Hello
When should I start indoor germination for an outdoor grow in USDA hardiness zone 7 (LI NY). I typically put warm weather vegetables outside on May 11 here. I will be growing Northern Lights photo period plants. I will be keeping them under a grow light until May 11 and with limited space I’m concerned about them becoming too large before they go outside.
Thanks
Welcome , whenever you put your tomato plants squash cucumbers things like that outside it will be safe to put cannabis outside. Watch the local farmers. I like to start the plants inside about 3 weeks ahead of going out. Good luck 
I know for my first outside garden girl same zone NY. I had my sprout in for the 5/15 planting party on here. She was over 10 in October. solo cup sprouts is what I planted similar size to this run
Here in MD it’s Mother’s Day for us. Frosts can pop up unexpectedly and the light hours are still short enough to flip you into flower which will then cause a reveg in early summer. You don’t want that.
So it comes down to how big you want them to be at harvest. I’m in Michigan and I don’t put anything outside till memorial day, just because of frost possibility. I usually start either clones or seedlings beginning of April and they become pretty large plants. And as @Fieldofdreams said about day light hours.
Not far off here in NB they go out around 10 - 14 days into May. Germ beginning of April.
Wow I thought you didn’t get ice out until June way up thar 
Thank you
except for the coast haha and valley weather is mild here.
the prairies now they got er rough
Start seeds mid to late May and move outside by early June. With this weather you might be able to start earlier.
