Hi HarrysOG, Yes i agree to your 4 Weeks, but I wont fix it on a Number. It depends In the Plant how nice she grows. I would wait until she is min. 40 cm tall and you stopped training( topping , fimming) to have a nice Canopy. So the Plant is well prepared to the Flowering time , where she uses to stretch to nearly double size ( depends in strain). Happy Growing