Hey! If your autoflowering plants are at 3 weeks, they are most likely still in the vegetative stage or entering pre-flowering. Here are some tips:
1. Early defoliation (removal of large leaves):
It's not always advisable to do this too early with autoflowers, because they have a limited cycle and any stress can reduce the final yield. The large leaves (the “fan leaves”) help the plant store energy and perform photosynthesis. Removing them too early can slow down development.
2. Wait for flowering:
The general advice is to wait for the actual flowering to begin (usually around the 4th week for autos), and only then remove a few large leaves if they are clearly blocking light to the lower branches.
3. Soft techniques:
Rather than defoliating, consider low stress training (LST) if you want to improve light exposure without stressing the plant too much.
In summary:
Wait another week, see if flowering starts, and then maybe remove only some large leaves that cover the flowers or promising branches. Don't overdo it: less stress, more yield.