Cut the side wells of one side of the tire off completely using a utility knife. Point the knife away from your body as you cut and wear protective gear: boots and gloves.
Fill the tractor tire with potting soil with the cut side facing up, to create a planter. Or, fill the tire with seed starter soil to plant seedlings. The rubber will help contain heat, acting as a hotbed for your seedlings.
Make a compost bin out of forklift tires. Cut the side wells off of six tires. Stack the remaining rings on top of each other to create a tall cylinder-shaped compost bin.
Fill the new bin with compost, turning each week with a pitchfork and checking with a temperature gauge that the innermost compost is between 135 and 155 degrees, the optimum temperatures for composting.
Build a retaining wall out of forklift tires by stacking a level wall of tires. The weight will help stabilize them, but for further durability, fill the tire wells with sand or dirt using a shovel.