There are insulated pots. You can also bury your pots so the ground naturally insulates it. Another option is to put it in a bigger pot and have something insulating the space between them. I've heard of styrofoam spray, but that it's difficult to use. Others might have more suggestions. Good luck!

I don't think the bottles will be very effective. If you block the sun's rays with something opaque -- like a piece of plywood or a board the height of the pots -- it will be much better. And it can't look any worse than a bunch of used plastic bottles sitting there.

Thanks for your input everyone! I'm thinking bigger pots with Styrofoam peanuts for insulation.

"And it can't look any worse than a bunch of used plastic bottles sitting there."

Well, considering that my part of the yard already looks like white trash city--that's the least of my worries :-) (Pumpkins hanging from panty hose for example.) It's a good thing I don't have any neighbors near my garden. Although, my DH shudders when he comes in that part of the yard. I think he likes to pretend that it belongs to someone else. No one else ever ventures back there besides the deer, peacocks and occasional snake.

And, using some of the clay pots laying around will actually improve the hoarder's clutter. Another project to work on in the morning. I think I have some of those peanuts some where.......

Lol! Those pumpkins sound interesting.

I've seen interesting pot stackings on pinterest. They installed a long pole into the ground and stacked the pots tilted around it, then grew plants in it.