We've used concrete blankets a few times for soil warming. We've also used a trampoline cover for a sunshade.

You need to ask if it's has a uv protection or not. Without it will not hold up long.

From what I have seen, Marla, they all have UV and are rated from 6 to 16 years, apparently based on the MIL thickness..but could be product chemistry too. I wonder if the blue tinted ones pass enough light and all the proper wavelengths for plants....

I'll take a look at concrete blankets ....I don't think they are used out here.

Blue light encourages vegetative growth over floral growth. So I think you may find the blue-tinted ones very useful in suppressing or delaying bolting in leaf vegetable crops in the spring, as well as for growing any kind of leaf crops in the fall. Just my two cents.

Concrete blankets might be called something else. Check with concrete finishing companies if they have some old ones. You might be able to get any, we have ours because hubby used to finish concrete in years gone by.

Marla