All About Grass Clippings

Grass clippings from lawns can be an asset to your lawn and garden or a detriment to your lawn, lakes and rivers. The key is when they are cut and where they go after they are cut.

Grass clippings are a valuable source of nutrients for the lawn. Clippings must be 1” in length or less to easily fall back to the soil and decompose quickly. Adding these clippings to the soil can improve your soil’s organic matter and health.  Grass clippings longer than 1” may stay on the lawn looking unsightly and smothering the grass below.  These longer clippings should be removed and either composted at your home or taken to the compost center.

Since getting shorter clippings means mowing your lawn more, you could consider reseeding your lawn with a “low mow” grass. Low mow grass mixes are a mix of slow growing fescues. Fescues are slower growing, drought and shade tolerant with finer, softer leaves.  You can reseed a traditional lawn with fescue seeds if you reframe from irrigating the lawn, the fescues will outcompete the existing grass over time.

There is a myth floating about that leaving grass clippings on the lawn contributes to thatch on the lawns. It doesn’t. Thatch is a layer of undecomposed organic matter that builds up between the soil surface and the actively growing green grass. Thatch appears if organic matter is being produced faster than it is being decomposed by micro-organisms.  This is caused by excessive nitrogen fertilizing, infrequent mowing and low soil oxygen.

Clippings can make great mulch around plants in annual or vegetable gardens. Mulching helps reduce weeds, conserves moisture, and modifies soil temperatures. Do not apply more than 1 or 2 inches of grass clippings at one time and do not use grass clippings as mulch if the lawn was recently treated with an herbicide for dandelions or other broadleaf weeds.

Where clippings should never be left is on your driveway, street or sidewalk. Clippings on these hard surfaces will wash off with the next rain and flow into the nearest lake, river or pond. Instead of adding fertilizer to your lawn, washed away grass clippings will add nutrients to lakes and rivers, causing algae growth.  Always be sure to sweep or blow grass clippings back off hard surfaces and back on to the lawn.  Your lakes, rivers and lawns will thank you.