how to grow cannabis in coco coir

Which Nutrients for Coco Coir?

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.

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.

Cannabis Plants Thrive When Growing in Coco Coir!

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 .

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.

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

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

Step-by-Step Grow Cannabis Coco Coir Tutorial.

This moving gif should hopefully give you an idea.

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.

​ 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.

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

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…

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.

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

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

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.

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.

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

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.

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.

OR 4 x 2-gallon containers plus extra.

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.

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.

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.

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.

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

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.

We at Organic Mechanics think our Cocodelphia coco coir product is one of the best on the market. Why? For one thing, we buy our coir from just one farm in India, so our variability in quality is essentially non-existent. That farm washes the coir several times and relies on the monsoons of Southeast Asia to accomplish this. Once we have received the coir, it’s washed again as we rehydrate the air-dried, compressed coir blocks. Essentially, Cocodelphia is triple washed.

I mentioned “science” above, and it turns out “science” is a key aspect of why coco coir is an ideal medium for growing cannabis as well as other crops. Some of the properties of coir that allow crops to thrive when grown in it include:

If you’re just beginning to grow cannabis legally, you’ll want to grow it correctly. While we won’t get into the day-to-day details of cannabis production here, we will explain how to get your cannabis crop off to the best start possible. It all starts with your growing media (and we know growing media). Specifically, one growing media of choice for many growers is coco coir.

For more information about coco coir, check out the great content on the Maximum Yield site, beginning with THIS ARTICLE.

Packed with nutrients and biostimulants. It’s a formerly living thing, so it comes packed with its own set of nutrients, such as potassium, iron, manganese and zinc, to name a few. Again, you should take this into account when considering what nutrients to apply. It also contains biostimulants, which act as growth enhancers and give whatever is planted in it a boost.

The Science of Coir.

Neutral pH. Its pH is close to neutral (6), so coir can be used straightaway. Peat is acidic (as low as 3-4) and needs to be treated with lime before use. This neutrality is good because it allows the user to add the nutrient mix of their choosing.

Professional cannabis cultivators all agree that drainage and aeration are key to a successful crop. Many achieve this by using coco coir as their growing medium. Coco coir, if you’re not familiar, is produced from the humble coconut, specifically the fibrous material found between the husk and the coconut itself. This material holds water well but also allows for good drainage. (I know it’s hard to wrap your brain around being both water-holding and water-draining at the same time, but let’s chalk it up to science.) Well-draining growing media allows for good air flow, which is good for root growth. And a good, healthy root system is the secret to a great crop of pretty much anything, including cannabis.

Over the last decade cannabis production has come out of the closet, quite literally. The first person I knew to have grown his own cannabis (or marijuana or pot or whichever name you prefer to call it) grew several pots of it in his bedroom closet, hidden away from his parents. And while some folks may grow cannabis in places unseen by parental and other authorities’ eyes, at-home and/or commercial legal cannabis production is now A-OK in 18 states and Washington, D.C. with more coming on board every year.

Watch for salts. If there is a downside of coir it’s the fact that the product in its raw form contains salts. You, the end user buying coco coir products, don’t really need to worry too much about the salt level because it has been processed and washed extensively before you receive it. But if for some reason you’ve found some compressed blocks of raw coir, do know the salts need to be rinsed away or else it can harm your crops.

Our Cocodelphia is also continually tested for heavy metals, and each test result comes back clean. Don’t just take our word for it! Our customers have done their own testing and tell us it’s the cleanest heavy metal-free coir for cannabis production around. And for you professional cannabis growers out there, you know cannabis that fails a heavy metal test means a lost crop and lost profits.

Coco coir has another beneficial aspect that is good for not just cannabis but also the planet. It’s a renewable product. Coir’s water-holding-and-water-draining characteristic allows it to be a great substitution for peat moss, which is not a quick-to-renew resource. Less peat being used means less mining, which means less damage to the sensitive and diminishing peat bogs of the northern hemisphere. We came across an article in the New York Times that explains the peat and climate change situation HERE.

Cocodelphia is also ready to go straight out of the bag. Add in some other beneficial amendments such as Biochar Blend or Worm Castings for a punch of nutrition. Or plant in the bag and save yourself the time of potting.

High cation exchange rate. This allows nutrients to be stored and used as needed, except for calcium and magnesium, which coir tends to hold on to. Adjust your nutrients accordingly. A calcium and/or magnesium supplement is a must do when growing in coco coir.

