Depends on where you live.
Most areas, including most of the United States are on 12/12 now (I live in the Great Lakes region, and it started here a few weeks ago). Harvest time is later the further north you go. Go to theweatherchannel.com and look at the sunrise and sunset times. If the time between sunset and sunrise is twelve hours or more, your plants will enter the flowering stage if you put them outside and away from artificial lights.
Happy growing.
~Ethno