Leave Grass Cuttings on Your Lawn

Grass cuttings and other yard waste (leaves, tree and shrubbery prunings) make up 12 percent of the solid waste sent to American landfills. The amount can exceed 50 percent during peak grass cutting and leaf collection times in some parts of the country.

The myth that allowing grass cuttings to stay on a freshly mowed lawn will damage the lawn still persists in the minds of many homeowners and others who are responsible for maintaining grassy areas, even though research has proven otherwise. Cut grass clippings are a source of free, nutrient-rich fertilizer for consumers. Throwing away cut grass clippings not only overburdens landfills, it is also costly: millions of taxpayer dollars are spent to collect and transport this organic fertilizer to the landfills.

The environmental benefits of keeping cut grass clippings on lawns are considerable, according to the Department of Horticulture at the University of Missouri:

• Grass clippings contain 80 to 85 percent water and decompose quickly when left on the lawn. The clippings also help keep moisture in the soil longer, reducing the need for frequent watering (saving both water and money)
• Up to 25 percent of a lawn's total fertilizer needs can be met if grass cuttings are left on the lawn. The clippings slowly release essential nutrients—nitrogen, potassium, phosphorus, and minor elements — slowly so the lawn is continuously being fertilized. Well-fertilized lawns need less water.
• Average lawn mowing time can be reduced by 30 percent when grass cuttings are not bagged.
• Contrary to myth, grass cuttings do not cause thatch problems.

From now on, you can have a healthy lawn that saves water, time, landfill space, and money. Here's how...

• Mow the grass often enough so that no more than one-third (about 1 inch) of the vertical height of the grass is cut each time. This leaves a healthy amount of grass cuttings on the lawn and also helps support a healthy root system, which translates into a lawn that is more drought resistant and less needy of water.
• Mow grass when it is dry. Cutting wet grass creates clumps, which can accumulate on the lawn and damage it.
• Keep your lawn mower blade sharp. A dull blade damages grass and increases the possibility that insects and disease will move in.
• If you have extra grass cuttings, spread them in thin layers in vegetable and flower beds or around the base of trees as mulch.
• Extra grass cuttings can also be mixed with leaves and used as mulch around shrubs in the fall.
• If you have not yet convinced your neighbors to leave their clippings on their lawn, ask if you can use the grass for mulch or for your compost bin.

A mulching mower cuts grass blades into smaller pieces than does a regular rotor mower, although it is not necessary to use a mulching mower when leaving grass cuttings on the lawn. For more information on lawns and the benefits of grass cuttings, the Virginia Cooperative Extension offers details as well as tips on how to use excess clippings in compost.