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Best Time to Reseed a Lawn

6 min read

Is your lawn in desperate need of a do-over? Too many weeds or bare spots and not enough healthy grass? It might be time to reseed your lawn.  

Reseeding at the right time allows your grass to grow healthy and strong, instead of struggling against the blaring summer sun, or cold winter days. Once you establish the best time to reseed for your grass type, you can begin growing a new lawn full of healthier, greener grass.

When to Reseed vs. Overseed

Reseeding is often confused with overseeding, which is the process of applying seed to your existing lawn to thicken up thinning areas in your yard. Reseeding, in comparison, involves first, killing the existing grass and weeds, then starting over with new grass seed.

While overseeding is a great way to thicken an existing lawn, Jonathan Green recommends reseeding a lawn when more than ½ of your yard is full of weeds or bare spots. 

Starting from scratch may seem extreme, however, reseeding is sometimes your only option if you don’t want to fight weeds for years to come. In order to have uniform, green grass, you have to hit the reset button and reseed your lawn. 

The Best Time to Reseed

The best time to reseed is unique to your type of grass and climate conditions. However, for cool-season lawns, the cool air temperatures and warm soil in early fall ensure proper seed germination. It’s important to time your reseeding project just right in order to achieve a lush, green lawn.

Cool Season Lawns

Cool-season grass types, such as tall fescue, Kentucky bluegrass, and perennial ryegrass, grow best when planted in the fall or spring. The best time to reseed a lawn with cool-season grass seed is in the early fall, between mid-August to early October, and at least 45 days before the first fall frost. 

If you have cool-season grass, it is imperative that you begin your reseeding project in early fall so that you have enough time to kill the lawn first, then wait at least two weeks (depending on the active ingredient) after applying the herbicide to seed.

Prior to reseeding, use an herbicide with an active ingredient such as glyphosate to kill your lawn. This type of herbicide is best absorbed during the active growing period for cool-season grass, which is in spring and fall.

It’s important to note glyphosate is a broad-spectrum herbicide, meaning it will kill any plant it touches. Practice caution before applying and read the product label. Most herbicides require waiting a period of at least two weeks post-application to apply new seeds. This waiting period ensures that the weed control is no longer active in your lawn and your new seedlings will be able to germinate.

Apply early in the morning and preferably when temperatures are between 65 – 85°F. Make sure you don’t apply on a windy day to avoid product drifting to nearby plants. 

If you miss the window to reseed in early fall, the second-best time is early spring, between mid-March to early May before the weather gets too hot. Reseeding cool-season grass in weather that is too hot or too cold can inhibit the growth of young grass seedlings. In order for grass seedlings to germinate, soil temperatures need to be at least 60°F.

If you reseed during the summer, the heat causes stress to grass seedlings and makes it difficult for them to grow. Reseeding in winter presents even more challenges, as there is less rainfall and both air and soil temperatures are too cold for seed to germinate and survive. 


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Warm Season Lawns

Warm-season grasses, such as St. Augustine, bermudagrass, and zoysia, have a higher tolerance for warmer air temperatures and require more sunlight than cool-season grasses. 

The best time to reseed a lawn with warm-season grass is spring when soil temperatures are above 65°F.

Why Early Fall is the Best Time to Reseed

Not only does early fall have the best weather conditions, and soil temperatures, but it also allows you enough time to kill your existing grass and reseed your lawn before the first frost arrives. Typically in early fall, the air temperature is cool enough that the seedlings won’t dry out and warm enough that conditions are right for seedlings to germinate. Reseeding in fall also gives the grass time to grow and establish a deep root system before the hot summer months.

The Bottom Line

Without a doubt, early fall is the best time to reseed a cool-season lawn. If you reseed in temperatures thatare too hot or too cold, the grass seedlings won’t germinate, and all of your hard work will go to waste! Knowing the right time to reseed will ensure you only need to do this process once. 

The sooner you reseed your lawn, the sooner you can have the lawn of your dreams! 

Once you make the decision to reseed and give your lawn the best treatment possible, the end result will be a revitalized lawn full of stronger, healthier grass. 

For more tips, articles, and videos on planting grass seed, visit our Lawn Care page!

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