By Debra Levey Larson
Media/Communications Specialist, University of Illinois College of Agricultural, Consumer and Environmental Sciences
URBANA, Ill. — If your lawn hasn’t looked its best this summer, now is the time to do something about it. Seeding in late summer — August to September — has a much higher success rate than seeding in spring.
“Warm days and cool nights, combined with more regular rainfall, are ideal conditions for seedling growth,” said Rhonda Ferree, horticulture educator with University of Illinois Extension. “Also, there is less weed competition at this time of year.”
The first step in seeding a lawn is to prepare the seedbed. A well-prepared seedbed is essential for rapid, successful establishment of a lawn, said Ferree.
Start by removing all debris from the lawn area, including large rocks, gravel, building materials and roofing. Do not bury debris, because it can interfere with water movement.
If needed, add soil amendments to the area. These might include organic matter, topsoil or pH adjusters such as lime or sulfur, based on soil tests. Spread organic matter or topsoil to a minimum of 2 to 3 inches over the area, and rototill the site. Rake the area smooth, again removing any debris that may have surfaced during rototilling.
“If you are overseeding an existing lawn, rake the area by hand or with a vertical mower to remove old plant debris. Then, you can add soil amendments if they are needed,” Ferree said.
Broadcast a complete fertilizer with a 1-1-1 ratio, such as 10-10-10 or 5-5-5. “You will need to apply 1 pound of actual nitrogen per 1,000 square feet. Apply it evenly over the entire area, then rake lightly to incorporate the fertilizer into the soil,” she said.
Second, choose a quality seed for your lawn. Ferree said this is particularly important if you had problems with turfgrass disease in the past. Select a grass seed mixture with resistance to various diseases. This is often more expensive, but paying more up front will save you time and money in the future.
Spread the seed in two directions, dividing it into equal portions. This ensures uniform seed distribution. Lightly rake the seed into the soil, and roll the entire area. This is for good seed-to-soil contact.
Third, wait for impending rain, or water it yourself. New lawns are often seen with a layer of straw, but Ferree said it’s not necessary, although a light layer does help keep the seed moist.
“Seeds absorb and hold moisture, reaching a point where they burst open,” Ferree said. “Dry periods can cause reduced germination rates and seedling growth, so you need to keep the seed and young seedlings moist. Light watering two times a day, if not supplied by rainfall, should be sufficient, but every spot is different, so check the area often.”
Finally, start mowing with a sharp mower blade when the grass is between 2 to 3 inches high. Mow regularly and often. “You can lightly rake off the mulch, but be careful,” Ferree said. “If the soil is dry, try not to pull the young seedlings out of the soil.”
For more lawn care information, including recommended grass cultivars, visit http://urbanext.illinois.edu/lawntalk/.
From the Aug. 31-Sept. 6, 2011, issue