The Best Time Of Year To Overseed Your Lawn

If your grass is looking a little ragged or patchy, overseeding your lawn can be a good way to fill in bare spots and refresh its appearance for next season. Overseeding refers to sowing the seeds of a different species into your lawn to improve its durability and appearance. Many gardeners also use the term to refer to sowing seeds of the same species of grass that's already in the lawn — though, that's technically a different technique called interseeding.

Whether you're overseeding or interseeding, the key is to time it by the species of grass you're sowing into your lawn. For cool-season grasses, like fescues or Kentucky bluegrass, the best time to reseed your lawn is late summer or fall. For warm-season grasses, on the other hand, you should wait until spring or early summer.

In addition to getting the timing right, it's a good idea to address the underlying problems that are causing your lawn to get thin or patchy. If the issue is that the species you have isn't well-adapted to your climate, you can overseed with one that is better suited to your region. For southern lawns, that might mean mixing some warm-season grasses into your fescue lawn. For northern lawns, look for cool-season grasses that boast better cold tolerance. If the species is right, but you're still getting thinning in areas, it's likely caused by sub-par conditions. So, you can overseed with the same species, but make sure to apply compost or use other strategies to fix the underlying problems that are preventing your lawn from thriving.

For cool-season grasses, the best time to overseed or reseed your lawn is in late summer or early fall. This is when the soil is still warm but the temperatures are starting to drop below the peak heat of summer that cool season grasses are less able to tolerate. The seed will have enough time to establish its roots before going dormant after the first frost. There will also be less competition from weeds this late in the season.

If you're overseeding zoysia grass or another warm-season grass, the best time to reseed your lawn is in spring or early summer. These species can be slow to establish, so giving the new seed the full warm season to germinate and grow is important. However, that does mean you'll be dealing with more competition from weeds while getting it established.

With that said, some gardeners in warmer climates like to overseed their lawn in fall with a winter annual like ryegrass or a cool-season grass that normally wouldn't survive the summer heat. This can give you a green lawn through the winter that dies out come spring, just as your warm-season grass is ready to wake up. If you do this, there's a risk that the temporary grass could compete with or shade out your warm-season grass. So, it's important to keep it mowed short, to a height of about 1 inch. You should also limit water and fertilizer so the temporary lawn is weak enough to allow your permanent grass to outcompete it come spring.