12 12 Cycle

The 12/12 cycle refers to a controlled photoperiod of 12 hours light and 12 hours darkness, commonly used in cannabis cultivation to trigger and maintain flowering. This light schedule mimics the natural shortening days of late summer and autumn, signaling reproductive maturity in photoperiod-dependent cultivars. The 12/12 cycle is distinct from vegetative photoperiods (typically 18/6 or 24/0) and represents the standard protocol for initiating flower development in indoor and controlled environments. Breeders and cultivators rely on precise 12/12 timing to evaluate strain characteristics, breeding stability, and phenotypic expression during the reproductive phase. Autoflowering varieties, by contrast, do not depend on photoperiod manipulation and will flower based on age rather than light schedule.

Breeders use controlled 12/12 cycles in breeding programs to standardize flowering timelines, observe floral morphology, and assess cannabinoid and terpene development across generations. Consistent photoperiod control enables reliable phenotype selection and outcross evaluation in line development.