Coco coir is the substrate of choice for approximately 30% of marijuana growers, for the following reasons:

  • Coco coir costs about the same as premium potting soil or Grodan rockwool, but costs about 10-20% less than premium soilless mix.
  • Coco coir has excellent porosity, water-holding, and rehydration properties.
  • Coco coir is biodegradable.
  • Coco coir of uniform density, porosity, particle size and chemical characteristics is more reliable and controllable.
  • Organic and hydroponic feed programs work well in coco coir.
  • Coco coir manufacturing is less harmful to the environment than manufacturing of other marijuana substrates.

Seeing these benefits, you might be asking why doesn’t every marijuana grower use coco coir. One reason is these benefits are available only if you’re using the highest-quality coco coir, but most brands of coco coir are inferior in ways that harm marijuana plants and make life difficult for growers.

Growers try inferior brands of coco coir, find that it causes cultivation hassles and crop problems, and abandon it. These problems include:

  • Coir that contains too much dust, debris, or other materials that make the substrate too dense, with a tendency to waterlog and drown roots.
  • Coir that creates bewildering problems for growers trying to implement ideal timing and methods for their fertigation programs.
  • Coir loaded with sodium and potassium, which interferes with feed program, often causing magnesium and calcium deficiencies along with other problems.
  • Most brands of coco coir must be used with hydroponics nutrients made specifically for coco coir. However, in our experience, these often-expensive nutrients aren’t engineered properly. They don’t provide maximal benefits in coir, and they can cause even bigger problems if you try to use them in non-coir substrate or in water culture.
  • Many brands of coco coir aren’t manufactured, graded, cleaned, buffered, sterilized, shipped or stored properly, creating inferior substrate material that’s bad for cannabis roots and plants, and may contain pests and/or pathogens.

The bottom line is that marijuana growers can benefit from using coco coir, but only if they find the highest quality version of it.

We’ve spent several years studying and growing with almost all the commercially available coir brands, including Canna, Atami, Sunshine Advanced, Botanicare, Roots Organics, and Bush Doctor. We’ve done the same with hydroponics nutrients brands that are supposedly made to handle coir’s unusual characteristics.

What we’ve learned is that almost all coir brands have problems, and that so-called coir-specific fertilizers don’t work well in coir or non-coir substrates.

Another problem is that many coco brands come in raw form, such as compressed, unbuffered bricks. You have to unbrick, uncompress, wash, and buffer these coco brands yourself, which is a lengthy, annoying process that can easily go wrong.

After conducting many crop tests with coco coir brands and seeing way too many problems, we came up with a set of standards for what we’re looking for in a coir substrate:

  • Manufactured by a company focused on making and marketing coir substrate.
  • Manufactured by a company that has at least one legitimate horticultural scientist who has major, functional control over the sourcing, refining, manufacturing, storage and handling of the company’s substrate.
  • Coir that is brown in color, with a slightly reddish tinge, and has been aged at least six months.
  • Coir with suitable air fill porosity to facilitate oxygenation and moisture/nutrients transport so roots don’t drown.
  • Coir with ideal electrical conductivity (EC), cation exchange (CE), and pH for facilitating nutrients absorption.
  • Coir that doesn’t contain much if any coir “dust.” If there’s too much dust (and most coir brands have too much), the coir is too dense, lacks adequate oxygen-holding capacity, and may create waterlogged roots.
  • Coir that’s properly washed and buffered so you don’t need to use coir-specific fertilizers or do any pre-use adjustments.
  • Coir that doesn’t have added perlite or other materials. Coir manufacturers add such materials as fillers to inferior coir to increase its porosity.
  • Coir made by a small, boutique, connoisseur company with a team of professionals dedicated to grower success and satisfaction, and who have proprietary knowledge and experience, making them experts in using coir specifically as a marijuana substrate.
  • Coir made by a company that provides grower technical support to marijuana growers to ensure that the growers know how best to use their substrate.
  • Coir that is routinely tested by the manufacturer to ensure its chemical traits and buffering are ideal for cannabis.
  • Loose coir, not bricked or compressed coir, that can be used out of the bag without adding perlite, buffers or anything else other than water and nutrients.
  • Coir sourced, manufactured and brought to market with as little ecological damage as possible, and with no worker exploitation.

With these requirements in mind, we did a forensic investigation into the horticultural coco coir industry. We eliminated coir companies that don’t make their own coir, but merely outsource its manufacture. We eliminated coir companies that sell compressed, bricked, dusty, contaminated, dirty coir.

