coco soil mix cannabis

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…

Growing Weed in Coco Coir

Growing weed in coco coir is a great way to to produce high quality marijuana for new and experienced growers alike. In this coco coir grow guide we’ll teach you everything you need to know to grow weed in coco, including a list of materials you’ll need, nutrients, and a how-to guide for growing marijuana plants in coco that will yield very impressive results every time.

Materials needed to grow weed in coco coir

If you’re starting out and looking to grow weed plants in coco you’ll need to purchase the following materials. This list includes the coco coir medium and containers, amendments to improve aeration and drainage, and supplemental materials used in the growing process.

  • Quality coco coir medium (premixed bags are simplest, coco bricks are more economical)
  • Perlite (increases drainage which is good for strong roots)
  • Rinsed gravel or marble rocks, clay pellets, etc. in bottom of container to facilitate drainage (optional)
  • Plastic saucers or other container to catch watering runoff
  • Cloth grow bags, plastic grow bags, air pots, nursery pots, or even a 5 gallon bucket with drain holes will work
  • 5 gallon bucket (to mix nutrient solution)
  • Stirrer (large plastic spoon, etc.)
  • Digital pH meter such as Bluelab or Hanna (required to ensure proper acidity level of nutrient solution)
  • Ph down (to get nutrient solution to necessary Ph range of 5.8-6.0)
  • Ph up (in case you overdo the Ph down)
  • Small shop vac (helpful to suck up watering runoff, and also to dry-vac to keep a clean grow area to reduce pests)

These young weed plants are growing in coco coir in 5 gallon cloth grow bags.

More experienced coco growers may invest in additional nice-to-haves like automatic watering timers and drip systems to reduce the amount of day-to-day work to maintain your plants. Make no mistake, growing weed takes a lot of effort. But it’s also extremely rewarding. And getting down to manually water your plants is especially good for newer growers as you’ll be able to more easily spot insect issues, nutrient deficiences, mold formation, or other problem signs.

In addition you’ll need to set up the right environment. This includes setting up your light-proof grow room or pick a grow tent, ensure proper air circulation, adequate ventilation, and choose the best lighting option for your setup.

Containers for growing plants in coco coir

Suitable containers for growing plants in coco coir include fabric pots, air pots, plastic pots, or plastic grow bags. Fabric containers make great coco pots because they allow oxygen to more easily reach the root zone. Fabric containers, aka “smart pots,” come in many sizes. 1 gallon fabric pots are great for small seedling or clone transplants. Transplanting multiple times into larger containers helps ensure a nice root spread.

For most indoor growers 3 gallon or 5 gallon pots are a good size. Plan to allow 1 week of vegetation time per gallon to ensure your roots fully grow out in the container. For large plants with very long veg times, 7 or 10 gallon coco pots are needed. Outdoor growers should buy the huge bags, which accommodate the larger root system that comes with many months in the vegetation stage.

You can realistically grow marijuana plants in coco coir pots of any material, even using 5 gallon Home Depot buckets with a few holes drilled in the bottom for drainage. Keep in mind that if you’re reusing plastic grow pots purchased at a local nursery or home store you need to first sterilize them with a bleach solution to ensure you don’t introduce unwanted pests to your new coco weed grow.

Coco coir bricks vs. bagged coco coir

There are two different forms of coco that are commercially available: coco coir bricks and bagged coco coir.

The main difference is that bagged coco is typically already buffered, hydrated, and ready to use right out of the bag. Coco coir bricks are generally compressed, dried out, unwashed, and potentially unbuffered. You’ll need to prepare coco coir brick in advance: breaking it up, washing it well, and then buffering it to ensure that the coconut fiber will be ready to go. For new users, coco coir bricks are a bit more work and if it’s your first time or for small grows you should go with a reputable brand of properly buffered, bagged coir.

If you’re planning to run a lot of plants or are looking to purchase your coco from Amazon, you will want to go with the more compact, lighter bricks. Canna coco bricks or another high quality coco brick are your best bet – avoid the cheapest ones that you can find online. And make sure you prepare those coco coir bricks properly or you’ll run into nutrient issues later on.

Why is buffering needed for coco coir?

