I've seen old tractor tyres used as planters before now...
they don't have to be tractor tires to be used as planters. I use my old tires to make raised beds in my garden, 3 car tires tall is perfect height for gardening, peppers especially, like raised tire beds, 2 plants to a stack, a teaspoon of Epsom salts every now and then, and ya be growing jalapenos by the bushel, they really like the warm soil from the sun hitting the tires
I use my motorcycle tires as potato planters. as the plants grow, add another tire and mulch to fill, at the end of the season, a 100lbs of taters in the stack