How Often Do You Need to Overseed a Lawn?

If your neighbor's thick, lush lawn has you green with envy, it might be time to perform some routine maintenance on your own landscape. Overseeding—the process of adding new grass seed to existing turf—is a great starting point if you're looking to fill in thinning or sparse patches. "Many grass types lose density over time and require periodic overseeding," says Marc Mayer, the regional technical manager at TruGreen, who notes that you should aim to tackle this task annually. Below, Mayer explains why timing is everything when it comes to your lawn; he also shares other best practices for success.

Time it right.

Mayer advises against overseeding in the spring "due to weeds competing for space, nutrients, and water." Instead, he suggests putting down seed in the fall when soil temperatures are still warm, which also allows the seed time to "become more established" without the stress of summer heat.

Determine your grass type.

Before getting started, it's important to understand your grass type. If yours turns brown in the winter, then you likely have warm-season turf. Common varieties include Bermuda, Zoysia, Centipede, or St. Augustine, explains Mayer, all of which respond more favorably to sodding or sprigging opposed to overseeding. However, if you reside anywhere throughout the Midwest or Northeast where grass remains green through the winter months, then you're dealing with cool-season iterations, such as Kentucky Bluegrass, Tall Fescue, or Ryegrass.

Prepare for overseeding.

Once you've determined your type, it's time to prepare your lawn for germination. First, inspect your lawn for clumps of dead grass material, also known as thatch, as this will help ensure "good contact of seed with soil." Next, mow your grass to the shortest height your mower will allow, bag the clippings, and then rake your lawn in order to remove any leftover debris and loosen the top layer of soil. Then apply your seed.

Don't forget to water.

According to Mayer, "watering is one of the most important aspects of successful overseeding." After applying seed, a heavy watering is in order, after which a daily watering should be performed until seeds germinate, which can take up to two weeks. Once germination has occurred, continue to water thoroughly every few days. "It's important to keep the soil bed moist during the germination process or seed failure could be the end result," says Mayer, adding that it's also important to avoid heavy activity, such as mowing, on the delicate area.

Make it an annual practice.

"Annual overseeding is recommended to thicken lawns and make them more attractive, but also to introduce improved varieties of grass that are hardier, less prone to insects and diseases, and more drought tolerant," explains Mayer.