It freezes. Don't know about covering it. Pick some, cover some.
Tally HO!

I cover it if it goes into the 20's and it seems to do fine. I grow it in containers on the deck and have taken them in a few times when we went into the teens last year but otherwise they stay outside. I've been to 29 this year already and didn't cover and they did fine.
Happy Growing David

Thanks David!
Tally HO!

Some of mine got bit the other night when we had that light freeze. I covered mine tonight and will leave it all covered 'til Saturday. I think it depends on what type ~ seems like the thicker-leaved varieties sailed through the freeze with no damage at all, but the thinner leaved types were damaged a little on the tallest edges.

Depends on the type. Some lettuce can take the cold but not the frost, or so I have been told. So I cover mine till I know more about it. I have had some go through the whole winter but I have had some get bit on the first frost. So di we leave you just as confused as you were before having the qquestioned answered.

Thanks for all of the info. I watered everything in real well and covered the lettuce with sheets. There were a few places that got a little nipped but all in all everything turned out OK and we got down to aroune 23F.