Coco coir pith is naturally high in sodium and potassium. Because of this commercially available coir is treated by soaking in a calcium buffering solution. This helps leach out any salts. Because coco coir is naturally rich in potassium, this can lead to magnesium and calcium deficiencies when it is used as a media to grow marijuana plants.

Because of this you will need to supplement Ca and Mg using products such as Cal-Mag Plus, Calimagic, or others. Learn how to use Cal-mag for growing weed in coco coir.

Preparing coco coir for marijuana plants with perlite

Coco fiber holds a lot of nutrient solution, so it tends to be to damp by itself. To properly prepare coco coir for weed plants you need to increase aeration with amendments such as perlite or vermiculite. We like to use coco and perlite in a mix of 70% coco and 30% perlite. This allows it to dry out nicely in between waterings to encourage strong root growth.

Adding 2 inches of clean gravel to the bottom of your fabric pot or other container will allow for drainage. Bagged gravel can be purchased inexpensively at Home Depot or other garden supply stores. Make sure to rinse bagged gravel several times before using until the water runs clear.

If you’re trying to root clones in coco you can increase coco/perlite ratios to 60/40, this should help force the roots to grow quicker as they reach for water.

The best coco coir nutrients

The best coco coir nutrients for growing weed are designed for growing weed in coco fiber. Realistically you use any hydroponic nutrient line in coco, but some work better than others. It’s not a bad idea to try a few to see what gets you the best results for the lowest price, as nutrients can get expensive. Most coco coir nutrients for growing marijuana are salt-based coco fertilizer which allows the inputs to be immediately available, and there are some organic or veganic options for cannabis available as well.

Canna Coco

Canna Coco nutrients are a proven method for growing marijuana in coco and consistently yields good results. We’ve used Canna Coco’s nutrient line for years with great results. We’ve found it to be one of the best nutrients for coco. The full Canna coco line consists of Canna A & B which are used equally in varying amounts throughout the grow cycle. Amendments include Canna Rhizotonic (a rooting stimulator), CannaZyme (enzymes to boost plant health in coco) CannaBoost (a flowering enhancer), and PK 12/13 (a phosphorous and potassium booster during flowering).

When running Canna Coco you’ll also likely need a calcium and magnesium supplement such as Botanicare Calmag Plus or CaliMagic, Fox Farm Gringo Rasta Cal-mag or Bloom City Cal-mag when growing marijuana in coco. You can get the best prices on Canna nutrients by ordering from Amazon, and some local hydro shops near me will match whatever the current lowest Amazon price is which is cool.

General Hydroponics

General Hydroponics nutrient trio is a 3-part nutrient line that is suitable for growing weed in coco coir. General Hydroponics Flora Grow, Flora Bloom, and Flora Micro are cheaper to run then the Canna line and tons of growers swear by GH. They come in some combo packs.

Don’t forget your CalMag supplement, Calmag Plus or the GH CaliMagic combo, or else you will likely see Ca and Mg deficiencies.

Fox Farms Coco Nutrient Trio

The Fox Farms nutrient trio consists of their three-part hydro nutes: Grow Big, Tiger Bloom, and Big Bloom. Grow Big is used in the vegetative growth stage, replaced by Tiger Bloom once you see the first signs of bud development, generally a week or two after flipping lights to 12-12. Big Bloom is used throughout both growing cycles.

Fox Farms makes a number of other products to enhance their basic trio (such as the dirty dozen starter pack), but if you’re just starting out you can begin with the Fox Farms coco trio and still see great results.

House and Garden Nutrients

The House and Garden nutrient line consists of Coco A + B, Roots Excelurator, Bud XL, Algen Extract, and shooting powder. It’s not cheap. But it’s made just for coco grows so you’ll get good results.

Whether your results are worth the added cost isn’t something we can answer since we’ve never run this line. But if cost isn’t an option this line will get you some nice buds for sure. As always, invest in a cal-mag supplement as well.


The Vegamatrix nutrient line consists of veganic nutrients that can be used with coco coir. Veganic weed growing takes organic growing to the next level, using only non animal-sourced organic ingredients. Vegamatrix was started by Kyle Kushman, a former High Times editor, breeder, and grower.

