Here are some cool ideas:
you could cut them in half, paint and use as edgers, lay them down paint and use as flower planters, or...set them up on bales of straw on their side, fill with dirt and plant full of tomatoes and such. This keeps most of the insects and animals out of them. I have used a raised garden many times..no sore back from bending to pull weeds!
I saw this on someone else's page the other day, in the gardening and outdoor living section and I loved it so much, I saved it. Hopefully, you like it as much as I do!
Like this one so much I'm Useing six old tires that have just been takeing up space along with some old paint. Thanks - And my husband thanks you, now he can put differant junk in there place.
Just be sure to drill holes in any tires you use. Standing water attracts all sorts of biting bugs.