Can You Overseed During Winter?

It's easy to think that you only have to worry about lawn maintenance during spring and summer when you keep the grass cut. To get the most out of your lawn, though, you should maintain it throughout the year. In addition to applying lawn fertilizer in spring and periodically aerating compacted soil, overseeding during fall or winter keeps your lawn beautiful and makes it easier to maintain.

Overseeding plays an important part in keeping your yard green, healthy and free of weeds. When you overseed your lawn, bare and thinning spots fill in with new grass and your existing grass becomes lush. This in turn increases competition for weeds seeking light and nutrients, with the thicker carpet of grass shading the soil and preventing many weeds from becoming established. Overseeding also helps ensure that your lawn grows evenly, with new grass reviving slow-growing areas of your lawn and giving it a more uniform look.

Before deciding to overseed in winter, consider the type of grass that you currently have in your lawn. Some grasses are known as warm-season varieties that grow throughout spring and summer. Other grasses are cool-season varieties that do much of their growing in the cooler months of the year. You should overseed your lawn while it is dormant, which typically means cooler fall or spring months for warm-season grasses and late spring for cool-season varieties.

While most warm-season overseeding occurs in fall or early spring, it is possible to overseed in winter as long as the ground isn't frozen. You can overseed cool-season grasses during the winter as well, though late summer and early fall is a more common overseeding period for these types because it gives them longer to mature before the heat of the next summer begins.

During a mild winter, you can overseed at any time as you would in fall or spring. However, if the ground temperature frequently drops below freezing, timing becomes more critical. Seeding should occur before a freeze or just as the ground begins to thaw, allowing the seeds to take advantage of the natural expansion and contraction of the soil as it moves from frozen to thawed.

Before overseeding, remove any thatch from the grass using a mechanical dethatcher or metal rake. Rake the soil with slight downward pressure or use a power rake on bare areas to create 1/4-inch grooves in the soil that increase the seed-to-soil contact area. Use a crank-operated seed spreader to sow seeds, walking north to south across your property and then repeating the sowing from east to west to ensure that seeds are sown from two directions. Don't water the new grass immediately after winter overseeding; allow the seeds to adjust naturally to lower temperatures, and then begin watering when temperatures start to rise and seeds begin to sprout.