We eliminated companies that weren’t transparent and friendly in their grower support and in providing details about the sources, manufacturing standards, buffering and other traits of their products.

It got to the point where we’d talked to every major and minor company that sells branded coco coir to the grow shop/hydroponic marketplace, and eliminated all of them.

Then we heard from industry insiders about a coir company called California Substrates. After lengthy conversations with the company’s very helpful team members, and testing their coir product, we verified that their coir and their company meets our very rigorous standards.

One primary foundation for our trust in California Substrates is that their company’s coir manufacturing procedures and standards are controlled by a skilled agronomist with more than 30 years in the agricultural and horticultural industries.

California Substrates’ agronomist Mark Wittman specializes in coco coir, and has international experience in all facets of coco coir production, processing, and use. He has two agriculture-related college degrees and has been in charge of coir research and development for companies in Australia & North America. Mark also has his own farm.

Mark has designed and set up multiple coir manufacturing facilities in Sri Lanka, India and Vietnam. He’s used soil, scoria, peat, rockwool and coco as growing media and has been working with coco as a growing media since 1998.

His experience setting up and advising agricultural facilities throughout Asia and advising various commercial agriculture operations gave him the expertise and motivation to design what we believe is the perfect coco for marijuana growers who want maximum feeding capability and ease of use.

The superiority of California Substrates coco coir starts at its manufacturing facility in India, where Mark has partnered with a highly-respected agricultural company.

“It takes approximately 200,000 coconut husks to make a container of coir substrate,” Mark explains. “There needs to be enough coconut trees in an area to have that many husks available on a regular basis, and it has to be far enough away from salt water so salt contamination doesn’t get on the husks. You need sufficient roads or rivers for transport to the factory.  From there you need a massive clean water supply for washing the coir.  And there needs to be reasonably practical and cost-effective transport to a seaport for shipping.”

Most coir companies put profits first when it comes to sourcing coconut husks, washing them, processing them into substrate, and partnering with people in foreign countries where coconuts are sourced and handled to make coir.

In some cases, workers and businesses in developing countries are exploited by foreign coir manufacturers. The unfortunate workers toil for very low wages in hazardous conditions.

In contrast, Mark and California Substrates emphasizes fairness and equity. That’s why Mark went to India looking for teamwork partner group that could meet his company’s rigorous standards and proprietary coir manufacturing protocols, and also feel like part of the California Substrates team, creating pride and quality control in the Indian agricultural and processing facility that creates California Substrate’s coir.

“We use clean water, free of heavy metals and biological contaminants. Our factory is set up to keep ground-dwelling animals and birds from contaminating the coco during aging and processing. We carefully heat treat our coco before bagging to kill any pathogens. We also test a number of times during aging and processing to monitor the progress of the CE, pH and EC properties. We also test it when it arrives in North American to ensure that its qualities are exactly what growers need,” Mark says.

California Substrates coco coir meets our overall criteria, and is physically and horticulturally superior to any other coir on the market, for the following reasons:

