Cumberland Now Volume 1, Issue 8 - Page 22

The time to start or re-seed a cool season lawn is in the fall. You need good seed-to-soil contact and sunlight to spark seed germination and turf growth. If you have weeds in your yard, try a weed killer before overseeding. This can increase your chance of success with the new grass seed. Timing is important. Check your labels to see how long to wait from using a weed killer and spreading new seed. time) to start or re-seed cool season lawn grasses on the Cumberland Plateau. Trying to establish a lawn from seed in spring or summer and/or overseeding mature turfgrass during those seasons is rarely successful here. Good seed-to-soil contact is very important. Sunlight also is important to good seed germination and turf growth. With an established but weedy lawn, I would use a weed killer before overseeding. By eliminating weeds 2-3 weeks before sowing seed the chance of success is increased. More grass seeds will fall to the ground rather than getting caught on the weed plants and the weeds won’t be there to shade the soil. I’d also cut the existing turfgrass short just prior to overseeding. Timing is important. Broadleaf weed killers that are fatal to weeds like dandelions yet don’t harm mature turfgrasses can injure young grass plants. Grass from a spring overseeding will not be hurt by such herbicides applied in September. However, with a reversed fall schedule – first overseeding followed by an application of broadleaf weed killer just weeks later — the new turfgrass may suffer harm. Examples of products for homeowner use that kill weeds but not the grass are Ortho brand WEED B GONE or Spectracide brand WEED STOP FOR LAWNS. Check the label on the product you choose to verify the wait-time between application of weed killer and safe reseeding and also to learn which weeds the product is formulated to eliminate. Fact sheets on weeds and methods to eliminate them are available at the University of Tennessee website www.tennesseeturfgrassweeds.org for download to your home computer. While climate change has brought more rainfall to our part of Tennessee in recent decades, we also experience sunny, dry periods with high temperatures that cause turfgrass stress. I chose improved fescue blends for my yard because KY bluegrass needs more water to combat drought stress and I don’t irrigate my turf. Kentucky 31 is an old fescue blend that I don’t recommend. Using blends that mix rye grass in with KY bluegrass or fescue seed is not recommended by UT. The website extension.tennessee.edu/publications also has information on lawns and various turfgrasses. The publication “Turfgrass Establishment: Turfgrass Seed” gives more details on different varieties and seeds. 22 | Cumberland Now • September 2020