Clean Coco Coir for Cannabis Research Study

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.

MEASURING GROWTH, YIELD, AND THC POTENCY

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

PURPOSE

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.

PROTOCOL

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

CHEMICAL COMPARISON OF COMPETITOR AND CLEAN COCO

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.

FINDINGS

GROWTH

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.

YIELD

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

POTENCY

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

CONCLUSION

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.

Cannabis Flushing Research Study

Is flushing your cannabis plants really beneficial for the final outcome? The effectiveness of flushing cannabis is often questioned, and there is debate about the ideal length of the flushing period. Our Rx Green R&D team conducted a study to uncover the truth behind this urban myth in cannabis growing nutrients.

The study examined the impact of various flushing durations on the taste, chemical composition, and smoking quality of the Cherry Diesel cannabis strain.

• We tested the effects of 14, 10, 7, and 0 days of flushing cannabis plants.

It’s interesting to note that even in this cannabis flushing research study, there still is no clear indication of whether you should flush cannabis plants and the impacts it has as a result.

• Rx Green’s cannabis flushing study showed no major differences in the results of flush treatments for cannabis nutrient systems.

While the range of flushing periods for cannabis is often debated, no scientific studies or research has further validated this commercial cultivation practice.

Surprisingly, this research study further proved that there is no clear indicator of when to flush cannabis plants and the impact it has on the end result.

For a more in-depth look into our cannabis flushing research study, read the complete study below.

IMPACT OF DIFFERENT FLUSHING TIMES ON QUALITY AND TASTE IN CANNABIS SATIVA L.
Data presented by: Stephanie Wedryk, PhD, Director of R&D at Rx Green Technologies; Taylor Wall, Research Operations Lead at Rx Green Technologies; Ryan Bennett, Research Associate at Rx Green Technologies

CANNABIS FLUSHING TRIAL SUMMARY

• Rx Green Technologies evaluated the effects of different flushing times on chemical profile, flavor, and smoking characteristics in cannabis flower.
• Flushing periods of 14, 10, 7, and 0 days were imposed on Cherry Diesel.
• No differences were detected between flush treatments for yield, potency, or terpenes.
• Analysis of the mineral content of leaves indicated small changes in content, specifically of iron and zinc.
• Taste test panelists tended to prefer flower flushed for 0 days.

INTRODUCTION

The taste and combustion qualities of cannabis are dependent on the chemical characteristics of the flower. During the growing cycle, management practices can influence these chemical characteristics for cannabis cultivation supplies.

For this reason, many cannabis growers implement a flushing period where only water is fed to plants in the final days to weeks before harvest. While many cultivators attest to the effects of a flush, no scientific studies have been conducted to validate this practice. Rx Green Technologies has conducted a pioneering study to assess the impact of different flushing times on the chemical profile, flavor, and combustion characteristics of cannabis flower.

CULTIVATION MATERIALS AND GROWING METHODS

Cannabis variety Cherry Diesel (Cherry OG x Turbo Diesel) was grown at the Rx Green Technologies’ R&D Facility using Rx Green Technologies nutrients, cannabis grow supplements, and Clean Coco.

Grow A & Grow B and E-Plus were fed during the vegetative stage, and Bloom A & Bloom B, E-Plus, and Bulk were fed during the flowering cycle. The first flushing period began 14 days before harvest. The other flushing periods were ten, seven, and zero days before harvest. Each flushing period was tested on 12 different Cherry Diesel plants divided into four different groups (replications) spread evenly across the flowering room tables. Flower and fan leaf samples were collected from each flushing treatment on the first day of flush and the day before harvest to quantify concentrations of essential plant nutrients and cannabis grow supplements.

After harvest, the study plants were cured before determining the final trimmed flower weight, terpene, and THC concentrations. Trim was evaluated by an extractor for THC, yield, and appearance of the extract or “wax.”

In order to assess the flavor and characteristics of smoking, samples from each flushing period were given to cannabis industry experts for a blind taste test. Each participant received a sample from each flushing time without knowing its treatment. Prior to tasting, participants were asked about their personal cannabis flavor preferences. After tasting, participants were asked to rate the sample on flavor, harshness of smoke, and ash color.

The data collected during the study were analyzed statistically to determine whether flushing times affected smoking quality, flower weight, or chemical characteristics of cannabis. Statistical data analysis allows us to quantify whether differences in the numbers are due to the treatments imposed or are the results of the natural variations observed for cannabis growing mediums.

