That’s a debatable subject. Some will say don’t defoliant at all.
Some will say 3rd week of flower, and do it all at once.
Personally, I start about a week into 12/12 and take a little at a time. At about 4 weeks, after the buds set, I’ll go in and cut off anything that isn’t going to get good light.
After that I leave them alone.
It’s also strain dependent fir me. When I’m growing a sativa, there’s no need. The open structure of the plant allows light in.
