless then there is a high chase that you have actually overwatered. The best thing to do in this situation is to feel the weight of the pots and to let them dry out for a day or two to see if there is any improvement.
How Much Water is Too Much Water?
When watering cannabis plants, a good rule of thumb is to aim for about 20 – 25% of the pot size. So, say you are growing in 12-liter smart pots (which is absolutely perfect for autos) then you should aim to give the plant about 2.5 to 3 liters of feed water. Another way to judge the correct amount of feed water is the amount of runoff. You do not want to water the plants until the substrate is just moist without seeing any runoff, as this can quickly lead to nutrient saturation issues.
Every time you water your plants you want to see about 15 to 25 % of the water running off. It’s also important to be able to remove this runoff, a sitting water can lead to its own range of serious issues for your crop. Be sure that you have a system in place to easily remove any and all runoff, such as drip trays. Inclined trays work great, and a wet/dry shop vacuum can help immensely.
Is There a Timing Guide for Watering my Cannabis Crop in Terms of Growth Stage?
Again, as we have mentioned above, this is really dependent on a huge range of factors. But, as a very general guide, you can aim to water your crop in the following way:
: at least twice a day, if not three times. Seedlings prefer small, frequent waterings. Do not worry so much about seeing runoff here. plants: Daily or twice daily is the best protocol to follow if you are hand watering plants that are in the vegetative growth stage. plants: Plants that are flowering require slightly less water than vegging plants, but once a day should still work well. Some growers recommend 4 times per week, with a break every third day
8. In Conclusion
Having a reference when your growing medium is the most lightweight, is a great start point for a beginner grower to work with. Finding the balance of how much your plants are drinking as well as transpiring is a learning curve that can take hands-on experience and require multiple grows under your belt.
Once you find the perfect mix, your Cannabis plants will respond in kind, and remember less is more sometimes. And remember that if you were wondering how to water outdoor cannabis, the process is basically the same but you should be extra careful on rainy days.
For those of you who have the watering game on point, feel free to leave your tips in the comment section below to help out fellow growers!
How to water and flush marijuana plants
Like all plants, cannabis requires water in order to perform its basic functions. Water helps plants absorb nutrients from the soil and then moves up the plant and into the leaves, and without it, the plant can’t survive. But giving a marijuana plant the proper amount of water may be more difficult than you think.
There isn’t an exact science for watering a weed plant. You can’t observe the roots in most cases to see if they need water. Also, a plant is constantly growing and the climate it’s in will fluctuate, so the amount of water it needs constantly changes.
Here are some tried-and-true tips to keep your weed plants healthy and properly hydrated.
How often should you water marijuana plants?
A common mistake first-time growers make is to overwater marijuana plants. A cycle of wet and dry is healthy and necessary for the roots of a plant to grow out and reach deeper into the soil.
Additionally, roots pull in oxygen as soil dries and when soil is too wet, the plant can’t pull in oxygen efficiently and essentially can’t breathe.
Below are general estimates and are meant to give growers a rough sense of frequency of waterings; if a plant needs water and it falls outside of these ranges, water it.
|Plant stage||Water every # of days|
How to tell if a cannabis plant needs watering
The best ways to tell if a weed plant needs water is to:
- Stick a finger 1-2 inches into the soil—if it’s wet, hold off; if it’s dry, it’s time to water.
- You can also pick up a pot and feel its weight to determine if it needs water. This will take some experience—be sure to lift up your pots after watering to get a feel for how heavy they are when full of water. This will also give you a sense of what a light, dry, plant feels like.
An under-watered marijuana plant looks droopy and weak, with yellow or brown leaves; there is no strength in the leaves and they look lifeless.
Leaves of an overwatered plant look slightly similar in that they droop, except the leaves will be dark green and the leaf tips will be curled.
Note how often you water plants and write it down in a log. Get your marijuana plants on a watering schedule—as they grow out of the seedling stage, watering every two to three days is ideal.
Keep in mind that as plants get bigger, they will need more water and need to be watered more frequently.
When growing weed outdoors, you’ll need to water more often as the weather gets hotter and less often as it cools.
When you find the sweet spot between too wet and too dry, your plants will flourish.
How much should you water marijuana plants?
