I had the same concern about SWC too. I replaced my black plastic mulch for a white one. I noticed a cooler temp difference. I also think as the season moves on you plants will get bigger and shade a good part of the SWC's. I have my SWC's against a south wall of my house so they get a little more protection from the heat that way too. Just my 2 cents, good luck.

I agree...use white plastic instead of black. You can also shade the sides of the SWC like this

{{gwi:1315300}}
taken last year

I had the same concern and swapped over to white plastic cover in March. The temps in March with black plastic cover were over 80 so I changed out to white plastic. I'm in Z7b also. White plastic helps. In June when the sun starts getting really intense here, I am going to pay close attention and shade the sides of the containers if necessary. Thanks for posting pictures Atascosa.

You are more than welcome.
The material I used is RMAX insulating sheets. You can find it in your local home improvement store and comes in 4'x8' sheets. One sheet will shade many containers...I guess you could use anything to shade them as long as it doesn't transfer the heat to the container.

Happy Gardening

Thanks for the input! I guess the famous red tomato mulch was a waste of money (not that I thought it would help that much, but hey, on the off chance....).

The containers are sort of a medium light blue, I think the same color as yours, atascosa, but I don't think I will have to resort to shielding them as I know, being a former Texan, your sun is much more intense that here in NC. But I definitely will keep that in mind, if replacing the plastic mulch with white doesn't do the trick.

Thanks again, guys.