Composting and Lawn Care - Brooklyn Botanic Garden
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Composting and Lawn Care

Leave it on the Lawn!

Leaving grass clippings on the lawn, rather than bagging and sending them to the landfill, makes sense for you, your landscape and your community.

Grass clippings are good for your lawn. For a healthy lawn and more money in your pocket, just follow these simple steps to leave the clippings on the lawn:

  • Mow grass when it is between 3" and 4" tall. Never cut it shorter than 2-1/2" to 3". This gives your lawn a healthier root system.
  • Never cut off more than 1". As a general rule, don't cut off more than 1/3 of the grass blade in any one mowing.
  • If the grass gets too high, mow over clippings a second time to further shred them, or raise mower height and gradually lower it over a span of several mowings.
  • Cut grass when it is dry. Avoid mowing wet grass, since wet clippings mat together.
  • Use a sharp mower blade. Dull mowers use more gasoline and can give the lawn a frayed appearance. Generally, mower blades should be sharpened every year.

Any mower can recycle grass clippings; you do not need to purchase a special mower. Simply remove the grass catcher. (If you have trouble using your mower without the catcher, contact a dealer for help.) Kits are available to convert some bagging mowers into mulching mowers. There are "recycling" or "mulching" mowers manufactured specifically for leaving clippings on the lawn.

General Lawn Care Tips

  • Aerating your lawn once a year will open up the soil and permit greater movement of water, nutrients, and air.
  • This makes the grass clippings decompose faster.
  • Don't water the lawn unless it really needs it. If you choose to water, water thoroughly and less frequently.
  • Water in the morning to minimize evaporation. Avoid watering in the evening, because a lawn that remains damp during the night is more prone to disease.
  • Use a slow release or natural organic fertilizer and do not over-fertilize.
  • As a general rule, apply 1/3 of your fertilizer around Memorial Day, 1/3 around Labor Day and 1/3 before Thanksgiving. Late-season fertilization will promote healthy root growth.

Other Easy Alternatives

If you don't want to leave clippings on the lawn, use one of the following options:

  • Use clippings as mulch around plants and shrubs. Apply a 1 " layer of clippings to reduce water evaporation, eliminate weeds and enrich the soil.
  • Add clippings to your compost pile; they are an excellent source of nitrogen. Clippings should be mixed thoroughly with leaves or old compost.

Facts About Grass Mulching

  • Lawn chemicals, such as pesticides and fungicides, can kill beneficial earthworms and micro-organisms which are important to the health of your lawn.
  • Grass clippings are 85% water and 5% nitrogen. When left on the lawn, they return water and nutrients to the soil. Grass clippings can provide up to 30% of your fertilizer requirement.
  • Grass clippings left on the lawn do not cause thatch. Thatch is caused by rapid and excessive growth due to over-fertilization and improper watering.
  • Grass clippings left on the lawn reduce water evaporation and keep the soil cooler during hot weather.
  • Because they are mostly water and nitrogen, clippings contribute to gas and leachate problems when buried in a landfill.
  • Grass clippings account for 2% of the waste stream. Bagging and disposing of clippings takes up precious landfill space and adds millions of dollars to New York City's disposal costs every year.

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Image, top of page: Antonio M. Rosario