Short Day Plants

Short day plants are cannabis cultivars that initiate flowering when exposed to approximately 12 hours or fewer of light per 24-hour cycle. This photoperiod sensitivity is a fundamental trait in cannabis breeding, reflecting the plant's natural adaptation to seasonal changes in its native regions. Short day varieties typically include photoperiodic (non-autoflowering) strains that require manual light cycle adjustment in indoor cultivation or natural seasonal light reduction outdoors. Breeders working with short day genetics often select for stable flowering triggers and predictable maturation timelines. Understanding photoperiod requirements is essential for cultivation planning and for developing stable breeding stock. This classification distinguishes from long day photoperiods and autonomous (autoflowering) genetics that flower independent of light duration.

Breeders leverage short day plant genetics to create photoperiodic cultivars with controlled flowering windows, enabling precise indoor scheduling and outdoor seasonal cultivation. Short day genetics remain foundational in traditional breeding programs for trait stability and backcrossing applications.