well hey there neighbor. im assuming this is your first grow? well when you grow outdoors, your children wont wait till 12/12 to flower. indoor growers just use that to induce flowering. as soon as the days start to get shorter, they will start to flower. this happens during june. so they will veg till then, then start to show signs of sex during june. they will flower for 2 months give or take. then harvest in august. good luck
Assuming this is your first grow also. They will flower round about late July/early August. Harvest late September/October. A bit later for sativas.
Yeah if you live in southern California you should start seeing lot's of preflowers real soon.(I have a plant preflower already) I usually harvest in late August to the begining of October but most hybrids in September. Depends on what you got under the sun and when you put it out there.