Can't find the amswer any where REp if you can help

i live in NY near Niagara Falls, I normally grow indoors and this question would be simple t answer. I use the fox farm line and the open sesame is used a week before flowering to open the pours then used for the next three weeks then beastie buds and so on... So sept.26th is the day that it goes to 12 and 12 outdoors but i know from past experiences that plants are usually done around the harvest moon which is October 16 first frost starts soon after. Now do i start the open sesame back 67 days from that date (plants are 60 day flowering) or what that would be in five days and the hours of light a day are 14 of light and 10 dark. Does that seem right PLEASE HELP ME!!!!!!

Mine are just starting to flower now. MJ starts to flower when it determines the days are getting shorter. Nothing to do with 12/12 which is just a convenience for indoor growers.

you have to take in to account all the factors that go along with it not just the lighting stressing a plant can cause it to flower the temps could kill it honestly i think your over worrying about it 12 hrs is what a plant needs to stay in the vegative state IMO good luck tho great soil btw