Stormwater: Making the Cut

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Summer is upon us and that means that lawnmowers are running and running.  Most urban yards are within only feet (or inches) of paved streets and storm drains. Responsible mowing and proper lawn care techniques will keep grass clippings and chemicals out of the storm drains and ultimately out of our rivers and streams.

A good rule of thumb when mowing with a mulching or standard mower is the “1/3 rule”. Mow the lawn often enough so that no more than 1/3 of the length of the grass blade is removed, leaving the grass about two inches tall. Cutting your lawn lower than two inches or “scalping” it will decrease your lawn’s ability to absorb water and nutrients. Grass clippings will be short enough to be left on the lawn as fertilizer and to hold the moisture in.  Clipping can also be raked and composted in the backyard to become mulch. Never rake or blow grass clippings into the street and be sure to keep piles away from streets and drains and also covered if sitting for a period of time.

If possible, avoid chemical use when caring for your lawn. Conduct soil tests to see if fertilizers are needed before applying.  If fertilizers or herbicides are used, avoid using them several hours before a rain and avoid use near local waterways. Fertilizers are best used in consecutive applications of smaller doses. This allows your lawn to absorb the nutrients and will not burn the root system by overloading it. There are a number of eco-friendly fertilizers on the market that are less harmful to the environment.  These typically have:

  • 50% or more of the nitrogen is slow-release
  • Low or no phosphorus (N to P ratio is 5:1 or greater)
  • Pesticide free (no weed-and-feed)

If fertilizing is necessary, one chemical application in the fall will produce better results than several applications throughout the summer months. Fertilizing with mulched grass clippings or compost will add nutrients and moisture giving your lawn the same benefits and will be less of a risk of stormwater pollution. By following these simple steps, lawns will be healthy and so will our rivers, lakes, streams, and ponds.

For more information on stormwater pollution prevention, please visit our website:, the Office of Environmental Quality website:, or call the Stormwater Management Department at (513) 732-7880. 

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