The Flip: Triggering 12/12
The photoperiod trigger, why 12 h is safe but not sacred, and the light-leak myth put to rest.
7 min read
Short days start the clock
Cannabis is a short-day (long-night) plant. Flowering initiates when the dark period crosses a threshold — the critical daylength sits roughly at 12–14 h. The standard commercial trigger is a hard switch to 12 h light / 12 h dark, and flowering reliably initiates at 12 h across essentially all cultivars (Zhang et al., Plants 2023).
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