Flowering Duration Photoperiod

Flowering Duration Photoperiod refers to the length of continuous darkness required to trigger and sustain flowering in photoperiodic cannabis cultivars. Most photoperiodic strains require 12 hours of uninterrupted darkness daily to enter and complete their reproductive cycle, though some lineages show variation in sensitivity and total flowering timeframe. This classification is distinct from autoflowering genetics, which flower based on plant age rather than light cycles. Understanding photoperiod requirements is essential for cultivation planning, as insufficient dark periods can delay or prevent flowering entirely. Breeders working in regulated indoor environments have historically selected for consistent, predictable photoperiod responses to standardize production timelines.

Breeders use photoperiod duration data to develop cultivars suited to specific growing environments—long-season genetics for outdoor cultivation in higher latitudes, and faster-finishing lines for commercial indoor production. Selection for photoperiod sensitivity also enables controlled breeding schedules and precise crop planning.