  • California Substrates uses a proprietary buffering process to nearly completely change the substrate’s cation exchange (CE) characteristics. Inferior coco coir’s CE is high in potassium and sodium and low in calcium and magnesium. When coir CE is low in calcium and magnesium and high in potassium and sodium, the coco absorbs calcium and magnesium from your feed program, leading to calcium and magnesium deficits that severely harm your marijuana plants. Mark explains: “Instead of slapping a band aid on coir’s problem of high sodium and potassium levels like other companies do by rinsing it with calcium nitrate, we take the time to buffer the coco naturally.”
  • Mark’s proprietary buffering process gets rid of coir’s overload of potassium and sodium and its calcium/magnesium deficit. His finished product is high in calcium and magnesium and very low in potassium and sodium. This means you don’t have to use coir-specific fertilizers, or calcium/magnesium additives in your feed program, saving you time, hassle, and money.
  • California Substrates coir is free of fine dust and engineered to leave plenty of space for oxygen, facilitate uniform movement of water and nutrients throughout the entire root zone, and avoid conditions such as waterlogging that lead to root rot.
  • Root rot is sometimes caused by growers pouring too much water into their root zone. But in inferior coco coir and other substrates, it also happens because the substrate is poorly engineered and lacks air porosity. Most brands of coco coir contain coir dust. It’s an enemy of oxygenation, and some growers are forced to add perlite, clay pebbles or other spacers to improve substrate aeration in inferior coir.
  • Mark explains that California Substrates coir doesn’t have those problems because he uses a lengthy, time-consuming, costly process to sieve out coco dust. You get a very light, spongy and pure substrate with the optimum air fill porosity and water holding capacity that greatly reduces the possibility that you’ll drown your roots. Mark is so confident in his company’s substrate that he invites growers to do a hands-on comparison of coir brands at a local hydro store. We’ve done that ourselves, using our diverse collection of coir brands, and can affirm that Mark’s coir is the cleanest and most attractive.
  • California Substrates coco has an air fill porosity (AFP) of around 30 percent. AFP is a measure of the spaces between the substrate’s particles that water drains out of almost immediately after watering, expressed as a percentage of the total media volume. California Substrates removes almost all the coco dust from their substrate, leaving larger coir particles and more open space for aeration.
  • Unlike Canna, Botanicare and most of the other corporate companies that market coir, California Substrate was created in California in late 2014 by a team of passionate growers who strongly support the medical cannabis industry. Mark explains: “Our team is small and we are all co-owners, so when you talk to us, you’re talking to the right people. We’re easily available to all growers via email, our website, social media such as Facebook and Instagram, and telephone. Whether you’re a grower thinking about a substrate change or a hydroponics retail sales rep wanting to better understand why our coco is a superior substrate, our team is here for you.”
  • Using California Substrates Coco, you can root clones directly into the coco as it comes in the bag. There are numerous advantages to cloning directly into coco. These include reducing the need for problematic humidity domes, reducing transplant trauma, and saving money. Agronomist Mark Wittman gave us the following program for cloning directly into his coir:

Here’s how to do it:

1)  Fill a seeding tray with California Substrates Coco.

2) Wet thoroughly with reverse osmosis water.

3) Pack coco tightly into seeding trays.

4) Use a small screwdriver (or similar tool) to poke a guide hole in each coir cell.

5) Place the cutting into the guide hole and pack the coco tightly around the cutting.

6) If your cloning area has extremely low humidity, a humidity dome may be used in the first 24 hours, but it shouldn’t be necessary afterwards.

7) In 8-10 days (or slightly longer with woody cuts), your clones should be healthy and rooted. Be careful when removing rooted clones from trays, plant immediately into larger containers, and thoroughly water with a starter nutrients dose.

Take a look at the impressive root growth from a clone made using the method Mark just described…GMPcoirclone.jpg

Even if we had tested coir brands and found that the two best were exactly alike as regards their physical and chemical properties, we’d still give favor to the California Substrates brand.

Why? Because the other coir companies aren’t as responsive to customer needs. When we queried Canna, Botanicare and all those other coir brands,  we were very disappointed by their refusal to provide authentic, comprehensive details about their sourcing, manufacturing processes, quality control and how to use their coir in marijuana grow ops.

California Substrates isn’t like that. Everyone who works there is a part owner of the company, and they’ve all be exceptionally timely, pleasant, and helpful, spending hours answering our questions and explaining complex chemistry and agricultural concepts.

The stark fact is that many gardening companies make coco coir to use as a loss leader to lure you in so you buy their nutrients or other products which are far more profitable. I prefer a company that makes coco coir because they love doing it and are coir connoisseurs.

When we asked California Substrates agronomist Mark Wittman to sum up why growers should convert to California Substrates, he said:

“Many coco producers don’t sieve out the fine dust, so growers have to add perlite or hydroton to add air fill porosity so they can feed their plants more often, or they end up only feeding their plants every few days.

There are downsides to both these scenarios.  First, using aeration amendments adds cost and labor. You create more air spaces, and roots end up migrating to those air pockets…but that’s not where the water and nutrients are.

Growers who have dense substrate so they only feed every few days aren’t able to provide the best nutrition program. Think about it in terms of your own nutrition—if you only ate one huge meal every two days, how healthy would that be?

By providing smaller amounts of water and nutrients and more feedings, you’re ensuring your plant is constantly getting the optimum fertigation amounts and timing.

Another major difference with our coco is the way we buffer it.  We nearly completely change the cation exchange so the coco doesn’t pull calcium and magnesium from your nutrients solution. With our substrate,  coco specific base nutrients and Cal-Mag products are not needed.  At California Substrates we spare no expense and go the extra mile to create the perfect coco.”

