Athosanswered grow question 6 years ago The first thing that you need to consider when defoliating is that every time you do it, you will delay the development of the plant a week. Second, the idea behind defoliating is to expose lower leaves that are feeding lower shoots, and to avoid wet leaves due a too packed foliage.
That been said, it is recommended that the first time is done around day 21 since breaking soil and then 2 weeks later, letting it recover 1 week and then switch to 12/12. The idea is to pluck those fat fan leaves so the light reaches some of the lower leaves that are feeding lower shoots. The lower leaves will eventually dry up naturally as the newer foliage shades them, you can pluck them now or later it will not matter much either way; I prefer to leave them, they function as an early warning against deficiencies. After switching it is ill adviced to defoliate during the preflower phase, wait until day 21 and then let the plant recover and make bud sites, you can defoliate one final time at day 45. Also You might want to leave 1 plant with no defoliation just to see if it really helps or not yield wise. Some LST to open up the plant really helps and so is TOPing or FIMing.