what hight do you begine flowring at?

mine are about 3.5-4.2 feet high. i figure let them get about five feet as i have about 9-10 feet high celling. at what high do you guys decide to switch to flowering?

plants will double, if not, TRIPLE in size during flower. i would put them into flower ASAP. it sounds like you'll be alright though (if you do it soon). it also depends on what strain or type (ie-sativa/indica)