Autumn will soon be here—the equinox is September 22 this year. And while we participate in many pleasant activities during its bright, crisp days, autumn also brings a less pleasant chore, dealing with leaves. Whether you pile, compost or bag them, there are some best practices to keep in mind to protect water quality and your local infrastructure. 

  1. Keep leaves out of the street and away from storm drain inlets. Leaves left in streets get blown by wind and carried by rainwater to the nearest street drain. They form thick mats both inside and on the grate of the stormwater inlet and cause street flooding. Municipal employees must then vacuum the storm drain before its scheduled cleaning, causing unneeded expense to the public utility.
  2. If you use a professional landscaper to maintain your yard, request that when he or she uses the leaf-blower to clean the sidewalks or driveway, it is directed back into the yard and not into the street.
  3. If your community has curbside leaf collection, rake leaves to the grassy area between the street and the sidewalk or to the edge of your lawn, if there are no sidewalks. Do not rake or blow leaves into the street. “Leaf piles will not kill grass, although they may cause it to temporarily discolor. The grass will grow back, rich and green, in the spring. To prevent grass from discoloring, rake your leaves immediately before your scheduled pickup date.” (from the City of Dublin Guidelines for Safe and Efficient Leaf Collection)
  4. If your community has curbside yard waste recycling, remember to put the leaves in trash cans marked “yard waste” or in the large paper bags sold for this purpose at grocery, hardware and home stores. Leaves will not be collected if they are in plastic bags.
  5. If you live along a ravine or stream, do not dump your leaves “over the edge.” The leaf piles will form thick mats that won’t decompose over the winter. The vegetation under the leaf piles will then die, leading to erosion on the streambank or ravine. Erosion leads to water quality problems and loss of property as the bank slides, slumps or becomes undercut by high water.
  6. The other water quality problem with leaves being introduced into streams, either through the stormwater system from street drains or through dumping over streambanks, is the depletion of oxygen that can kill fish and other stream organisms. When organic matter decomposes in streams, bacteria use up the dissolved oxygen that is needed for aquatic organisms to live. This process is what causes the “dead zones” in the Gulf of Mexica and Lake Erie.
  7. Composters can add leaves to their bins, but the high C/N ratio requires mixing with high-nitrogen ingredients for best results. If you cover your vegetable garden with leaves, it will likely require added nitrogen in the spring. Either way, leaves will decompose much faster if you run over them first with a mulching lawn mower. Those planning to compost kitchen scraps during the winter should save dried leaves in plastic bags in the garage so they will have a “brown” material to cover the food scraps over the winter. This will also provide a handy “brown” in the spring, when there are lots of “greens” but fewer “browns” to mix.
  8. According to OSU Extension, “Walnut leaves can be composted because the toxin breaks down when exposed to air, water and bacteria. The toxic effect can be degraded in two to four weeks.”
  9. Leaves can also be used as mulch. According to University of Minnesota Extension, “Leaves make an excellent mulch for use around trees and shrubs, or in flower and vegetable gardens. They help retard the growth of weeds, help retain soil moisture, help maintain lower soil temperatures in the summer, and protect against temperature fluctuations and some types of low temperature injury during winter. They eventually decompose, adding their nutrients to the soil and improving soil structure.”