I don't think this will be quite as simple as you make it to be. You have kinda the right idea, it is possible to force flower outdoors, but if you are covering with plastic trash bags you have to keep a look out for mold. As for the light/dark period, 12/12 is really an indoor thing, since (in the norther hemisphere at least)you don't get 12/12 outdoors till late october/november(when its usually way too cold), you would probably be better off putting your bags on an hour or 2 before the sun sets EVERY day until the actual day light is to about 13 hours of light(near end of september) and then you wouldn't need the bags.
bonedaddy420 Reviewed by bonedaddy420 on . help flowering my ganja pls i live in the okanagan where it getts realy hot and dry in the summer and very cold and dry in the winter and it getts too cold very fast hear when its time for winter and vise versa. i cant let them mature naturally because by the time the sun lets them mature it wouldnt give them sufficient enouf time to ripen before the cold snap comes. so i have 8 plants that range between 2 feet and 4 feet and i have to make them flower now so they have the rest of the summer to ripen. i am going to Rating: 5