Good Question! I've been wondering that myself (1st grow). I'm @ day 48 and all 6 plants are in flower with just a hint of the white hairs turning red. These were just misc bag seeds I had, so I'd say they're pretty average. I guess that probably means it's the # of days til flowering.when buying seeds online, it lists the flowering time. Is that the total time average before harvest? Or just the flowering time?, so u have to add in the veg time as well to get an idea of how long it will be?