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)
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.
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 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 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
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 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.
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.