My plan at the moment is to veg a bunch of sativas for the next few weeks then put them on 12/12 for 4-6 weeks before putting them outdoors in an unheated greenhouse.
I’m in Southern NY. I have done this out out of necessity for space in the past and remember being extremely happy.
April 1st is 9 weeks away. There are 12 hours and 41 minutes of daylight with an average low temperature around 37°F (3°C). While not optimal I know that mature cannabis will not die if its not freezing.
Besides the cold i have the increasing sunlight to worry about. About a min a day. Some of these sativas need 14 weeks. I am just trying to figure out when i should sow ( seems about now)
Curious to hear from people who have done similar things in the past and when would one have to worry about them entering back into veg.
From what I gather if i pollinate the plants the seeds will finish up regardless of if the plant goes bank into veg.
I think you’re better off starting them on 12/12 indoors to sex them cull the males, revegg the females…then put them in the greenhouse in the summer months…around October/November add some kind of heating in the greenhouse and let them finish during winter months…that’s what a buddy of mine is doing and he’s in Michigan…
I think your plan will work but you may need to use a “black-out” covering to keep them in flowering mode.
-edit- After reading your post again , I think I misunderstood it. Please disregard previous message 🫣
i think you misunderstood me philcuisine im taking about harvesting about 15 weeks from now.
I know what im saying works. I have done it.Its been a few years and dont remeber how long i have into spring before plants will start to re veg.
a black out cloth would surly work and might be used if they dont finish by the time there is too much sunlight. But when is that ?
@PsillyRabbit , Buy a farmers almanac that shows the hours of daylight each day. I would expect anything less than 11- 10 hours of darkness will cause them to stop flowering. 
Depends where you are, and the variety you’re growing. Safe bet would be to determine when your area is at 12 hours of daylight. That would be a very rough estimate of when you should aim to have them finishing.
You’re overthinking way too much then…do what @Magu said farmers almanac are cheap and very useful for all types of growing outdoors…problem solved.
Plenty of Online Charts showing Daylight Hours by Day, Month, and Location. A few notable Sites: timeanddate.com sunrise-sunset.org and aa.usno.navy.mil ALL should provide the information you seed. SS/BW…mister 
what am i over thinking?
I have looked at these charts. I have already determined when in my area there is 12 hours of sunlight. Thats way I provided that info in the op.Jus because a plant gets 12 hours and 1 min of light doesn’t make it re veg…sorry if i offended you all or if you think i want to be spoon fed.
“Depends where you are, and the variety you’re growing.” is the real response. and that is where i was hoping conversation would come into play.
I think anything more than 14-16hrs. of light will make your plant start revegging…I also think it all depends how long your plants have been in flower, the longer it’s been flowering the longer the reveg time will be…hope this helps.
Hey @PsillyRabbit I’m actually doing the same thing and I think your thought process makes sense. My plan was to have plants finish outside in the greenhouse by mid to late April as I’ve noticed plants starting to reveg around the beginning of May (~13 1/2 hours daylight).
However, I started my seedlings in December and early Jan to give them a few weeks of veg then I started flowering some of the longer stativas (14+ weeks) already in order to finish by late April. If you started some of the 14 week plants now on 12/12 from seed they might just squeak by finishing by the first week of May. Ideally though these should have been started several weeks ago imo.
Yes this has been my experience.
I apologize for volunteering info that I “thought” was solicited. I assure you, it won’t happen again!! SS/BW…mister 
can we still bee friends 
Sounds like aiming for harvest beginning of may would be ideal.Later might be pushing shade cloths.
This is an experiment ive been meaning to try, but not with long season sativas. Just the idea of harvest at the end of april gets me alll juiced up 
Ill be lurking to see your progress
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