The amount of water your marijuana plants need depends on a few factors:
- Size of plant
- Outside temperature
- Overall health
- Stage of growth
You want to water a plant enough to soak all the soil in the pot. Water should pool up on the surface of the soil when you’re watering, and come out the drainage holes in the bottom of the pot after a couple seconds. If water sits on the surface of the soil, that means it’s too wet and doesn’t need more water.
If a weed plant is very dry, water will run straight through the soil and pot and quickly come out the drainage holes. If this happens, water the plant a little bit and then come back to it after 15-20 minutes and water it again, and maybe even a third time. This allows the soil to slowly absorb water until all of it is thoroughly wet.
Roots are constantly on the hunt for water as they grow and stretch out. As a plant gets bigger, so should the watering radius—the area around the stalk of the plant that you water. Doing this will help guide roots to the edges of the pot as they seek available nutrients in soil.
Watering too far away from the roots can create standing water, which can lead to root rot, mold, and pest issues.
Is your container the right size?
To properly water a cannabis plant, it needs to be in the correct size container, or a big enough hole if it’s in the ground. If a pot is too big, the plant’s roots can’t drink water where they don’t reach. If the roots aren’t absorbing water, water will sit in soil and take a long time to evaporate, which can promote root rot and unwanted insects and fungus.
Conversely, if a container is too small, the roots won’t be able to stretch out, which can stunt the growth of a plant. Less soil also meant you’ll need to water the plant all the time, which will add labor.
Ideally, cannabis plants should start in a small pot and progress to bigger and bigger pots as they outgrow each container. For example, you can start a seedling or clone in a 4″ or 1-gallon pot, then move on to a 2-gallon, 5-gallon, 10-gallon, and so on.
Plants are ready to transplant when a healthy root structure encompasses most of the soil and the roots aren’t bound. When transplanting, take time to look at the quality of the roots: Bright white roots with a strong, thick structure is a sign plants are getting watered correctly.
What is flushing?
Flushing is an important part of the marijuana growing process, when you stop giving a marijuana plant nutrients and give it straight water. This is done to flush out nutrients that may have built up in a plant during its life.
Flushing is done for about a week before harvest, at the end of a plant’s flowering stage when buds are almost ready to cut down.
A flush can also be done to clear plants of nutrients if they have a nutrient imbalance, such as nutrient lockout, when your plants are overloaded with nutrients and unable to absorb new ones.
How to flush weed plants
Flushing marijuana plants before harvest
The final flush should occur for a week or so before you cut down weed plants for harvesting. Water your plants with the same amount as you normally would, but only with water. This will force the plant to use the nutrients stored within it—if its nutrient reserves are not used or broken down, it could affect the quality of your harvested buds.
By looking at the trichomes on marijuana plants, you’ll be able to tell when the plants are ready for a flush—begin when they start turning milky.
Different growing mediums require different flushing timeframes before harvest:
- Soil: 7-10 days
- Rockwool and coco: 7 days
- Hydroponics: 5-7 days
If growing in amended organic soil, it is not recommended to flush plants. This is because the soil already holds all the nutrients the plant needs to thrive, and by flooding the soil you can wash away and damage the complex ecosystem that you’ve worked hard to develop.
When to stop watering before harvest
Water your marijuana plants as normal when in the flushing phase—don’t let them get too dry or too wet. Make sure not to harvest dry or wilting weed plants—they should be nice and healthy when you cut them down.
How Often Should You Water Marijuana Seeds?
After the hassle of choosing a seed and getting it to sprout then grow, another of the big questions is how often should you water marijuana seeds until they germinate. You should not water marijuana seeds once you place them to germinate in a warm moist place. If you give your marijuana seeds water very often you will drown the seedling and it won’t be able to crack out of its seed.
Now that the Marijuana seed has germinated, how often should you water Marijuana seeds?
Once it germinates though, how often you should water marijuana seedlings varies according to the temperature of where the marijuana seeds are growing, but as a rule of thumb, you should water the marijuana plant once the soil is dry. An easy way to tell is if you try and lift the edge of the pot with one finger; if it feels “light” then it’s time to water, if not then leave it a few more days to evaporate and check back often to water. Usually, when you follow this technique, it helps with the formation of trichomes on your marijuana plants during the flowering phase which is equal to dank-er flowers.
You might also find our FAQ submission How Do I Feed A Plant? useful!