Mark was kind enough to give some general tips for growing marijuana in coco coir, and he emphasized that he and his colleagues are happy to work with growers so they understand how to get the best from coir substrate.  Here’s some of his expert advice:

  • Frequent watering, including watering several times per day, is better than one large watering every few days.
  • Although California Substrates creates absolutely clean coco coir with no pathogens on-board, and some people say that reusing coir for multiple crop cycles is one of the benefits of coir, Mark says that it’s best to use a virgin coir for every crop in most circumstances. Reusing coir creates too high a risk that pathogens may have developed in the coir, and growers he’s advised have told him that reusing coir creates problems that make it worthwhile to procure virgin coir for every crop cycle.
  • Some coir companies make a big deal out of so-called organic or OMRI certification for their coir. However, when you examine the certification process and ask the companies to prove the validity and benefits of their alleged organic coir, you discover that the organic certification isn’t much use.
  • For example, the California Department of Food and Agriculture (CDFA) is attempting to develop a program for cannabis comparable to the National Organic Program. The term “organic” is a designation reserved by the U.S. Department of Agriculture for products it certifies as organic, per the terms of the National Organic Program. But cannabis is illegal under federal law, so organic marijuana grow ops can’t be certified under the National Organic Program, and the word organic can’t be used to refer to California cannabis. CDFA uses the term “OCal” to describe what it defines as “comparable-to-organic” cannabis in California. This means if you’re a commercial cannabis licensee in California, and your cannabis is produced according to OCal’s requirements, then you may be eligible to apply for comparable-to-organic certification through the OCal Program.
  • In the current OCal regulations, which have yet to be finalized, we find no mention of whether coco coir substrate has to be “organic” or not.
  • Mark says coco coir manufacturers rely on the honesty and validity of foreign organic certification agencies where the coir is manufactured. “Part of this issue is you’re trusting the people doing the organic certification, but in India the certification process can be very corrupt system,” Mark explains “If India says a coco substrate is organic, people elsewhere might accept this as an actual fact. Problem is, the system in India can be bought off.  So what does the certification mean under those circumstances?”

As readers of Growing Marijuana Perfectly already know, we rarely recommend marijuana growing products–because so many of them are bogus. We always ask grow op supplies companies if they know of professional cannabis cultivators we can talk to about their products.

That’s how we got in touch with Aries Malone, the cultivation director for the largest licensed marijuana cultivation facility in California’s Coachella Valley. Malone supervises 120 employees, has tens of thousands of square feet of grow space under his supervision, and has 34 year’s experience in the cannabis industry. 

 “I’ve cultivated in just about every substrate and hydroponics system possible, including mixing customized soils, peat moss, flood and drain, deep water culture, perlite, and Grodan rockwool. I found California Substrates eight years ago and have been using their coco for all my commercial grow ops ever since,” Aries explains.

He’s used California Substrates coco to grow dozens of strains with this Coco in a multitude of grow op environments, using a diverse range of professional nutrients formulas.

“California Substrates is the most versatile substrate ever. No matter what conditions my grow op has, this substrate handles them and gives me great success. I’ve run all kinds of feed programs, including synthetic, organic and synthorganic, and never had deficiencies or lockouts even though I run a high-ppm feed program through the entire flower process maintaining a balance of 1500 ppm throughout the entire cycle with pH between 6.0 to 6.8, and approximately 20% runoff. My runoff comes out the same 1500 as what I put in, which means my plants are uptaking everything that I feed them,” he says.

Aries describes California Substates coco as vastly superior to other brands, in part because it has been dried in ovens instead of outdoors in the sun. This makes it more porous and uniform.

He’s also very happy that he saves money and protects the environment by reusing the coir several times, but emphasizes you can only do this with California Substrates coir, which is more resilient and long-lasting than other brands.

Substrate reuse should only happen when the grower properly reconditions the used substrate after a crop cycle to totally remove pests, pathogens and old root materials, he notes.

“I use California Substrates coir from propagation to harvest. It has proven time and again to be absolutely superior to any other coir brand, whether you use it in a small personal grow op or the largest commercial marijuana growing facility. It’s the most air-friendly substrate I’ve ever found, giving me incredible roots like you see in the photo—every time I grow. Growing in California Substrates coco is like cultivating in air,” Aries says. “The company’s team are great people to work with. You can tell they’re focused totally on grower success,” he said.

If you’re using a different brand of coco coir, or some other type of substrate, it’s a good idea to contact California Substrates and see what they can do for you. If all coir companies were as professional, grower-centered and ethical as California Substrates, there’d be a lot more people using coco coir for growing marijuana. Take a look at the root ball photo from Aries’ grow op, and you’ll see what this coir brand can do for you!