The Vegamatrix nutrient line consists of Grow, Bloom, Boost, Prime Zyme, Hard-n-Quick, FTB, Amp-it, and Big-n-sticky. Multiple Cannabis Cup winners have used the Vegamatrix line. There’s a lot more bottles to consider with this line, but it’s the only veganic nutrient for coco coir that we’re aware of so if you feel you need to ditch the chemical nutes to get what they claim produces the best tasting weed then go for it.

DynaGro Nutrients

DynaGro nutrients consists of Foliage Pro and Bloom. I’ve never used it, I tend to lean towards one of the more coco-specific options. But a few growers we’ve spoken to have run DynaGro with suffiecient results.

Make sure to mind your calcium and magnesium, as with any coco nutrient you’ll likely run into issues if you don’t use a cal-mag supplement.

Botanicare Coco Nutrients

Botanicare Pure Blend Pro Grow and Pure Blend Pro Bloom are used for veg and flowering, respectively. Many growers are familiar with other Botanicare products such as Cal-Mag Plus and Silica, both of which we’ve had success with over the years.

The Botanicare Pro Grow and Pro Bloom line is made for hydroponic systems, soil, and coco according to the label. It can be bought in a combo pack as well. Having never used it, we can’t say if its one of the best nutrients for growing weed in coco coir.

Coco coir watering schedule 101, How to water plants in coco coir

With coco you’ll water plants until 15-20% runoff occurs. This provides fresh nutrients and oxygen, with the runoff removing any nutrient salts that may build up in the medium.

Coco can be watered by hand, or by connecting an extendable watering wand with a small pump. Never let the plants sit in the runoff, use a small shopvac to suck it up or you can set up a drainage table to draw away the excess solution.

When to start feeding seedlings in coco

Coco can be used throughout the entire grow process, from seed planting or clone rooting and for transplanting during vegetation, straight through the final flush at the end of flowing. Make sure to maintain proper nutrient levels depending upon the stage of growth, you need stronger nutrients during mid to late flower. More on that below.51,

And make sure to maintain the proper ph for growing weed in coco, around 5.8–6.0 range. Use a Ph meter. Don’t guess at it. Marijuana needs a slightly acidic medium in order to properly absorb nutrients, and improper Ph leads to the majority of issues that new growers face when using coco.

If you want to learn more about this you can read about the best Ph for growing in coco, including how to lower Ph correctly and how to fix Ph issues in plants grown in coco.

Coco coir pH: the best pH for coco coir nutrients

It’s important that you monitor your coco coir nutrient solution for pH to ensure that your weed plants’ roots can properly take in the fertilizer you’re feeding them. The correct coco coir pH is around 5.8 in vegetation and 6.0-6.2 in flowering. Learn more about the proper pH level for coco as well as maintaining the optimal PPMs for coco to avoid nutrient burn.

Getting an electronic pH meter is a must, you’ll use it every time. You could opt for the drop test pH kits if money is a concern, but if you’re serious about growing weed in coco coir then the pain in the butt factor makes the electronic pH meter pretty much a requirement.

Best method for flushing plants in coco

The best method for flushing plants in coco coir is to use plenty of clean, pH-balanced water. To properly flush cannabis in coco you’ll need to water about 3-5x your container size. Aim to flush for about 7-14 days before harvest to properly starve your plants for maximum bud quality. You can use automated watering systems, watering wands, or you can even hand water coco to flush it. For first-time coco growers with a few plants the hand watering method will suffice, but for larger grows watering with a pump from a large reservoir will reduce effort and speed things up. Learn more about how to flush marijuana plants.

Advantages of growing weed in coco coir

Coco offers the advantages of hydroponic growing: fast, vigorous root growth and plant development with precise control over nutrition.

Growing marijuana in coco coir is great for new growers since the coco medium holds water so it can be more forgiving than other hydroponic methods. It is resistant to insects or other pests and if watered correctly will resist mold and root rot.

This coco grower is using 2″ of gravel for drainage below a mix of 75% coco amended with 25% perlite.

Coco Coir FAQs

What is coco coir made of?

Coco coir is a growing medium made from fibers from the husks of coconuts. Coco coir has a high lignin content that makes it longer-lasting, holds more water, and does not shrink off the sides of the pot when dry allowing for easier rewetting. Due to it’s ability to retain moisture it makes a great substrate for all types of plants, including our dear friend cannabis. Coco is an inexpensive growing medium and uses the natural byproduct of commercial coconut production, so it’s environmentally friendly.

