Flush time ?

i'm not a fan of either of those options. Nor, do i recommend long periods of darkness for any plant. (*sorry, this paragraph relates to photoperiods, see '*' below) The stress of extra light the last week or so should not cause any major problems, if you want to try it. Any extended period where the plant does not get the necessary minium uninterrupted darkness in order to maintain hormonal balance of bloom.... playing with fire, but it takes a long time for a hermie to develop and a long time to see Re-vege leaves and such... so, as long as you avoid that, shouldn't be much harm. again, i don't suggest doing that... there's no way a few 24hour light cycles at end will cause any major difference in yield that is worth the effort and risk. Flush.. meh.. in a substate like coco initial studies have shown the exact opposite of what people profess so confidently... it can actually increase mineral content in the buds due to CEC of coco... it'll leech out things as you flush it in improper ratios/conccentrations. In the other mediums, absoutely no increase i mineral content. It is also a myth that the plant needs no N in flower... It needs a proper balance at all times. If that shifts at certain points, that's beyond my knoweldge. Fertile soils around the world don't just magically change during a flower's bloom, i'd say they have evolved to handle it just fine. *my bad, these are autoflowers? can ignore bits related to photoperiods above... 24 hours -- only if not providing max DLI. if you provide max DLI at 18hours per day, stick to 18 hours per day. I'll leave the rest for anyone else reading with photoperiods.