Don't bring them in. They can handle 40-degree nights OK.

Basil is quite frost tender, though, so if they predict a frost (32 F) I would bring it in.

Basil is frost tender, but the plastic container will give an extra degree or two of protection, so if you have an old sheet or lightweight blanket you could drape over the containers, it might be easier than bringing them inside, and still give you peace of mind.

This whole sheets/tarp thing isn't clear to me. It seems to me that, even if I cover containers or plants with a tarp at night during cold freezes, the container should still fall to the same temperature as the out-of-doors. The tarps are not sealed or heated from within, and have little insulation value on their own. How can just laying a tarp down keep a jug/plant from getting as cold as the outer air? I know frost comes when moisture from the air falls as it cools, crystalizing to ice wherever it rests. It makes me wonder if the cold temperatures are OK, but the ice crystals are not, like having a frost-tender plant reach 28 degrees without frost settling on it is OK, but having it reach 28 degrees and get covered in frost will kill it?

What am I missing here?

Deanna, I'm with you... I have no idea how a sheet can help.. it's not like covering up in bed with your body generating heat to help warm you up... I will cover my hosta in the spring, but as you said, that's to keep the frost crystals off the plant... But... when it gets too cold, the hosta will freeze whether or not they are covered..I think then you've got to worry about the plant's internal structure freezing.

I only have about 8 jugs this year.... it's easy for me to put them in the garage if it gets too cold..

I'm skeptical about the covering thing, too, although I read it all the time. I'm thinking that if the containers are on the ground that covering them might help retain the heat that the ground absorbed during the day. I can't imagine that it'd help much if the containers are elevated on a table or something. Of course, what do I know? LOL.

Usually the temps drop through the night and the morning damp air freezes as a layer of frost right around sunrise. It is the formation of the frost on the foliage of tender plants that does the main damage, often killing tender annuals.

Covering the plants give a little layer of protection and frost forms on the covering, not the foliage. That makes a huge difference this time of year.

You could shove them in the garage overnight. That protects because the outside air usually only drops to it's coldest point for a few hours. The air in the garage won't change temperature as quickly and that keeps the plants in conditions where frost can't form.

Lynda

As far as I know it's the frost on the leaves that does the damage. Last fall I was at the local amish farmer's little produce store and mentioned that my peppers were still producing like crazy. He told me they like the cool weather but that we were getting a frost the next night and suggested I cover them with a sheet or something. I think the idea is to keep the frost off the leaves.