In late 2018, the Planet-3 team managed and grew hemp in an indoor closed-loop system in order for research and development purposes into growing nutrients and soil substrate. The purpose of the test was to:
- See if the cultivation of cannabis in hemp fiber was an alternative to coconut fiber.
- To see the difference in cannabis cultivation in retted hemp fiber and unretted hemp fiber and
- Compare Canna’s A and B NPK nutrient to our experimental hemp-derived NPK. The total program was 3 months long and involved daily qualitative data gathering on everything from environmental controls like lux, humidity, temp, barometric pressure, Air CFM and velocity over the growing unit.
CATEGORY: Product Formulation, Equipment Sourcing
SKILLS: Biochemistry, Cultivation Science, Horticultural Engineering, Nutrient formulation, Plant Biology
PROJECT LEAD: Taylor Ange
We recorded data for the plants including daily mass before watering, hight, pH, EC, number of leaves, soil temp, leaf temp. The pH of the water with the nutrients was also taken and recorded every time before watering began. The veg and then flower grow chamber was a 10-ft x 10-ft custom made hard wall sealed chamber with independent HVAC pushing a constant 520 CFM of air over our plants at 3-miles per hour both over our canopy and our base. For lighting, we used 2 BIOS Icarus Gi 660-w adjusted for 20 in over canopy height in veg. We measured PPM (Truncheon) daily. We had a par measurement of 228-par for the seedlings then adjusted the lights to 490-par in our veg and 640-par in our flower. Light scheduling was 18/6-hr from germination through vegetative, then was 12/12-hr through flower. We maintained a humidity level at 65% during our seedling phase and lowered it to 45% with the use of a dehumidifier during our veg and flower stage. For temperature values, we maintained 21 degrees Celsius until flowering stage when we lowered the temperature 4 degrees to 17 C. We had a constant barometric pressure of 25-in to 32-in. All water was obtained by use of a DI system hooked up to city water. The plants were all germinated from certified Katani hemp seeds sourced from a Canadian supplier. All technicians wore lab coats and both facial and hand and foot sterilized PPE. All ancillary equipment was sterilized each day.
Our variables were our tests which included three germination tests using coconut fiber germ pods, the paper towel method, and unprocessed hemp bast fiber. Due to the paper towel method physical manipulation of the germinated seedling was needed to transplant and this could have led to mixed results in final data. During the vegetative stage, we used three different types of soil substrate, CANNA coco coir, retted hemp fiber and unretted hemp fiber all with a 30% perlite mix ratio. We also tested two different NPK nutrient blends Canna Coco A and B and our own proprietary hemp-based NPK using fermented hemp along with Canna’s Rhizotonic and Canna boost into later veg stage and PK on week one of flower. Mechanical failures were there was a breakdown of our HVAC system during day 15. Human error was three plants were not watered on day 6 and a light was left on for 24 hours on Day 20.
We conducted multiple tests on the plants starting with testing seed germination. There were three different methods used each method with 40 seeds each for a total of 120 seedlings. Two methods were controls including germination using dampened paper towels, and germination from germ pods constructed from coconut fiber. The third germination test we used hemp bast fiber formed into germination pods similar to those made from coconut fiber that had not been processed any further than just processing out all of the hemp herd. All seeds were “cracked” by soaking for 12 hours in a tub of DI water.
After the first three days when all seeds had just popped, we transplanted the popped seeds from the paper towels to 9-cm diameter pots with Canna coco coir. On Day 7, the rest of the seeds that germinated in the coconut fiber pods and hemp pods were transplanted to 1-liter pots. Out of our three test groups for germination each group was divided in half making 6 test groups half of the groups for each germination process was given and Canna A and B were started on day 7 along with the other half being given P3’s A and B Hemp nutrient also added to both tests was Canna Rhizotonic. The dilution ratio for both Canna A and B and P3 A and B was 1/250. The dilution ratio for Canna Rhizotonic was 1/320 with DI water. All watering was measured and done by hand for accuracy. Water was applied directly around the base of the plant a ½ and in from the stem in a circular manner.
This is the full feeding schedule for P3’s experimental nutrient line. Dilution ratios along with the amount of water each plant was given were consistent for each test group but the amount of water with dissolved nutrients changed daily based on the look, weight, and water retention of the plants and soil. Daily weight measurements were taken to determine soil water absorption. All coco coir was first washed then autoclaved before being used in the grow to remove salt and pathogens. Plants were transplanted at around Week 3 to 10-L soft wall pots and then on Week 5 to 20-L soft wall pots. Scag netting was used to support the plants over the duration of the test and bottom leaves and stems were pruned to keep efficiency. No pesticides were used.
Starting in Week 7 Canna PK was used after first signs of flowers and was continued for 2.5 weeks on both nutrient tests. Light at this point was dropped to 12/12-h and all plants that were getting close to outgrowing their pots were transferred to 20-L soft walled pots. All nutrients stopped for canna nutrient plants at Week 9 and Week 10 for experimental nutrients. Final plants were weighted and the test was concluded at Week 11 for Canna nutrients plants and Week 13 for experimental nutrient plants.
Germination: Seeds germinated using the paper towel method experienced a 46% mortality rate from germination to planting. Those in coconut fiber experienced a 31% mortality rate and those in hemp fiber experienced a 52% mortality rate. Both the coconut and hemp fiber germinated seeds were, on average, bigger than the paper towel germinated seeds with a ~6-in height difference and a ~4-in^3 difference in canopy area over the total test. The unretted hemp fiber germination pods had a pH of 7.8 most likely due to high protein density. This is what we hypothesize is the cause of the higher mortality rate of the hemp germinated in unretted hemp fiber than its closest alternative, coconut fiber. The paper towel method results might have been a result of the physical manipulation of the seedlings during transplant.
Vegetative/Flowering: For the seedlings who made it through the germination phase, the mortality rate for coco coir was 8%, retted hemp fiber was 10% and unretted hemp fiber was 41%. Both the retted hemp fiber and the coco coir performed nearly identical with pH reading around 6.3 to 6.8. The unretted hemp coir had a standing pH of around 8.5 most likely leading to the drastically high mortality rate. Also, the plants that were grown in the unretted hemp fiber were on average 50% smaller and had stunted leaves and flowers. The Canna nutrient and the experimental nutrient qualitatively produced similar growth results. However, when the mass of the plants was finally measured at Week 13 by digging up the entire plant and removing all dirt and debris and then placed on a scale, the total mass of the plants grown with experimental nutrients was 18% less than the total mass of the plants grown with Canna. Additionally, flowers did not appear on the plants grown with the experimental nutrients until a week after the Canna nutrient-fed plants flowers appeared.
Summary: The plants germinated in coconut fiber had a higher success rate both in the rate of growth and mortality but if the hemp fiber used in the other germination test was retted, the test might have been more effective at plant growth than what it was. The high pH in the hemp lead to a large final mortality rate in both plants germinated and grown in unretted hemp fiber as opposed to the generally similar mortality rate experienced with those grown in retted hemp fiber and coco coir. The hemp-based nutrient for the NPK formulation behaved surprisingly similar to those of Canna’s A and B NPK nutrient line. The strongest and healthiest plants resulted from the hemp grown in coco coir and using the experimental NPK nutrient.