Hello! I'm in Brooklyn, too. I've overwintered seedlings on my terrace by mulching and putting the pots up against the building, where they can get some warmth. On a fire escape, I think I would put the pot with the seedling in a bigger pot lined with newspaper, since the cold air would be coming from all sides and top/bottom. You could also use a milk jog "cloche" - cap off - over the top of the pot. I've had no problem with the low temps and overwintering seedlings. By the time the winter comes, your seedling should be a sturdy young plant.

Good luck!

PV

PV,

I just saw your comment all these months later -_- Thanks so much for your input.

I think i'm going to go with the milk jug idea that's really clever. I was also thinking about getting a foam cooler and mulching it, not sure which is more effective. Again, thank you very much for the peace of mind.