Two Phases of Cannabis Growth

Cannabis grows in two phases. During the vegetative phase you light plants for 18 to 24 hours to inhibit flowering and put on vegetative growth.

If you don’t have a lot of space and cannot accommodate large plants, you’ll veg your plants for three to four weeks, then shift them to a flowering phase with alternating 12-hour cycles of light and dark (or the specific critical daylength required by your strain) to induce flowering.