Through decoupled aquaponics, commercial farms can produce high-quality fish and high-value crops in a controlled environment. They are successful because they can manage the fish and plant components separately. The use of aquaponics has also been a growing trend within the Cannabis industry. When the value of the harvested flower is largely determined by the concentrations of cannabinoids and other secondary metabolites such as terpenes, it makes sense to focus on creating growing conditions that maximize these compounds. However, there has been little focus on the management of nutrients in aquaponics systems for optimizing plant production.
A previous experiment showed that cannabis plants grown with aquaponics had higher cannabinoid and terpene levels than when grown with hydroponics, despite being smaller in stature and yield. While the lower yield is not ideal, the higher value of the harvested flower offsets this shortcoming. Therefore, in subsequent experiments we decided to look at decoupled aquaponics cannabis production with single-pass nutrient flow, as well as various recirculating flow treatments.
In the first experiment, cannabis plants with single-pass flow demonstrated the highest cannabinoid levels and most diverse profile of secondary metabolites compared to recirculating treatments and a hydroponic treatment. The second experiment built off the first and added a hydroponic treatment with 10% aquaponics effluent and a more actively managed recirculating treatment. In addition, supplemental lighting was actively managed to increase plant growth during low light conditions. Results show that aquaponics is not only a viable method for growing cannabis, but perhaps a better method for growing hemp flower with more diverse cannabinoid and terpene profiles and thus potentially higher medicinal value.