Sourcing Coco Coir for Cannabis: A Supplier Audit
Hydrate a block of cheap coco and a flip-flop might turn up in it.
That is not a figure of speech. It is what Rx Green’s own team has pulled out of dehydrated raw coco blocks that arrived at their Denver facility. “There have been times when we’ve hydrated the dehydrated blocks we get, and we find pieces of flip-flops in there,” Rx Green CEO Gary Santo said on the Beard Bros media stage at the IgniteIt Cannabis Capital Conference. “Plastic. Candy wrappers. You name it.”
The host, Bill Levers of Beard Bros Pharms, a cultivator since 1989, did not blink. He had been pulling netting, wire, and baling string out of his own coco for years.
Nobody puts that in a product listing. Substrate gets sold on price per bag, on water holding capacity, on air porosity. It rarely gets sold on where it came from, who handled it, and what got compressed into the block along the way. Which is a problem, because that is the part that can quietly cost a grower a room.
Here are six key questions operators should pose to any coco supplier, including Rx Green. They only make sense once a grower knows what happens upstream, so that is where this starts.
Ready-To-Use coco grow bags on a pallet at the Rx Green Technologies warehouse
First, the truth about coco
Coco is a byproduct of the coconut industry, which is part of why cannabis plants grow well in it. Being a byproduct is also the root of the problem: nobody grew that husk for cannabis cultivation. What happened to it afterward – who dried it, on what surface, or how many hands it passed through – is invisible unless somebody in the chain went and looked.
“When you actually go out to India, and you see how a lot of this is harvested, you realize you really do need to get to the actual farms,” Santo said. “When you’re dealing with a lot of intermediaries, a lot of different people who look at the stuff, touch the stuff, step on the stuff, it’s amazing what you might find.”
Much of it is processed outdoors, which is not disqualifying by itself. “It is what it is. A lot of it’s done outdoors,” Santo said. What matters is whether those people test their own material, and whether anyone downstream checks their work. Plenty do not. “There are a ton of folks out there who will promise you everything, and then when you get the actual product, and you start testing it, the variability is off the charts.”
Variability is what causes operators real issues, because it can mean the pallet that ran beautifully in May and the pallet that stalled a room in June came in on the same purchase order, from the same vendor, at the same price.
Rx Green is not narrating this from a comfortable distance. The company had to work on this for years. “We’ve had our moments. We’ve stumbled with those in the prior years, but we spent the last three years really rebuilding that supply chain,” Santo said. That rebuild is why the six questions below are the ones Rx Green now asks of itself.
A sample of Rx Green’s 100% Pure coco coir being tested for quality
The coco supplier audit
These are the six questions to put to any vendor. Rx Green answers all of them about itself at the end, so that customers can hold the company to the same standard.
1. Does the supplier buy direct from the farm, or through intermediaries?
Why it matters. Every hand between the coconut and the finished bag is a chance for contamination and for variability. Intermediaries also break the feedback loop. When a lot goes wrong, a broker cannot say which farm it came from, so nothing gets fixed, and the same problem arrives again the next quarter.
A good answer sounds like: they name the region, they have been to the farms, and they can name who processes their material.
Red flag: vague geography. “It comes from Southeast Asia.” A supplier who cannot say whose farm it came from cannot fix a bad lot, only replace it.
2. At how many points does the supplier test?
Why it matters. Most suppliers who test, test only the finished product. A single test at the end of production indicates whether to ship a lot. It does not say where the problem entered the process, which is the information necessary to stop it from recurring. It is also worth understanding where heavy metals in coco actually come from before accepting a vendor’s assurances about them.
A good answer sounds like: testing on receipt, during production, and after production. Santo describes Rx Green’s in exactly those terms: “We test it when we get it, we test it throughout production, we test it after production.”
Red flag: “It’s tested.” Passive voice, no specificity, no answer about who did the testing.
3. Will the supplier show the COA for the exact batch being bought?
Why it matters. A certificate of analysis for some lot, at some point in the past, is marketing. A certificate for the pallet on the grower’s dock is quality control.
A good answer sounds like: they send it without friction, and it covers the testing panels Santo names: “ heavy metals, pesticides, fusarium. All the testing you want to see, the microbials, all the way up and down the stack.” They should also be able to show the work behind the claim, the way Rx Green published its clean coco trial and the case study that came out of it.
Red flag: one COA on the website that never changes. Or a delay, because a supplier who tests seriously already has the document.
One caveat, from Santo rather than from marketing: the panel is necessary, but it is not the last word. “I don’t want to get into a battle about what my lab PhD thinks should be happening in your garden. I care what’s happening in your garden.” A grower can put their hands in the medium and know something no panel shows.
4. How long has it been sitting in the supplier’s warehouse?
Why it matters. Almost nobody thinks to ask this, and it is the one Rx Green would ask first. Hydrated loose coco is wet and biologically active. It is not a canned good, and treating it like a shelf-stable dry good changes what shows up on the dock. The same applies once it reaches the grower, which is why Rx Green publishes storage guidelines rather than assuming a pallet keeps forever in a warehouse.
A good answer sounds like: a real number, offered without being pressed. Rx Green’s is a deliberate ceiling: “We generally don’t want to carry inventory for more than 30 or 60 days. We want you to deploy this stuff as fresh as possible, because it’s loose, hydrated coco.”
