iv about 2 week old seedlings id say theyl start veg in a week or 2 stil only two sets of leaves best off letting them veg for a month or 2 regardless of preflowers let the plant grow a bit then when its around 3 or 4 foot and a nice few leaves change photoperiod to 12/12 make sure there preflowering first you have to wait until that happens for the plant to flower