Short Day Plant

Short day plants are cannabis varieties that initiate flowering when exposed to periods of uninterrupted darkness exceeding a critical threshold, typically around 12 hours or more. This photoperiod sensitivity is a core breeding trait affecting cultivation timing and seasonal growing cycles. Short day plants contrast with day-neutral or autoflowering genetics, which flower based on age rather than light cycles. Understanding photoperiod requirements is fundamental to cannabis breeding programs, as it determines whether a strain suits indoor controlled environments, outdoor seasonal growing, or hybrid approaches. Most traditional photoperiod-dependent cannabis landraces developed flowering responses tied to equatorial or temperate seasonal patterns.

Breeders selecting for photoperiod-dependent traits use short day genetics to develop strains requiring specific light schedules, enabling precise crop timing in controlled environments. This trait remains central to many breeding programs targeting specific harvest windows or regional growing seasons.