Autumn Lawn Care Basics

James A. Murphy, Ph.D., Extension Specialist in Turfgrass Management

Autumn brings cool temperatures, short days, beautiful colors and plenty of leaves!  Cleaning up leaves from both the lawn and street is important.  Leaves need to be removed from the lawn or mulched into the lawn to prevent smothering of the grass plants.  As little as one to two weeks of cover by tree leaves will cause thinning of the turf and eventually extended leaf cover will lead to failure of the turf.  Leaf and other tree litter lying in the street also present an environmental risk to our streams, rivers, ponds and lakes.  Autumn rain storms can wash this organic debris through the storm water drainage system into our waterways increasing the possibility of eutrophication (excess phosphorus and nitrogen in the water).

Soil testing will determine the degree of soil acidity and amount of available plant nutrients, which is used to produce a recommended amount of lime and fertilizer for your lawn.  See Rutgers Cooperative Extension (RCE) publication FS797, Soil Testing for Home Lawns and Gardens, and http://njaes.rutgers.edu/pubs/publication.asp?pid=FS797 for more information about getting your soil tested.  Lime is best applied in the autumn and early winter seasons.  When done properly lime will not need to be applied every year. Autumn is the best time to fertilize lawns (cool season turfgrasses) and in many cases should be done every year.  Fertilization at a nitrogen rate of 1 to 2 pound per 1000 square feet in autumn is a highly effective at improving turf density and color not only in autumn but next spring as well.

Protect water quality - do not apply fertilizer too close to streams, ponds and lakes where you may inadvertently misapply fertilizer into the water.  Also, clean up any fertilizer applied to sidewalks, driveways, streets, and other impervious surfaces to prevent fertilizer from washing into nearby storm sewers and bodies of water during intense rainfall.

Dethatching vigorous dense lawns that have accumulated a thick layer of organic material (thatch, consisting primarily of roots and rhizomes) on the soil surface and below the green leaves can improve the stress tolerance of the lawn.  Autumn is an ideal time for dethatching.  Too much thatch in a lawn may be an indicator of excessive nitrogen fertilization and/or watering.  Reduce these inputs if an overabundance of thatch develops.  See FS740, Thatch Management in Turf http://njaes.rutgers.edu/pubs/publication.asp?pid=FS740 for more information.

Mowing height can be lowered safely during autumn typically no lower than 1 ½ inches.  Lower mowing can help with leaf clean-up and encouraging the lawn to thicken (increased shoot density).  Mow as frequently as necessary to remove no more than 1/3 of the leaf height in a single mowing.  During warm autumn weather, a lawn will benefit from mowing into late November or early December.  Removal of clippings imparts a neater appearance to the lawn; however it is usually not necessary to remove clippings.  Returning clippings to the lawn recycles nutrients to the soil and grass and also reduces waste.  Mulching mowers facilitate this by chopping the clippings into smaller pieces.  Contrary to the widespread misconception, returning clippings does not contribute to thatch accumulation.

Watering your lawn is generally not necessary during the later months (November and December) of autumn.  Automatic irrigation controllers should be shut off and the system winterized by November.  See FS555, Best Management Practices for Watering Lawns at http://njaes.rutgers.edu/pubs/publication.asp?pid=FS555 for more information.

Diagnosing Lawn Problems requires expertise in the recognition of characteristic symptoms and signs of the problem.  When a problem develops, immediately arrange to have the trouble diagnosed to determine appropriate treatments.  You can contact the RCE office in your county for assistance in diagnosing problems; listed under county government in the phone book or at http://njaes.rutgers.edu/pubs/search.asp?cat=9999&searchstring=county+offices.

Note: all fact sheets referenced can be downloaded or can be obtained from your county RCE office.