Overseeding can make a big difference in the look and health of your yard, but naturally, timing is everything. Seed too early or too late, and your grass may struggle to grow. The best time to overseed depends on where you live, what type of grass you have, and the weather conditions in your area. Whether you’re filling in bare spots or thickening up an aging lawn, knowing when to reseed can help you get the best results.
Best Times to Overseed – Based on Grass Type
Grass falls into two main categories: cool-season and warm-season grasses. The type of grass you have determines the best time to reseed.
- Cool-season grass (like fescue, bluegrass, and ryegrass) grow best in cooler temperatures. The best time to overseed is late summer/early fall, when the soil temperatures are still warm, but the air is cooler. This gives the seeds time to establish before winter. Spring overseeding is possible but can be tricky because the grass may not have enough time to develop strong roots before summer heat kicks in.
- Warm-season grass (like Bermuda, zoysia, and centipede grass varieties) thrive in hotter temperatures. Late spring to early summer is the best time to overseed since these grasses grow actively in warm weather.
If you're not sure what type of grass you have, a lawn care professional, local garden center, or extension office can help you figure it out.
Can You Overseed in Spring?
Spring seeding is possible... if you can get things to work in your favor. The biggest concern is competition with weed seeds. As air temperatures rise, weeds start growing aggressively, and new grass may struggle to compete. Another issue is the early summer heat. If seedlings don’t have time to establish deep, healthy roots, they can dry out or die in hot weather.
If you need to overseed your lawn in spring, here are some tips to improve your chances of success and healthy growth:
- Seed early in the season, so grass seedlings have time for active growth before summer.
- Choose a high-quality, premium grass seed that matches your existing lawn.
- Keep the soil moist but not soaked while seeds germinate.
- Avoid using weed control products until new grass and root growth is well established.
- Set your lawn mower to higher blade settings to protect young sprouts from drying out.
While spring overseeding can work, fall is usually the better option for cool-season grasses.
How to Tell If Your Lawn Needs Overseeding
Over time, lush lawns naturally thin out. If your grass isn’t as thick as it used to be, overseeding can help fill in gaps and get you back to overall healthy turf. Here are some signs your lawn might need reseeding:
- Bare or thin patches that don’t recover on their own
- A yard that looks dull, weak, or worn out
- Increased weed growth due to weak or dead grass coverage
- Heavy foot traffic areas that have thinned out
- Older lawns that haven't been reseeded in several years
Overseeding can breathe new life into a struggling lawn, making it thicker and more resistant to weeds and disease, and improving your home's curb appeal.
FAQ
Can you just throw grass seed on an existing lawn?
Yes, but results won’t be great. Grass seed needs good soil contact to germinate. If you toss seed on top of the entire lawn without preparing the layer of soil, most of it won’t grow. For better success, mow it shorter, remove grass clippings and debris, and use a core aerator to loosen the soil surface before spreading the seed.
How long does it take for overseeded grass to grow?
Germination rates depend on the type of grass, weather conditions, and soil conditions. Most grass seed takes 7-21 days to germinate. During this time, it’s important to water and keep the soil moist. If it's dry, it's gonna die! Full results can take several weeks to months, depending on growth rates and care.
How much seed do I use?
Normally, premium grass seed packages tell you the appropriate seeding rate according to your broadcast spreader and pounds of seed per 1,000 square feet. Take a close look at the packaging before you spread the seed across your lawn.
