With the return of Cannabis spp. to legal status in a growing number of states, excessive use of energy for indoor Cannabis cultivation is quickly becoming a threat to several large urban power grids. Most of this energy requirement can be traced directly to the High Intensity Discharge (HID) lights used as the primary source of light for growth of Cannabis plants. HID lamps output a broad spectrum of light including the entire Photosynthetically Active Radiation (PAR) action spectra. While effective as the only source of light for indoor plant growth, HID lamps generate a great deal of heat and emit light outside the PAR action spectrum that may not be used by the plants. Our experimental results show that LED technology has come of age for horticultural applications, and that in addition to being the best choice for lower energy consumption, LumiGrow LED arrays are superior to HID lamps for several aspects of plant development. The yield of dried Cannabis flowers is comparable for the LumiGrow 650W LED array and a 1000W HID lamp covering the same space, allowing for a savings of almost 50% on electrical consumption. LumiGrow LED arrays also generate less heat, allowing for an overall energy savings of up to 70% for the grower. This decrease in electrical use may eliminate the current problem facing electrical grids.
This study also reports LumiGrow LED arrays impart is an average increase of 5% in the total THCA content of dried Cannabis flowers compared to plants grown under HPS lamps. This increase in THCA % production by plants under our LED arrays has allowed growers and vendors to compete effectively in their local markets by providing the highest quality Cannabis to the public. Another advantage imparted by LumiGrow LED arrays is the ability to adjust the relative ratio of blue to red light, often referred to as “Spectral Tuning”. These adjustments provide users the possibility of eliminating some common PGRs from their growth programs. This includes rooting without the rooting hormone IBA, and producing compact plants during flowering without the use of Daminozide or other similar PGRs. These facts alone are of great import and will likely lead to a wholesale paradigm shift away from HID lamps and towards LED lighting for indoor horticulture.