Check it out. Aluminum tape! 26' roll at 99cent store. Takes 1.5 rolls per 15 gal pot.
Keeps your soil cool for hot climates with long exposures.
Looks like it would help. Do you know how long it holds up?
No idea, but if you can find a way to encapsulate the al foil tape, maybe selophane, it might just last for a few years?
I know my white duct tape is in its second year, and still doing OK