Coco coir vs. soil

Growing in coco coir is similar to growing in soil so it’s a great transition into hydroponics for new growers. In soil grows the plants’ root system gets its nutrition from the soil. In coco grows, the plants’ roots uptake the nutrients directly from the solution held in the coco substrate. Coco tends to be more forgiving then other hydroponic grow methods, and it allows for the explosive plant growth seen with hydro feeding. Unlike soil, plants grown in coco coir react quickly to changes in the nutrient solution, which allows you to quickly correct issues like pH problems or nutrient deficiencies. Due to this, it’s important you maintain proper pH and ppm levels to avoid problems.

Can you get coco coir at Home Depot?

Some Home Depot stores sell coco coir. Typically Home Depot sells coco coir bricks, bagged coco isn’t offered. Be careful if you buy coco coir at home depot though – make sure you look for the pre-buffered kind. If you’re planning to grow marijuana with coco coir bricks that aren’t buffered you’ll need to do this yourself or your nutrient levels will be impacted.

If you cant find buffered coco at HD you may want to seek alternate vendors, such as you local hydro shop. Or try Amazon, where you can get 5 Plantonix organic coco coir bricks for under $20.

One of the issues with buying weed grow supplies at Home Depot is their staff isn’t able to assist with grow questions, and they likely won’t know coco pest from peat moss. I’ve overheard employees there telling customers to consider using prebagged Miracle Grow for cannabis, which isn’t a good option. Miracle Grow is primarily composed of peat moss, and while its readily available at home depot it isn’t the equivalent to coco coir.

Can you find coco peat at Lowes?

Similar to Home Depot, if available the coco peat at Lowes is often going to be unbuffered coco bricks. Bricks of coco are light to ship, easy to store, and have good shelf life – all things that benefit Lowes and other home improvement box stores. But you’re better off buying bagged, pre-buffered coir from a reputable company like Canna or Fox Farms.

Can you buy coco coir on amazon?

Coco coir on amazon is usually the brick type, but the low prices and better selection make it a much better option that Home Depot or Lowes. Dobt go for the lowest price bricks you can find, look for a quality brand and make sure it is washed and buffered. Amazon doesnt sell bags of pre-buffered coco coir at reasonable prices due to high shipping costs, so if you want bagged coco coir bypass Amazon and go to a local hydroponics store.

Peat moss vs. coco coir – what’s the difference?

Spagnum peat moss is a natural material harvested from bogs. It has the ability to hold a lot of water, and is a primary ingredient of many potting soil blends you’d see at stores like Home Depot. Since there’s only a limited amount of peat bogs and the peat takes a while to form, coco coir is more environmentally sustainable than peat. While peat moss can also be used to grow cannabis and as a soil amendment, using a coco and perlite mix is a better option for growing marijuana. Coco coir is often called “coco peat” but it is not true peat.

Can I mix coco coir and vermiculite to improve aeration?

Vermiculite is a hydrous phyllosilicate mineral that expands when heated, forming layers that trap air. However when you add water, the air gets displaced which means it is no longer able to aerate the growing medium you mix it with. Because of this coco coir and vermiculite are not a good combo to make a substrate for growing weed. You’re better off using perlite to aerate coco coir instead if vermiculite.

Can worm castings be used with coco coir?

Worm castings are often used by organic growers to supplement their soil. When growing in coco coir worm casting substrate mixes in theory will provide organic nutrition to the grow medium. But in soil grows the plant’s root system needs to get its nutrition directly from the grow medium, whereas in coco grows the coir medium is used to suspend a hydroponic nutrient solution that feeds plants directly. Nutrition from worm castings or other organic amendments wouldn’t be immediately available in hydro grows. And adding organic additives like worm castings can also be a habitat that encourages insects. Because of this, it doesn’t make much sense to use worm castings in coco coir.

Is growing in coco coir organic?

Organic coco coir nutrients exist, but most standard coco fertilizer products are salt-based. Organic fertilizers require time to break down when used in soil so that they their nutrition is readily available to the root system. So if you’re looking to run an organic coco grow for cannabis, select an organic hydroponic nutrient strain rather than adding organic amendments. In general though you’ll find most nutrients made for coco coir are not organic. If organic cannabis growing is a priority for you, consider instead using a substrate such as an organic super soil.

