Stormwater Program Fact Sheet #6

Chappaqua Central School District
66 Roaring Brook Road
Chappaqua, NY 10514 

MS4PY12 Stormwater Program

Fact Sheet #6
September 2021


For more information contact your stormwater coordinator:
Joe Gramando at
914-238-7210 x1201 or

Your maintenance staff is responsible for the lawns and gardens care. Fortunately, most school districts do not apply fertilizers to the district’s lawns and garden, Although, you may not be directly involved with the district’s lawn and garden care, you can apply the same BMPs at your home, relative to activities that make a big difference in preventing stormwater runoff pollution.

The steps outlined below will not only keep your lawn stormwater friendly but can result in direct and substantial cost savings.  

  • Adjusting Your Mower Height: Set your mower height to 3 inches or higher. The taller grass slows down the rate of runoff and will produce a deeper and denser root system. Deep roots will absorb more water, reducing the lawn runoff and preventing soil erosion. Deeper roots have access to more water stored in the ground and can reduce irrigation needs during droughts. Denser roots can also suppress weeds from growing up around them
  • Retain Grass Clippings and Chopped Leaves On-Site: A mulch mower is ideal for retaining and spreading clippings on your lawn. The clippings decompose quickly and provide important nutrients for your lawn, and settle to create an organic layer on the soil that encourages groundwater infiltration. This technique can significantly reduce and eliminate the need to purchase costly fertilizers
  • Keep Clippings and Leaves Away from Streams and Storm Drains: If mulching is not possible, bag the clippings and store them in a compost area or compost bin. Composting will decompose leaves and clippings into mulch, which can be utilized for soil enhancement and water retainage. Blowing clippings and leaves onto the street or into a storm drain, increases phosphorus and nitrogen, causing algal blooms, and producing an unsafe environment for fish and other aquatic life

Many lawns do not need fertilizers due to the soil fertility or due to steps described previously that the homeowner has implemented to maintain a stormwater friendly lawn. 

  • Test Your Soil: Soil fertilizer needs vary from one location to another, based on soil texture, pH levels and nutrient levels. Soils may be suffering from other micronutrient deficiencies than a lack of fertilizer. You need to test your soil s to determine if fertilizers are needed
  • Slow Release Nitrogen: Maximize slow release nitrogen in your fertilizer. Typically called “Water Insoluble Nitrogen” or WIN on fertilizer bags, slow-release nitrogen limits runoff of nutrients from your lawn
  • Proper Fertilizer Application:  Apply fertilizer in the spring rather than the fall, to provide a steady source of nutrients throughout the growing season. Wait until the grass begins growing in March to fertilize. Avoid fertilizing after October. Fertilizing during a lawn’s dormant season increases the risk of the fertilizer running off into streams or leaching into your groundwater table, because root systems are less active. Additionally, do not fertilize directly before a rain event, because most of the fertilizer will wash off in stormwater runoff
  • Fertilizer Application: Start with lower amounts and fewer applications in accordance to the manufacturer’s instructions. Your lawn may achieve its ideal coverage and growth with reduced application rates, saving time and money
  • Keep Away from Streams: Do not fertilize or apply pesticides and/or herbicides closer than 20 feet from a stream. Keep this distance to keep chemicals out of the stream. Consider establishing a natural vegetative buffer along the stream. This will absorb nutrients as well filter sediments that may enter the stream
  • Sweep Granulated Fertilizers and Other Chemicals: If you observe residual fertilizers or other chemical after application, promptly sweep your walkway, driveway, patio or local road to prevent discharge of fertilizers and other chemicals into your drainage pipes that discharge into local streams


  • Use fertilizers sparingly and test your soil.
  • Never fertilize before a rain storm
  • Consider using organic fertilizers, which release nutrients more slowly