Do Note! Cannabis production is not legal nationwide. While it may be legal to cultivate cannabis where you are, many states do still consider it illegal unless you possess a state-issued license. Check and abide by your state and local laws before you grow. If, however, you have the option to grow cannabis and you know you are doing everything legally, by all means, please do! And give our Cocodelphia a try while you’re at it.

What Is Coco Coir?

What Makes Cocodelphia Great.

Often, piles of coir dust were not left to decompose sufficiently and the resulting coco had a high nitrogen draw down index, this meant that under soilless cultivation, even with well balanced nutrients, nitrogen deficiencies in the early stages of growth were common.

Coco was initially seen as a replacement for peat in greenhouse production – coco does not have the water repellence of dry peat, or the low pH values . However in the early days of experimentation with coco growing substrates many problems were found due to inconsistency of the product. Many coconut sources were retted in seawater and contaminated with very high levels of sodium and unpredictable levels of naturally occurring potassium.

However while there are excellent brands of coco on the market, there are also still poor quality supplies still being sold as a growing medium and growers need to select and only use a reputable brand, preferably one which has an accompanying `coco nutrient’ formulation designed to work with the cation exchange properties of the product.

Coco, a superior growth media.

These days good quality coco has proven to be a superior growth substrate for a large number of different crops, with the advantage of being from a renewable and environmentally sound resource.

figure 6: finer grades of coco can be used to germinate seeds and raise seedlings.

There are many different types of coco products on the market. The husk of coconuts yields not only very coarse long fibres which are used to make a wide range of products such as rope, carpets, mats, brushes, basket liners and others, but between these coarse fibres is a corky substance called coir pith, coir dust, coco peat or coir peat . Many grades of horticultural coco exist and some have been specifically designed for different plants and systems. The very fine particle size of coir dust retains a high level of moisture and this is suited to seed raising and for smaller seedlings and plants. While a high moisture holding content in fine coco dust is an advantage in some situations, it can create problems with over saturation of the root zone. Grades of coco often used in slabs may consist of larger particles or `flakes’ of coco which allow a good degree of drainage and resist packing down over time as commonly occurs on substrates such as peat.

figure 3: The optimum physical structure of coco means that crops are provided with high levels of oxygenation and moisture in the root zone.

Coco substrates also had a high cation exchange capacity and retained calcium, phosphate and iron meaning these became unavailable for plant uptake until the coco had been in use for some time and had fully `conditioned’. As a result many soilless growers initially experienced problems with coco they didn’t understand. Few growers understood the degree with which the coco media was affecting the composition of the nutrient solution in the root zone and the fact that the coco provided an almost ideal physical structure for plant growth was overlooked.

figure 5: young cucumber crop being grown in high quality coco.

Different types of coco products – uses, pros and cons.

Coco fibre is also the term often used to refer to the general purpose grade of coco which is ideal for growing longer term crops under soilless cultivation . Worldwide coco is used for soilless crops such as tomatoes, peppers, cucumber, melons, aubergines, ornamentals, cut flowers and many others because the structure of the coco does not break down over the time frame these longer term crops are grown for. Thus high rates of root zone aeration and moisture retention are typical in both short and long term soilless crops and this results in high yields and good root health.

For an extraction test, a small sample of coco is taken from the growing media, (several samples should be taken and combined to give a representative sample). Then 100ml of these combined samples is measured out (coco should be damp but not overly saturated). The 100ml sample of coco is placed in a jar and 150ml of deionised (or RO) water is added and the mixture shaken 50 times. This is allowed to sit overnight to allow extraction of nutrient ions in to the water. The resulting mix is then re shaken and filtered to remove particles and the pH and EC can be measured.

However, high quality horticultural coco is now recognised as a superior growth media for soilless crops on both a small and commercial scale and many of the initial problems have been overcome by correct processing of the raw product and adjustment or pre treatment before packaging. High quality coco substrates on the market for soilless cropping have often been specifically processed for this use right from the point of removal from the coconuts, through to preconditioning, buffering and pre treatment.

figure 4: Coco is available in a range of grades from very coarse ‘orchid fibre’ seen here, to fine ‘coco dust’.

Tips and tricks when using coco.

figure 2: Coco propagation blocks being used to raise cucumber seedlings.

