Generally, late summer and fall is the time to think about overseeding your lawn. If you have areas that are patchy, not as green as you like, or otherwise suffering, then overlaying the lawn with fresh seed provides an easy option for rejuvenating the lawn. 

1.  Open Up the Soil

Compacted soil or soil covered in a heavy thatch layer of dead organic material doesn't allow for satisfactory seed germination. Before overseeding, the lawn needs to be dethatched using a dethatching rake to pull up the buildup of dead grass and other debris. Next, use a core aerator to open up and loosen the soil throughout the lawn. These tasks can be done at any time in the season before you plan to overseed.

2. Mow the Grass

The lawn needs to be mowed on the day of overseeding. Cut the grass to the same length that you usually cut. The grass clippings should be removed from the lawn, though; otherwise, they may prevent the seed from sifting down to soil level. Either use a bagging mower to collect the clippings, or rake the lawn well after you are done mowing.

3. Fertilize Properly

The newly germinating seed will need to be able to access nutrients in the soil in order to quickly put on healthy new growth, but the new seedling will need to compete with the existing grass to get those nutrients. Applying fertilizer before you begin to overseed will add those nutrients. Choose a standard lawn fertilizer, but opt for a slow-release variety, as otherwise, the excess nutrient availability may damage the young grass seedlings.

4. Water Properly

The seed must be moist in order to germinate and begin growing. Prior to seeding, water the lawn deeply so that the top layers of soil feel moist but not soggy. Watering also helps to activate the fertilizer while driving the nutrients deeper into the soil so they will be available to the developing grass roots instead of sitting on the surface and burning the lawn.

5. Choose a Seed Type

The last task before overseeding is to pick the right type of grass. You can use the same type of grass as what is currently growing, or you can choose a different grass that helps counteract the shortcomings of the current lawn. For example, if you currently have a cool season grass that browns out in the summer, consider overseeding with a warm-season grass that will help keep the lawn green when the other type goes into dormancy.

Contact a lawn care service for more information about overseeding your lawn.