Flower time will depend on strain, lights, nutes, and many other variables. Find a trichrome guide (I'm sure there's one somewhere on this board, I'm new here so I'm no too sure) and go buy a descent magnifing (spelling?) glass or a jewlers loupe and keep a close eye on your trichromes. When they start to turn a golden/amber color your gettin real close. But again, find a guide on trichromes, the best thing you can do is read, read, read.