The 6-8 degrees is captured ground heat. You can reach the same goal using towels, sheets, cardboard boxes, or any other frost cloth. Just use them to good effect, i.e. cover plants as securely as possible all the way to the ground.

Frost cloth is supposed to be safe when in direct contact with plants as opposed to materials like sheets. I bought a bunch of the stuff a few years ago and 1) when the wind blows, it's useless, 2) when the temps drop into the teens for nights on end, it's useless and 3) when you don't anticipate a freeze and put the stuff over the plants, it's useless. I'd save my money.

So good post. I was just thinking I Ned's to get some frost cloth since it is now in the 80's. freezing days are coming very soon. My plants got burned last few years because I'm always too late in buying it. So what is the best or better frost cloth?

I like Arizona Bag Company.

Here is a link that might be useful: Az Bag Co

Thanks for the input. I ordered a small piece would see if it works

You're better off using towels and sheets (not as likely to blow away or become compromised), if the plants are small enough, though frost cloth is better for lightweight plants that can't tolerate much weight. Best protection of all for small plants is corrugated cardboard boxes, as long as rain is no concern. The corrugation provides excellent insulation and you're guaranteed maximum benefit from captured ground heat by a good, snug fit to the ground. You can get all you want for free from USPS.com.

Most large/larger plants are too difficult to effectively cover, IMHO. Just say no to large tender plants.

Almost anything works except plastic ... you just have to protect the tender leaves from the freezing air.

I bought some frost cloth because it comes in nice big pieces and I had a lot of chili plants to overwinter.

I make a tent thing out of saw-horses, 2x4s and king-size sheets and frost cloth ... weight the sides with bricks.

lay a string of outdoor mini christmas lights (incandescent, not LED) on the ground first and they provide just enough heat to keep things from freezing too badly.

My rule of thumb on frost cloth is half of whatever they claim. 4F would not be bad.

I've done some checking and measuring, and tend to get about 6F from plants covered snugly to the ground -- sheets, towels, boxes -- doesn't matter. Frost cloth, because it is so thin and light, is difficult to use toward the full advantage of a snug ground fit. More than once, I've awakened to find my efforts with frost cloth foiled by stiff winds, hence my general disdain for the material.

If I cover my plants with plastic, will N-Sulate in between protect them from getting burned by the plastic?

Yeah, but the problem with protecting with plastic isn't burning the leaves, it's that it doesn't provide much insulation by itself. If you're using plastic and something else under it, that'll work better, but keep in mind the total weight.

I just use sheets, sometimes double sheets. On very cold nights I put a heat source under the sheets. Some of my plants get a pvc and wire frame around them if I don't think the branches can handle holding up a sheet for very long (especially when it's wet).