Cannabis plants flowering with photoperiod Commercial cannabis growers should quantify the specific inductive photoperiods required to initiate flowering in the cultivars being grown at their facilities.
Photo by Stewart Maxwell
By Stewart Maxwell| April 8, 2021
Most commercial cannabis cultivars are obligate short-day plants. This means that they have evolved the ability to synchronize their physiological flowering response to seasonal changes in day-length to optimize reproductive success.
Photoperiodic flowering responses in these cultivars are regulated by the length of the skotoperiod or dark period. When the skotoperiod exceeds a critical threshold (about 10 hours for most), flowering is initiated. The photoperiod duration required to initiate flowering for a specific cultivar is referred to as the Inductive Photoperiod (IP).
Cannabis growers typically influence flower initiation through use of supplemental lighting and blackout curtains to control photoperiod. The photoperiod is usually set at 18/6 (light hours/dark hours) for vegetative growth and moved to 12/12 for flower initiation when plants reach an appropriate developmental stage. While this approach remains valid for indoor cultivation, for commercial greenhouse operators, a more dynamic approach to photoperiod control can increase profits and efficiencies….
