Take inside what you can. Cover the ones in ground with cloches or other containers or boxes. If not, cover with row cover or old sheets. Farmers usually use water mist or campfires to protect their crops. You can use these too. Good Luck!

A few degrees above frost, and you may be ok, but best to be sure. If they do get cold damaged, damage can vary from very little to death of the plant. There are too many variables from hardiness to the temperature and humidity of air and ground, wind etc. to say how much damage you will get. Best to take precautions.

Yeah, and don't forget that the weather people may decide about midnight that the night's low will be another 2-4 degrees lower than they told you before you went to bed. Which if you'd known, you'd have added another layer to your homemade cloches....

34 for southern Ohio......I've 34 plants outside in containers to carry to the garage......they've been out there in a stiff breeze and 55 degrees today. As soon as I can till they should be good to go. I still have 13 in the basement under lights a week behind the others. 47 plants of 17 diff varieties. I am eager to get started but I have been looking for blackberry plants today...now is the time...lol.

Someone on the radio today said that at the rate the seasons are accelerating this year, midwinter should be here in June!

You can put a cage over your young plants and cover it with an old comforter, blanket or tarp, then remove it after the forst warning has passed.

ljbrandt: How did you make out?

My pepper and tomato flats were getting too big for my lights, so I brought them upstairs to put outside in greenhouse during the warm weather. Got them out for several days, and they grew a lot. Last three days though, they've been stuck inside, no surprise, however waking up to a couple of inches of snow this morning was quite a surprise. Hope to see it warm up soon and get them back out in the green house.

I've always used plastic garbage bags down to about 25 deg. If it gets below that I'm SOL.