Red flag: they do not know, or they treat deep inventory as a feature. A supplier sitting on a year of stock is optimizing their working capital, not the grower’s crop.
5. Does it arrive buffered and ready to run, or is that the grower’s job?
Why it matters. This is a question about labor, and about who absorbs the risk of inconsistency. Compressed coco is cheap to buy. What that savings purchases is work: someone hydrates it, charges it, buffers it. Every one of those steps is a chance for a grow team to introduce variance from room to room, and that variance never appears on the invoice for substrate. Rx Green has made the fuller case separately, both for ready-to-use bags versus compressed and for what they do to grow room efficiency.
A good answer sounds like: it arrives ready. As Santo puts it, “You don’t have to fluff it or hydrate it, you don’t have to charge it, and it comes buffered already.”
Red flag: the buffering spec gets described but never documented. Or, alternatively, it’s not buffered at all, but just washed. The state of the coco, and the COA behind it, should be available on request.
6. Can the supplier build it to the room’s requirements?
Why it matters. A substrate that suits a flood table is not the substrate for a dry-back-heavy room. A supplier with exactly one recipe forces the grower to adapt an irrigation strategy to that warehouse.
A good answer sounds like: they will adjust the blend. Rx Green builds ready-to-use coco grow bags with as much or as little perlite as a room wants. While the standard go-to’s are 100% pure and 70/30, custom blends like 50/50, 80/20, and even 90/10 are available upon request.
Red flag: one SKU, take it or leave it.
Why suppliers are getting these questions more often
“You’re seeing a turn towards more big ag type standards,” Santo said. “People are starting to press more on their COGS. What’s it cost to grow that gram? And the more we normalize as an industry, the more those typical metrics are going to be pressed.”
In that world, consistency beats a hero yield, and growers have already learned to tune out yield claims: “every time you talk to them about yield, that’s the one thing they always discount.” What survives scrutiny is dependability, because a substrate that behaves identically pallet after pallet is what makes automation, crop steering, and any honest COGS math possible at all.
The downside is also asymmetric. A grower carries a crop for three months from veg through flower, finishes it, and only then discovers a problem. “You’re not only losing a lot of money, but you’re also losing a lot of time.” A few cents saved per bag does not come close to covering that. Clean inputs are a critical and under-appreciated element at any operation.
Rx Green’s own answers to the audit
Rx Green wrote the list, so it goes first.
| The question | Rx Green’s answer |
| Direct from the farm? | Yes. “We’ve cut out a lot of the middlemen in the process. We now deal directly with some shops out in India to get our product to our standards.” |
| How many test points? | Five. On receipt, throughout production, and after production. |
| Batch-level COAs? | Yes. Heavy metals, pesticides, herbicides, fusarium, pythium, aspergillus, other microbials, available on request. |
| Inventory age? | A 30 to 60 day target, by policy, because loose hydrated coco should reach the grower fresh. |
| Buffered and ready to run? | Yes. No hydrating, no charging. |
| Built to spec? | Yes, including perlite ratio, with minimum order quantities. 100% pure coco or 70/30 coco-perlite are standard options. |
Current sizes and pricing information are included on the loose coco and Ready-to-Use grow bag pages. Growers who want to put the six questions to a person instead of a webpage can get in touch with the Rx Green team. Rx Green’s field team includes current and former growers with decades of experience, and they visit cultivators whether or not those cultivators buy from Rx Green. Santo’s standing instruction to them: “Don’t go in there with the answers. Find out why they’re doing what they’re doing. There’s a reason.”
Cannabis plants in late flower growing in Rx Green’s loose fill coco coir
Frequently asked questions
Where does coco coir come from?
Most coco is a byproduct of coconut harvesting, processed in countries including India and Sri Lanka (southeast Asia is not a country). Rx Green sources directly from reputable growers rather than through intermediaries, and ships from its Denver facility across North America.
Can coco coir be contaminated?
Yes. Coco is frequently handled and dried outdoors, and passes through multiple intermediaries before baling, so physical debris can end up compressed inside the block. Batch-level testing and certificates of analysis are how a supplier finds out before it reaches the rooms.
What testing should a coco coir supplier provide?
Certificates of analysis covering heavy metals, pesticides, fusarium, pythium, aspergillus, and microbials, at the batch level. Buyers should ask where in the process the testing happened, not just whether it happened. Rx Green tests on receipt, throughout production, and after production.
What is buffered coco coir?
Buffered coco has been pre-treated so that calcium and magnesium occupy the binding sites that would otherwise pull those nutrients out of the feed. Ready-to-Use bags arrive hydrated and buffered, so they can go straight into a room without a separate hydration and charging step.
Can coco coir be reused?
Some growers do it successfully, but it takes a tight, well-documented SOP. It typically isn’t worth the time to reuse and instead, should be composted or disposed of after harvest, as coco is already repurposed from sustainable coconut agricultural waste.
Does the age of coco coir matter?
Hydrated loose coco is a wet, biologically active product rather than a shelf-stable dry good. Rx Green targets a 30 to 60 day inventory turn so material ships and arrives fresh, and publishes storage guidelines for once it is on the grower’s site.
Is coco better than rockwool or peat?
It depends on what a grower is running. Rx Green has compared both directly: RTU bags versus rockwool and peat moss versus coco. Of note is that of the three, only coco is an environmentally friendly, sustainable product. Whichever a grower picks, the six questions still apply. In most cases, the answer is yes.
Related reading
As Seen In
