I count bud set as day 1, usually 10-14 days after flip to 12/12
Here's from the web in support of my position:
When Does the Flowering Stage Actually Begin in Cannabis?
The
start of the flowering stage can be a bit subjective, depending on how you define it. There are two common ways growers mark the beginning of flowering:
1. Transition Period (Pre-Flowering) – Week 1 of 12/12 (Not Official Flowering Yet)
- When you switch to 12/12 lighting (for photoperiod plants), the plant does not immediately start flowering. Instead, it undergoes a transition phase, often lasting 7-14 days, where it stretches significantly and prepares to bloom.
- Some growers call this period "Week 1 of Flowering", but the plant is not yet forming real buds—just showing early signs.
2. The True Start of Flowering (Bud-Set) – Usually After 10-14 Days of 12/12
- Many experienced growers consider flowering to officially begin when bud sites form, usually around Day 10-14 after the 12/12 flip.
- This is when:
- White pistils (hairs) appear in clusters at the nodes.
- The plant stops stretching as much.
- The first signs of trichome development begin.
This means that if a strain has an
8-week flowering time, you should start counting from
the first sign of actual flower formation, not from the first day of 12/12.
For Autoflowers
- Autos begin flowering on their own, usually between weeks 3-5 from germination.
- The start of flowering is marked not by time but by visible pistils forming at the nodes.