CANNABIS FLUSHING RESULTS AND DISCUSSION

The day before harvest, visual differences in fan leaves between flushing times were apparent. Plants flushed for ten or 14 days had leaves that were more yellow, necrotic, and dry than plants flushed for zero or seven days (Figure 1a-d). The color of the 14 and ten-day flushed leaves indicates a greater breakdown of chlorophyll in the plant, leading to reduced greenness.

Figure 1. Fan leaves collected from Cherry Diesel plants the day before harvest. Flushing times depicted are (a) 14 days, (b) 10 days, (c) 7 days, and (d) 0 days.

RESULTS OF YIELD, THC, AND TERPENES

The flower weight, THC, and terpene content of the cured flower were determined for each flushing period. The data were analyzed statistically to determine whether the numerical differences in the data were due to the treatment. Overall, there were no significant differences between treatments for flower weight, THC, or terpene content (Figure 2a-c) (P < 0.05).

• Flower weight per plant averaged 97.3 g, and THC content averaged 21.9%.
• The dominant terpenes in the flower were beta-myrcene, beta-caryophyllene, and terpinolene, giving the flower an earthy and spicy smell (Figure 2c).
• Flushing times did not impact Cherry Diesel flower weight, THC, or terpenes.

Figure 2. Flower weight (a), THC (b), and terpene content (c) for Cherry Diesel flushed for 14, 10, 7, or 0 days before harvest. Significant differences are indicated at the 0.05 probability level.

MINERAL CONTENT OF CANNABIS FLOWER AT HARVEST

Flower samples taken the day before harvest were analyzed for the content of essential plant nutrients. Overall, there was no significant change in the flower’s mineral content due to different flushing treatments (Figure 3). In cannabis flushed for 14 days, nitrogen was 6.7% lower than in the zero-day flush treatment (Figure 3a).

Continuing to feed nitrogen can increase its concentration in the plant, reducing the need for the cannabis growing nutrients to use its reserves for essential functions. Phosphorus, potassium, calcium, magnesium, and sulfur were similar for all four flushing treatments (Figure 3a-b).

There were changes in iron concentrations due to flushing treatments. Iron was at least 50 ppm higher in flower flushed for 14 or 10 days (Figure 3c). Small changes were observed for zinc as well. Zinc was approximately 73 ppm higher in flower flushed for 14 days. The fluctuation in zinc did not follow a consistent pattern like iron. There was no significant change in manganese, boron, copper, or molybdenum (Figure 3c).

Cannabis cultivation nutrients like iron and zinc can accumulate in growing media over time. Feeding water during a flush may release some of these nutrients from the media into the plant. Additionally, zinc and iron are involved in the breakdown of chlorophyll occurring during senescence.

Data generated from plant parts, whether it be nutrient or THC concentrations, is naturally variable as only small samples of plants are consumed in the analysis. This may explain some of the variation seen in the data presented here. In other crops, ranges indicate whether leaf nutrient concentrations are deficient or sufficient for growth.

All nutrient concentrations detected in this study are within generally accepted leaf concentrations for the cannabis growing nutrients. Toward the end of the cannabis flowering cycle, the plant starts to naturally senescence. Plants nearing the end of their life cycle will uptake fewer nutrients as they remobilize from other plant parts. This may explain why little difference was observed in the mineral content of flower flushed at different times.

Figure 3. The mineral content of cannabis flower of plants flushed for 14, 10, 7, or 0 days. (a) Nitrogen, phosphorus, and potassium content of cannabis flower. (b) Calcium, magnesium, and sulfur content of cannabis flower. (c) Micronutrient content of cannabis flower.

EXTRACTION EFFICIENCY

Trim from Cherry Diesel was sent to an extractor to determine extraction yield and preferred characteristics of the wax.

• Cannabis flushed for 14 (17.97%) or ten days (18.21%) had the highest extraction yield compared to the seven (16.39%) or zero (16.17%) day flushes.
• However, the appearance of the wax for the zero-day flush was preferred over the other flush periods (Figure 4a-d). The zero-day flush was the clearest with the least amount of nucleation.

Although increased flush time in these cannabis plants resulted in higher extraction yields, the finished product was not as desirable for extraction.

