Cannabis Grow Trial Sees Water, Nutrient Savings
With a commercial cannabis operation, variable overhead costs can quickly eat into profits. A recent trial looked at the advantages of HydraMax recirculating deep water culture (RDWC) systems from Hydra Unlimited. In the trial, a 7,000-plant operation saw a significant reduction in water and nutrient consumption when using the HydraMax solution, compared to the grower’s standard coco coir substrate technique. The investment in expensive, time-consuming water content monitoring was also eliminated because the HydraMax buckets are always full.
The trial with a five-year-old company involved four 20-bucket HydraMax arrays grown indoors without ambient sunlight. The system was monitored throughout the test period for nutrient/water, temperature, oxidation-reduction potential (ORP), electrical conductivity (EC), pH and dissolved oxygen by Nuravine monitoring equipment. Room atmospherics were continually checked for light intensity, dew point, relative humidity and vapor pressure deficit. An Athena Ag Blended nutrient line was chosen for the trial with a standard feeding and irrigation (fertigation) schedule set in place.
A typical substrate/fertigation operation utilizes 12 substrate cubes beneath a 4-by-4 foot LED light and uses 1,310 gallons of water per light. This comes to the 12 plants consuming 1.3 gallons per plant per day for 12 weeks, including plant evapotranspiration and fertigation run-off. A trellised table system running water content thresholding with nine coco coir substrate bags beneath the same lighting will use 453 gal. of water per light.
With the Hydra Unlimited RDWC trellised table setup, four HydraMax buckets with TetraBase hydroponic media beneath a 4-by-4 foot LED light consume 235 gallons of water per light. This typically provides a 50% to 80% improvement in water conservation depending upon the substrate cultivation technique that Hydra Unlimited replaces.
Under the trial’s 320 square-foot lighted canopy, the 80 plants utilized 0.7 gallons of water per plant per day and consumed a total of 4,704 gallons over the 12-week grow period. This represents a 76% reduction in water consumption over the operation’s standard substrate methodology and generated a total cultivation cost (nutrients and water) of $14.25 per plant.
“We were pleased by the results of the trial,” said Hank Bonnah, Hydra Unlimited principal engineer and chief scientist. “Less water used meant reduced nutrient waste. By targeting the crop’s fertigation consumption, the HydraMax solution dramatically dropped the per-light cost of cultivation.” A video is available at www.bit.ly/HU-HydraMax.