Got a dead houseplant? There's no need to toss it into the trash, where it won't have a chance to biodegrade in the landfill. In fact, even though it's dead, it can help create healthy soil in your yard or garden. Remove the dead plant and shake off the excess potting soil. Use a lawnmower to pulverize it into smaller pieces. The organic matter can be added to a compost bin or sprinkled on the yard, where it will naturally decompose in no time.