Plant a vegetable garden in old automobile tires: put down a black plastic layer of 6-mil Polyethylene over the surface area of the ground where the garden will be. Place the tires side by side; fill each tire with soil. Plant a different vegetable in each tire. Try carrots (an "underground fruit"), broccoli (an "on-top-of-the-ground flower") and peas (a "vine"). Other fun plants are pumpkins, corn plants, potatoes, and peanuts.