Is coco coir a hydroponic grow method?

Coco coir is a hydroponic method since the marijuana plants’ roots get their nutrition directly from the nutrient solution you add to the substrate. Coco coir hydroponics is a much more forgiving method than other hydro methods such as direct water culture (DWC) since the coco is able to hold enough excess solution that you van likely miss a day and not dry out you roots. Pump-driven hydro methods can be catastrophic if the pump fails – the roots can immediately dry out. for new growers watering coco is similar to the soil watering they’re already used to for their gardens or houseplants.

Since the root system gets the oxygen it needs from the nutrient solution you won’t need to let the coco grow medium dry out between waterings as you do in soil. Some coco growers use very small containers and water multiple times per day to grow very large plants, which is easier if you use an automated watering system. If you’re hand watering a 3 gallon or 5 gallon fabric pot you can plan to water daily to get the maximum benefit of coco coir hydroponics. Initially after transplanting into coco you may want to reduce waterings to allow the roots to grow in search of water – if you overwater at this point the roots will have no reason to grow since the plant will be getting what it needs. Big roots equal big fruits, so it’s important that you get your rooting system is as strong as possible before you switch the plant into flowering.

What is the best coco substrate recipe?

We’ve tried a number of ways to mix coco substrate, but have seen the best results with a 70/30 mix of coco and perlite to provide aeration. For rooting clones or seedlings we go with a 60/40 mix of coco coir to perlite, since overly damp substrate will not encourage root growth. Coco substrate recipes can include organic amendments like worm castings, bat or bird guano (turds), but that isn’t ideal. Putting organic elements can introduce odors as well.

Is there a coco coir potting mix that comes with perlite already added?

There are a few commercially available coco mixes with perlite already added, including Mother Earth coco with perlite and Hydro Crunch. This is helpful for small home grows or first time users. But it’s very easy to mix up your own. You can get a giant bag of perlite at your hydro shop for around $30 that will last for many runs. Just remember to take precautions against breathing in perlite dust, which will damage your lungs. Wear a respirator when mixing your coco substrate, and wet down the perlite first with water to reduce fine particles that go airborne when you move it around.

What is the best coco coir for growing marijuana?

Most manufacturers will tell you they sell the best coco coir. They can’t all be telling the truth. We’ve always had good luck running Canna coco, but there are others that will work just as well. Look for bagged coco that is washed and pre-buffered.

If you use coco bricks purchased online or at stores that don’t typically move a lot of grow supplies such as Home Depot, Lowes, or Walmart, avoid the lowest price options from knock off brands. This is especially true when purchasing coco bricks online – don’t bite at the absolute lowest cost option. Typically they’re cheaper because they cost less to produce, and that translates into a lower quality coir substrate for your plants.

How to pronounce coir

The proper way to pronounce coir in the U.S. is “coy-yer”. It’s a bit different in the U.K. If you want to hear a sound clip of how to pronounce coir, check out the coir pronunciation examples on this Cambridge Dictionary page.

What are coco coir mats for hydroponics?

Coco coir mats for hydroponics are made from coconut fibers that are bound together by latex. Coco coir mats can be used for hydroponic ebb/flow tables. Ebb and flow uses pumps to flood nutrient solution on the roots at regular timed intervals. When used with ebb and flow systems, the coco coir mats allow the cannabis plants’ roots to grow through to under the mats, so that they can access moisture that remains between flood cycles.

Coco coir mats are different than the bagged coir used in containers. A commercially available example of coir mats are the CocoTek Mats sold by General Hydroponics.

How is coconut coir made?

If you’re wondering how to make coco coir you should know that coco coir is not something you can easily make yourself. About 90% of coco coir is produced in India and Sri Lanka. It is made by extracting the fibers from the husks that are left over after coconuts are harvested. Due to this is is a very sustainable growing medium. But unless you happen to live near a coco farm it’s easier to get the pre-buffered bricks.

Learn to grow killer weed in coco coir. Coco is a great choice for new growers and experienced growers alike. Coco offers the benefits of hydroponic root feeding for fast, robust growth. In this article we'll show you everything you need to know to begin growing like a pro.