These guys have given you some sound advice. Not really much for me to add. But I would say, invest in a small microscope, or jewelers loupe, the outlay will be minimal, and it takes all the guess work out come harvest time. And as for 'cycle', there are so many variables that can effect a 'cycle'. The seed manufacturer will say 70 days, this is generally optimum conditions. Temperature, light, feed, introdution of bloom nutes at the right time all effect finish times. Use the finish times as a guide, not a set in stone timetable