Grass Clippings as Garden Mulch: Pros and Cons

Grass clippings are cheap. Why not use grass clippings as garden mulch? There are reasons why some gardeners use grass clippings as garden mulch and why others don't entertain the idea. Find out why gardeners make the choices they do, and decide if grass clippings are right for your garden.

Choice Against Grass Clippings as Garden Mulch

Grass clippings can compress into a mat of slimy stinky matter. Plant roots need air and water, and a mat of grass clippings depletes the soil of oxygen and moisture. In addition, freshly cut grass is hot. Have you seen steam rising from a mound of cut grass or hay? The heat of decomposition can do root damage to plants.

When people use herbicides, fungicides, and assorted chemical fertilizers on their lawn, grass clippings can introduce those chemical contaminants into the garden soil. This isn't a big deal where flowers and ornamentals are grown, but where vegetables and herbs are grown, it's a big deal.

Choice for Grass Clippings as Garden Mulch

Grass clippings insulate the soil in cool weather, keep the soil cool and moist in hot weather, and help conserve water. Furthermore, as the organic matter decays, it provides nutrients for beneficial microbes in the soil. Grass clippings also help control weeds, they are a very cheap mulch, and they decompose and add nitrogen to the soil. Gardeners who use grass clippings as mulch, do so for these reasons.

But gardeners who mulch this way, do so with caution. They allow the grass clippings to cool off or dry before applying the clippings as mulch. They may also compost grass clippings. When grass clippings are composted, they allow air and water into the soil. The clippings don't mat-up; they decompose nicely. To dry grass clippings, just spread out the grass clippings in the sun. When dry, loosely mulch near--but not touching plants. An inch of mulch is adequate, but never more than 3 inches of any mulch is needed.

Grass clippings left on the lawn mulch the lawn. As long as the grass clippings are not too long when cut, the mulch offers benefit to the lawn. Why not just leave it there? It's already providing a service. However, if you do decide to use grass clippings in your garden, be certain your lawn is chemical-free, the grass clippings are dry, and you loosely spread the clippings not more than an inch or two deep. You can use grass clipping for an inexpensive and effective mulch, as long as you remember these few suggestions.