It might not hurt to cover them at night.But I think it's going to get colder in the next few days.Good luck Jim

I would cover them.

You could do damage covering them with plastic if they get hit by the sun. It's better to cover with old sheets or something of the kind, or what I do is use 'frost blankets.' Then they won't overheat in the sun like plastic, and they actually keep in the warmth better than plastic does too. I'm really sold on the frost blankets--been using them for I guess four or five years, and they put up with all sorts of abuse, and let the rain in so I don't have to worry about that, and things do at least as well under them as they do in the greenhouse, where they don't always get watered when they should. There are several different weights of frost blankets--if I heard right a local garden center was touting some that protect down to twenty degrees. Most of mine are supposed to protect to 24. They are apparently cozy enough that they have attracted some stray cats that help keep the local rat population under control--kinda squashed some plants, but they'll be fine in the spring. Looks like we are going to get an unusual amount of cold the next few weeks. May I say, and please excuse me while I shout, I HATE COLD WEATHER!!!