Whens the absolute earliest you can plant outdoors?

simple question.. i live in southern california, and it doesnt get very cold during the winter, i was wondering if i could plant now in september, and then grow it october novemeber december jan feb march april, and then may or june it should be completely finished and i can begin another grow, so i'd be working with 2 a year

if it's hot all year round heat wont be a problem but will you have enough daylight hours i was wondering?

it'll probably be something like 10/14