The flip is the moment a grower changes the light schedule from veg (typically 18/6 or 24/0) to flower (typically 12/12) to trigger flowering in photoperiod cannabis. The plant responds to the long, uninterrupted dark period, not to the light hours as such. Visible pistils usually appear within one to two weeks, followed by the stretch.
In practice
Growers flip once the plant has filled about half to two-thirds of the space it should occupy at harvest, allowing for the stretch. The dark period must be truly dark; light leaks can delay flowering or contribute to stress.
House position: flower doesn't have to be exactly 12/12. A 13/11 schedule is endorsed, and some cultivars flower with 14-15 h of light. In practice that means around 12 h at high intensity, with sunrise and sunset ramps adding the rest. Test your cultivar.
Don't confuse with
- Autoflowering: flowers by age, so there is no flip.
- Flip (slang, selling): unrelated.
18/6 is the standard vegetative light schedule: 18 hours of light and 6 hours of darkness each day, keeping photoperiod cannabis from flowering.12/12 is the classic flowering schedule for photoperiod cannabis: 12 hours of light and 12 hours of uninterrupted darkness, which triggers and sustains flowering.The daily length of light versus dark; photoperiod cannabis flowers when nights grow long enough, rather than at a fixed age.The female reproductive organ of a flower (ovary, style and stigmas); in cannabis growers loosely call the visible white stigmas "pistils".The stretch is the rapid increase in height in the first two to three weeks after switching to flower, when many cultivars grow 1.5 to 3 times taller.A light leak is unwanted light entering the grow space during the dark period; in flower it can delay or disrupt flowering in photoperiod cannabis.13/11 is a flowering schedule of 13 hours light and 11 hours dark; GenetixBay endorses it, as most cultivars still flower while gaining extra daily light.A day-neutral cannabis plant that starts flowering by age, usually a few weeks after germination, regardless of light schedule; the trait is mainly recessive.Veg time is how long a photoperiod plant is kept in vegetative growth under long days before being flipped to flower, which largely sets its final size.Re-veg is returning a flowering or harvested plant to vegetative growth by putting it back under long days, often to save a genotype after harvest.
