Question:
There are areas in my lawn where the grass is rather sparse. How do I fix these areas?Answer:
The thin areas can be repaired by overseeding. Overseeding is the sowing of grass seed into an existing lawn. In Iowa, late summer (mid-August to mid-September) is the best time to overseed a lawn.
Good site preparation is necessary for successful overseeding. Small areas can be prepared by gently raking the thin spots. The objective is to break the soil surface without pulling out the existing turfgrass. After raking, sow the seed by hand. Then work the seed into the soil by gently raking the areas a second time.
Large areas can be prepared by using a core aerator. Core aerators are machines with hollow metal tubes or tines. They remove plugs of soil when run over the lawn. To prepare the site, go over the lawn 3 or 4 times with the core aerator. When finished, there should be 20 to 40 holes per square foot. Apply the seed with a drop seeder. Afterward, drag the area with a piece of chain link fence or drag mat to break up the soil cores and mix the seed into the soil.
To encourage germination, keep the seedbed moist with frequent, light applications of water. It’s usually necessary to water at least once a day. The grass seed should germinate within 2 to 3 weeks.