Category: Cooperative Extension
Fall is for Lawns
September 04, 2020 Written by Sue Barton
Now is the time to renovate your lawn.
You may have heard that lawns are not great providers of ecosystem services — that is true. Like any plant, lawns take up carbon dioxide and give off oxygen (an ecosystem service for sure), do little to support wildlife, improve water quality or manage flooding and erosion. Lawns provide a way to circulate through the landscape; they provide a gathering space and support lots of sporting activities. They are also the green carpet that stitches together the rest of the landscape. Since lawns are so important, we should decide where lawns go first when planning the landscape and then the rest of the property must become something else (landscape bed, vegetable garden, meadow, forest, patio or deck).
So when planning a lawn or renovating an existing lawn, start by deciding where the lawn is needed. Once you have determined the optimum lawn space on your property, you are ready to make that lawn as attractive and functional as possible. For many of us, that may mean renovating the existing lawn. Many lawns are choked with weeds or grown on compacted soil and late summer is the time to fix those problems.
Why now? This is the beginning of the best time to renovate (or start) a lawn because the soil is warm, promoting seed germination, but as the young grass begins to grow, the weather will become cooler into the fall, promoting good growth. Another benefit of fall seeding is fewer annual weeds are plaguing the lawn in the fall. After the first frost, summer annuals will die out and while there are a few winter annual weeds, they do not cause too many problems in a home lawn.
If your lawn is weedy, you will need to control those weeds first. If you have more than 50% weed cover, it may be best to kill all the existing vegetation and start over. With a few weeds, you can use a selective herbicide that targets your problem weeds. Be sure to read the label and use the appropriate product. Compacted soil can be fixed in late summer as well. Use a core aerator to pull plugs out of the soil and top dress with compost. With a complete renovation, you may want to use a rear tine rototiller to loosen the soil — regrade with a stiff rake after tilling to get a smooth final grade.
Once you have thoroughly prepared the site, spread new grass seed. Throughout all of Delaware, the best grass to use is turf-type tall fescue. It is tougher, more drought tolerant, less prone to disease and the newer cultivars have an attractive leaf blade. For specific variety recommendations, use this Extension fact sheet — Turfgrass Selections for Delaware.
Cover your newly seeded lawn with a thin layer of salt hay or straw to reduce evaporation. Keep newly seeded areas watered. Once the grass has grown to about 3-4 inches, cut it to 2 1/3 — 3 inches. Be sure to sharpen your mower blade before cutting. A dull blade will pull tender grass seedlings out of the ground. You can add about 1 lb of nitrogen per 1000 square feet to the lawn to promote growth. When you fertilize in the fall, you encourage growth root more than shoot growth, perfect for newly established lawns.
Finish your lawn renovation by Oct. 15 (Oct. 30 at the latest). After October, the soil is too cold for seed germination and the day length is becoming too short for good growth.
For more details about managing a healthy lawn and the renovation/establishment process, refer to this Extension brochure — Livable Lawns — Managing a healthy lawn.