OT?
I forgot a bag of groceries in my car's trunk a few days ago, with a head of lettuce. It got down to 32 or 30 degrees, probalby 30, for two nights before I remembered to get it, and the lettuce was fine, even the outer leaves.
I wish I'd paid more attention to how cold it was those nights, but if I'd thought about the lettuce, I would have gone outside and gotten it!