When I flip the lights to 12/12, the NEXT day is 1. In other words, the next day is the first complete day of 12/12. Then I mark the growroom calender at 7, 14, etc... Usually around day 50 I start to check the trichomes, and depending on the strain and success of the grow, some can be harvested and others need a few more days .. or weeks.
jv