You can make it bud whenever you want, just set your lights to 12 hours on 12 hours off, also the time it will take depends on the strain of seed you have. I would let it bud untill the hairs start to turn brown while allowing some to remain white that way you get the most THC out of it. About 2 months is the average but it all depends on your setup , lights, ventillation , fertillizer etc. Anyway good luck and good smoking