Figure 4. Wax extracted from Cherry Diesel trim flushed for (a) 14 days, (b) 10 days, (c) 7 days, or (d) 0 days.

TASTE AND SMOKE CHARACTERISTICS OF CANNABIS FLOWER

Cured flower from Cherry Diesel was evaluated by a group of industry experts for flavor and smoking characteristics in a blind taste test. Overall, the duration of the flushing period had no impact on the flavor, smoothness of smoke, or color of ash (Figure 5a-d) (P < 0.05).

• The seven-day flush period had the highest “bad” rating (21.1%), and the 0-day flush had the highest “great” rating (16.7%).
• Most panelists rated the flavor of the samples as “okay” or “good.”
• The ten-day flush had the highest “okay” rating at 48.6%, and the 0-day flush had the highest “good” rating at 47.2% (Figure 4a).

A third-party laboratory tested the terpene profile, which indicated earthy to spicy flavors for all flush treatments.

• Most panelists rated the samples as either “earthy” or “sweet” (Figure 5b).
• 38.9% of panelists chose sweet as the predominant flavor for the ten- and seven-day treatments, and 32% selected sweet as the dominant flavor for the zero-day treatment.
• Panelists selected earthy most frequently (32.4%) as the dominant flavor for the 14-day flush.

Taste test panelists rated the ash color and smoke quality of each sample. Ash color was predominantly black or gray (Figure 5c).

• The smoothness of the smoke increased with decreasing flushing time, although was not significantly different (Figure 4d).
• Thirty-six percent of testers rated the smoke from the zero-day flush flower as smooth, whereas only 19.4% rated the 14-day flush flower as smooth.
• The 14-day flush had the highest percentage of harsh ratings (41.7%) compared to other samples.

Before testing, panelists were asked for their flavor preferences to determine whether personal preference would affect taste test results. Statistical analysis determined that personal preferences did not influence taste test outcomes (data not shown).

Figure 5. Results of a blind taste test of Cherry Diesel flower. (a) Ratings for overall taste of flower as bad, okay, good, and great. (b) Ratings for flavor profile of flower as earthy, sour, spicy, or sweet. (c) Color of ash after smoking the sample rated as white, gray, or black. (d) Smoothness of the smoke while smoking rated as smooth, medium, or harsh. Significant differences are indicated at the 0.05 probability level.

CONCLUSION

In a first-of-its-kind study, Rx Green Technologies evaluated the effects of a flushing period on yield, potency, terpenes, mineral content, and taste characteristics of cannabis flower. Overall, the length of the flushing period did not impact yield, potency, terpenes, or taste characteristics of cannabis flower.

Taste test results indicated a trend toward improved flavor and smoke quality with the zero-day flush. While there were no significant differences in cannabis nutrient content or cannabis supplements used, there was a trend toward increased iron and zinc in flower flushed for 14 days. This study’s results indicate no benefit to flushing Cannabis flower for improved taste or consumer experience.

SCHEDULE A PRODUCT TRIAL WITH RX GREEN TECHNOLOGIES

Want to try our premium commercial cannabis cultivation supplies and see the results for yourself? Contact an Rx Green Rep and schedule a product trial to try our top-quality, R&D-tested cannabis cultivation supplies in your grow.

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Bulk PK Booster Cannabis Research Study

Of all the elements and details required for successful commercial cannabis cultivation – there are two secret ingredients that are widely known for the crucial role they play.

Bulk PK Booster from Rx Green Technologies is a proprietary blend made up of the secret ingredients of potassium, phosphorus, and calcium.

This study revealed that Bulk PK provided superior nutrient contents to cannabis plants in comparison to the leading competitor’s cannabis nutrients, resulting in boosting the plant’s overall flower production and vigor.

In this Bulk PK Booster cannabis research study, we evaluated the effect of Bulk on two different cannabis cultivars. The statistics were outstandingly clear:

• Results showed plants that received Bulk PK treatment gained higher bud weight and yield per plant when harvested.
• No significant statistical differences were shown in THC or terpene content between the Bulk-treated flower and the Non-Bulk treated flower.

To view the full graph of data and results of our Bulk PK Booster plant application, read more about the research study below.

BULK IMPROVES FINAL FLOWER WEIGHT IN CANNABIS MATERIALS AND METHODS RESULTS AND DISCUSSION 

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