This means that nitrogen draw down is no longer a major problem, sodium contamination from retting in seawater does not occur, the naturally occurring potassium levels are adjusted and treatment with calcium and other ions is carried out before the product is packaged . Suppliers of high grade coco also carry out regular testing of their product to check for any irregularities in supply and to correct for these.

Loose coco placed into growing pots or containers can be easily inspected for moisture level by checking the appearance of the top of the substrate or by feeling the moisture level of the coco just below the surface, this is more difficult in wrapped coco grow slabs. The coco slab only needs to be placed in position, slits cut in the plastic sleeve and water poured in – the coco expands and can be planted out with no further effort. The disadvantage of slabs is that they need a very level surface to sit on so that drainage is even and they don’t provide the depth of growing substrate that a planter bag or pot can for larger plants.

Noguera P, Abad M, Puchadea R, Noguera V, Maquiera A and Martinex J, 1907. Physical and chemical properties of coir waste and their relation to plant growth. Acta Hort. 450: 365-373.

Always invest in a good quality , well known brand of coco designed for soilless growing and don’t be fooled by the many inferior quality products on the market. While coco from different sources may look similar, there can be large differences in the quality and this can have a negative impact on plant growth . Coco products sold in garden stores and hardware outlets often as inexpensive compressed bricks of ` garden mulch ’ are not usually suitable for soilless growers – these types of coco are typically high in sodium (an unwanted element), high in total salt content, often have not been fully decomposed, and hence have a high nitrogen draw down which can result in nitrogen deficiency even when the full strength nutrient solution is applied. Inferior coco products are also not `buffered’, `conditioned’ or `pre-treated’ to stabilise the potassium levels and boost calcium which is required to offset the tendency of coco to retain calcium. They may also contain weed seeds and pathogens . Buying a reputable brand of coco for soilless growing is an important investment in the nutrition and health of the plants and also simplifies the process of growing a great crop. Select the right nutrient product (i.e a specific coco nutrient product) to use on coco substrates. Coco growing media is not like many other soilless substrates such as rockwool which arrive pre sterilised, chemically inert with a low CEC and with a very minimal effect on the composition of the nutrient. Coco contains naturally occurring potassium which since potassium is a major plant nutrient, is considered a bonus; however this needs to be allowed for in the nutritional program of the plants. Coco also has other effects on the composition of the nutrient solution applied and levels of nitrate, phosphate, calcium, magnesium and iron may need to be adjusted to allow for these properties. There are commercial brands of specific `coco nutrient’ formulation products on the market, however it is always a good idea to select both the coco substrate and the coco nutrient of the same brand as it is likely they have been developed to work together and will give the best results. High quality coco products are likely to have been pre-treated and the accompanying coco nutrient will take this into account so that the ratio of elements in the root zone stays as optimal as possible. Select the right type of coco product for the plants being grown. There are a large range of coco products on the market and many different grades with various horticultural uses. While orchids prefer a very coarse coco `chip’, using coco for propagation and germination of small seeds requires a much finer grade which will hold sufficient moisture as well as oxygen. General purpose coco which consists of a range of particle sizes is considered ideal for many plants and is the most widely used grade for soilless production. The coarser particles help the coco substrate remain more `open’ to aeration while the finer particles hold moisture between irrigations and the combination of both these, is what gives coco close to optimum physical structure for plant growth. Remember that coco is a `living substrate’ and it should be treated as an entire eco-system which consists of beneficial microbes who make their home in the coco particles. This beneficial microbial life plays an important role in soilless systems as many fungi have a protectant effect on the plant’s root system and have been proven to suppress plant pathogens as well as other possible benefits with nutrient uptake and plant growth. While other growing substrates start out as sterile, coco is best left in its original state or even inoculated with populations of beneficial microbes such as Trichoderma. These populations of beneficial microbes in coco are to be encouraged and for that reason harsh sterilising chemicals such as chlorine bleach, hydrogen peroxide and even boiling water should not be used on coco substrates at any stage. Coco usually maintains pH within an optimal range ; however EC can build over time and should be checked from time to time, particularly under warm growing conditions where the plant may have been taking up a lot of water from the substrate, allowing the concentration of nutrients to climb. Because of the nature of coco growing media the EC around the plant’s roots may be different to that in the leachate or the solution draining from the growing slabs, pots or bags. A quick and simple `extraction sample EC test’ can be carried out on coco media to determine the actual EC around the root zone.