Clean Coco Coir for Cannabis Research Study

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Does soil choice really impact the vitality and yield a cannabis plant produces? We wanted to know, too. There are a plethora of ways to improve plant health – from cannabis nutrients, lighting systems, seed or clone genetics – there is a lot of information and advice for a cultivar to apply to their established grow techniques.  

Deciding on a cannabis growing medium or substrate is among these choices. The Rx R&D team decided to dig in and conduct our own study, to provide our customers and industry partners with definitive results on the benefits of growing substrates for cannabis plants. 

As a result, our Clean Coco Coir Study confirms weight and THC potency are higher when cannabis is grown in a clean substrate.

  • Plants that used Rx Green’s Clean Coco growing mediums had a statistically greater stem diameter than the competitor’s substrate.
  • Cannabis buds grown in Clean Coco Coir substrate yielded more bud weight per plant. 
  • THC content in these cannabis plants was higher when grown in a Clean Coco Coir growing medium. 

Our conclusion? Growing mediums matter. Read our Clean Coco Coir research study to understand why.


Data presented by: Stephanie Wedryk, PhD, Director of R&D at Rx Green Technologies


To compare the effect of two different coconut coir substrate products, CLEAN COCO and a leading competitor (Competitor Coco), on cannabis growth, yield, and potency.


First, CLEAN COCO and Competitor Coco were chemically tested at Midwest Laboratories, a Colorado State approved laboratory.


Competitor Coco Clean Coco
pH 7.1 7.0
Soluble Salts/EC 1.2 0.28
P 12 <10
K 100 50
Mg <10 <10
Na 82 23
Ca <10 <10
CEC 24 32

Higher CEC (Cation Exchange Capacity) indicates greater ability to hold certain nutrients (K, Ca, Mg, Mn, Fe, Zn) with lower potential to lose them in runoff. CLEAN COCO has a higher CEC than Competitor Coco, ensuring greater nutrient availability. Additionally, Na in high concentrations can be toxic to plants. Competitor Coco has a higher concentration of Na than CLEAN COCO.

Next, the cannabis variety Quattro Kush was planted in CLEAN COCO and Competitor Coco. Clones were transplanted directly into coconut coir substrate and tracked through harvest for differences in growth, yield, and potency

GROWTH: Stem diameter and plant height were measured weekly upon transplant of clones until the fifth week of the flowering cycle. Canopy diameter was measured weekly from clone transplant through the last week of the vegetative cycle.

YIELD: Bud weight was measured per Colorado State compliance regulations, both directly after being harvested and trimmed, and after drying.

POTENCY: THC was measured at an approved Colorado State laboratory.



Stem Diameter was statistically greater in CLEAN COCO treatments than Competitor Coco during the flowering cycle.

Height of Quattro Kush in CLEAN COCO and Competitor Coco was statistically equivalent.

Canopy of Quattro Kush grown in CLEAN COCO and Competitor Coco was statistically equivalent.


Quattro Kush grown in CLEAN COCO yielded more bud weight per plant.


THC in Quattro Kush was higher when grown in CLEAN COCO.


Quattro Kush grown in CLEAN COCO had increased growth, yields, and potency compared to the Competitor Coco. CLEAN COCO has the potential to improve cannabis yield and potency compared to competitor brands. Our team believes that the combination of low salts and high CEC via strict quality controls led to the outperformance via the use of CLEAN COCO.

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