They can also be added to the compost pile. Avoid mulching with grass that has been recently treated with herbicides that can harm your plants. Chemically treated clippings should be left on the lawn or composted where herbicides will break down. Use a mulch only after two months following herbicide application. When composting, do not use clippings alone.
Clippings mat together, depriving the compost microbes of oxygen and cause an odor.
It is essential, therefore, to mix grass clippings with leaves in a ratio of three parts leaves to one part grass clippings. Turning the compost pile with a pitchfork every few weeks will add oxygen to the compost and eliminate odors. If you can't use grass clippings in your yard, find a neighbor who might value them as a mulch or compost material. With collection and disposal costs at a premium, keeping you lawn clippings out of the garbage truck saves money and protects the environment. Research indicates that grass clippings left at mowing do not cause thatch in a lawn.