# Flip

> The flip is switching a photoperiod plant from long vegetative days to a flowering light schedule, usually around 12 hours of light, to start flowering.

- Canonical: https://genetixbay.com/knowledge/glossary/flip.html
- Also written: flipping, flip to flower, flipping to 12/12, switch to flower, flowering switch
- Glossary category: Cultivation and training · Evidence: Established
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

The flip is the moment a grower changes the light schedule from veg (typically [18/6](https://genetixbay.com/knowledge/glossary/18-6.md) or 24/0) to flower (typically [12/12](https://genetixbay.com/knowledge/glossary/12-12.md)) to trigger flowering in [photoperiod](https://genetixbay.com/knowledge/glossary/photoperiod.md) cannabis. The plant responds to the long, uninterrupted dark period, not to the light hours as such. Visible [pistils](https://genetixbay.com/knowledge/glossary/pistil.md) usually appear within one to two weeks, followed by the [stretch](https://genetixbay.com/knowledge/glossary/stretch.md).

## 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](https://genetixbay.com/knowledge/glossary/light-leak.md) can delay flowering or contribute to stress.

House position: flower doesn't have to be exactly 12/12. A [13/11](https://genetixbay.com/knowledge/glossary/13-11.md) 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.

## Related terms

[Veg time](https://genetixbay.com/knowledge/glossary/veg-time.md), [Stretch](https://genetixbay.com/knowledge/glossary/stretch.md), [Photoperiod](https://genetixbay.com/knowledge/glossary/photoperiod.md), [12/12](https://genetixbay.com/knowledge/glossary/12-12.md), [Re-veg](https://genetixbay.com/knowledge/glossary/re-veg.md)

## Read more

- [The cannabis life cycle, stage by stage](https://genetixbay.com/knowledge/basics/life-cycle.md)
- [Photoperiod and light leaks: 18/6, 12/12 and the dark period](https://genetixbay.com/knowledge/environment/photoperiod-light-leaks.md)