When is The Best Time to Plant Grass Seed in The Fall?

As winter arrives in cooler areas of the country, many plants die or go dormant. Other plants thrive in colder months, including evergreens and even some grasses, so it’s an option to lay a new bed of grass for winter coverage.

Early fall is the best time to plant cool-season grass seeds because they’ll germinate through the autumn months and sprout before winter. Be sure to plant them before the first cold snap since frost can kill off the root system or seedlings before the grass has established itself. 

What Month Is Best to Put Grass Seed Down?

What Month Is Best to Put Grass Seed Down

Although it will vary by location, mid-September is the best time to seed your lawn in the Northeast or the Midwest, where daytime temperatures normally settle into the 60s and 50s by October. Aiming to have the grass established 45 days, or about 6 weeks, before the first frost will give time for germination and growth to a healthy mature state.

Growing rates will differ by the type of grass, though, so the general rule of 3 weeks for germination, 3 weeks for growth may be more accurate for some types of grass than others. 

Waiting until too late in the fall to plant grass seed might push the limits of the seasonal change, so thinking ahead about the growth period and the process will keep you on schedule.

Grass seeds and seedlings will need lots of water throughout the growing period, and moist soil will retain heat even when temperatures lower overnight. Keeping the soil moist might help extend your fall growing period, although it’s not guaranteed.

Planting Grass Seed

Preparing the lawn to accept grass seeds is an important first step towards getting good winter coverage. There are a few options when sowing grass seeds:

Planting Grass Seed
  • Overseeding the existing lawn – when you spread grass seed over your current lawn, it has to be timed with when your warm-season grass goes dormant since the new grass will need nutrients and sunlight without competition. Aerating your lawn and raking up any thatch will let the seeds get down into the soil, and you can just sprinkle the grass seed on the lawn this way. 
  • Tilling and mulching existing lawn – if you want to completely replace the summer lawn with a winter one, you can till over the yard and mulch the grass and roots into the soil, then distribute the seeds. This is a more intensive and less attractive option, but it will fertilize your lawn for lush new growth.
  • Spot-seeding – sometimes you don’t need to replace the whole lawn, but some areas are thinner or patchier than others. In this case, you can either aerate, rake, and seed specific areas or till those patches and plant the new grass. Either way, when you spot-seed, you can keep most of your lawn intact while attending to spaces that need it.  

Types of Cool-Weather Grass

Across the temperate northern states, Kentucky Bluegrass is the most popular cool-season grass. It has dense coverage with a dark green color and extends its roots across the yard to fill in all spaces. While this grass has some tolerance to both warm and cold temperatures, it’s the main choice for cool-season lawn coverage.

Fescue is another popular type of grass, with many species that have high cold and shade tolerances. This long, thin bladed grass is a popular choice in cooler climates for its durability and interesting wave patterns that develop when it grows out.

Rye grasses have high tolerance for cool weather and are quick to grow and establish over the yard. This lower-maintenance type of grass is preferred for its fine blades, dense growth, and easy sowing that requires less soil preparation than other grass species. 

Mixed Bags of Grass Seed

Mixed Bags of Grass Seed

Grass seed packages are often a mix of different types of grass seed. This helps increase the chances that a particular species will grow while others will fill in for full coverage. Sometimes, this means shade-tolerant seeds will dominate shady areas, while more sun-tolerant grasses will fill in sun soaked parts of the lawn.

Some kinds of seeds are also more fungus or disease resistant than others, which can help the soil’s overall health across your yard. When you buy grass seed, the package should list the types of grasses and their strengths included.