The relationship between light intensity, cannabis yields, and profitability

The purpose of this study was to analyze the relationship between light intensity, cannabis (Cannabis sativa L.) yields, and profitability. We also look for evidence that spectrum differences across broad‐spectrum horticulture lights and general‐purpose LEDs affect the relationship between yield and light intensity. Finally, we discuss the financial return of increasing light intensity in order to increase yields. We found that yields increase linearly with light intensity up to at least 1500 µmol m–2 s–1, which is at least twice the intensity that is most commonly used by cannabis growers. That relationship did not appear to be influenced by spectrum quality differences among the lamps included in the study. Finally, for all the intensity ranges that we considered, the value of the gain in yields from increasing light intensity far exceeded the cost of using more electricity.