Most of the rubber mulch that you buy from the store is actually made from recycled rubber. Manufacturers collect old car tires, cut them up and charge you a premium for the service. But if you have a surplus of old car or bike tires, there's no reason why you can't make your own recycled rubber mulch for almost no money at all. Superior to organic mulch in many ways, rubber mulch insulates plants more effectively, allows water to reach their roots unimpeded, and reduces fungus and weed growth.
Use a sturdy pair of pliers and a chisel to pry the rubber tires away from from their steel belting if you are using car tires. Wear thick gloves to avoid being cut by the sharp steel belting. If you are using bicycle tires, move on to Step 3.
Rent an industrial grade shredder that is approved for use on tires. Cut the tires into manageable sections and insert them into the shredder according to the manufacturer's instructions. If you cannot access a shredder, use a sharp, serrated knife to cut the rubber mulch into manageable sections and then into small pieces that are roughly 1 square inch in size. Keep a knife sharpener on hand. The knife will need to be sharpened every few cuts to be effective.
Spray paint the rubber mulch. Spread the chips out over newspaper and spray them with one coat of a rubber-safe spray paint. Allow the paint to dry, then spray another coat. Flip the rubber mulch chips and spray them with two coats again.
Apply the rubber mulch to your garden. It only needs to be applied half as deep as traditional mulch.