I always associate the arrival of fall with its cooler temperatures as not only a time to enjoy the fall colors and to begin to think about cleaning up the gardens but also a time to think about lawn repair.
Now rather than spring is the best time to renovate and seed lawns because there is less competition from weeds. Young grass will have two cool growing seasons before having to cope with the stress of next summer’s heat. Since lawn renovation is time consuming and moderately expensive it should not be performed unless steps are taken to correct the underlying cause of turf deterioration. Some causes that come to mind are drought, excessive shading, tree root competition, poor drainage, compaction of the soil, inadequate fertility, acid soils, weed or insect infestation, diseases, thatch buildup, improper mowing, and poorly adapted grass species and cultivars. In most of these cases the problems can be corrected by renovation, proper turfgrass selection, and improved maintenance practices. Lets look at some of the causes of turf deterioration.
Shade problems may require removing some trees and pruning, and planting turfgrass species that are adapted to shaded conditions. Tree roots may need pruning to reduce competition with grasses for water, air, and nutrients. We fought this battle when we lived in Park Forest.
Drainage problems can often be corrected by breaking up a compacted soil or through installation of drainage tile. Where surface drainage is somewhat insufficient, the site may have to be re-graded so that water is removed from the site.
In the case of inadequate soil fertility and soil acidity that can certainly limit the growth of your turf, it is important to take a soil test. Soil testing services are available from the Agricultural Analytical Services Laboratory at Penn State or through private laboratories. Mailing kits for the soil tests are available at a nominal fee from the Penn State extension office in your county. Soil test laboratories will then provide a recommendation for the amounts of fertilizer and lime that need to be applied to your lawn.
Insect, disease and weed pests can cause serious turf damage need to be identified and controlled. If you cannot identify these pests, take fresh samples to your county extension office or another knowledgeable source to have them identified. The Penn State Cooperative Extension publication Suggestions for Turfgrass Pest Control contains information on controlling turfgrass pests. There are a number of other publications and websites that have great color photos with information on control measures to employ.
The definition of thatch is a tightly intermingled layer of partially decomposed grass stems and roots that develops beneath the actively growing green vegetation and above the soil surface. Thatch can decrease the vigor of turfgrasses by restricting the movement of water, fertilizers, and pesticides into soil. Turfgrass roots also grow into the thatch and may become desiccated as the thatch dries. Thatch builds up over a period of years and must be periodically removed by mechanical means. Thatch removal equipment can usually be rented from garden centers or rental outlets.
Proper mowing is a common problem on most lawns. Mowing height should be at two inches or above on a regular basis as long as the grass is growing. How frequently the grass is mowed depends on the growth rate of the grass. No more than one-third of the total leaf surface should be removed at a given mowing. Thus, if turf is cut at two inches, it should be mowed when it reaches a height no greater than three inches. Clippings do not need to be removed provided the lawn is mowed on a regular basis. It is important that all mowing equipment is sharpened and adjusted periodically.
The use of unadapted species and improper management is another common cause of turfgrass deterioration. Species of turf and management must be adapted to the conditions present.
As you can see there are many underlying causes of turfgrass decline so figure first what is causing the problem then go to the next step of renovation.
Bill Lamont is a professor and extension vegetable specialist in the department of plant science at Penn State. He can be reached at firstname.lastname@example.org.