This Is the Best Time to Plant Grass Seed, According to Lawn Experts

If you want lush green grass, timing is everything. Freshly planted grass seed needs adequate water, sunlight, and soil conditions to thrive. Because sunlight and soil temperature change throughout the year, there is a narrow window of time you have to plant grass seed to ensure it flourishes. To help you get it right, we tapped lawn experts who share their tips for when (and when not) to sow grass seed.

When to Plant Grass Seed

When you plant grass seed depends largely on where you live and the type of grass you have—cool season or warm season.

Cool Season Grasses

Late summer to early fall–when temperatures are around 70 to 75 degrees Fahrenheit—is the best time to plant new cool-season grasses, like Kentucky bluegrass, tall fescue, ryegrass, and fine fescue. "This period historically includes a higher chance of rainfall, which will help keep the soil moist, aid in seed germination, and provide enough daylight to ensure the grass thrives in enough time to out-compete weeds and survive a cold winter," says Roger May, director of technical operations for TruGreen.

Warm Season Grasses

Warm season grasses (Bermuda, zoysia, centipede, St. Augustine, etc.) are typically not over-seeded but established using sprigs, plugs, or sod, says May. That said, these grasses are typically grown during summer months when temperatures are above 80 degrees Fahrenheit. "Even in these perfect conditions, germination rates are typically lower when warm-season grass seed is utilized," says May.

Best Time to Plant Grass Seed by Season

Keep these seed-sowing windows in mind for each season when planting grass seed.

• Spring: March to April is the best time to plant in spring for most areas. If you have to plant in the spring, do it on the early side to give your new grass the best chance of maturing before the summer heat, says Craig Elworthy, founder of Lawnbright.
• Summer: Late August to early September is the best time to plant new seed during summer, says Elworthy. Avoid sowing in June, July, and early August, which is when weed pressure is very high, temperatures are too hot, and the water required to get your new seed to germinate can create fungal issues, he says.
• Fall: September is the ideal time to seed during fall as soil temperatures are still warm enough to allow for seed germination and ideal for the new seedlings to become established, says May.
• Winter: Cool-season grasses can be sown during winter—a process called dormant seeding. This method works best when grass seed is covered with several inches of snow after seeding that remains over the entire winter.

Tips for Planting Grass Seed

Keep these expert tips in mind when planting grass seed.

• Prepare the seed bed: If you’re spreading seed on bare ground, make sure to till the ground to a depth of 2 to 3 inches first, and consider adding a quality loam or compost mix before seeding, says Elworthy.
• Dethatch: Thatch is a layer of dead grass and root material that sits between healthy turf and the soil. Dethatching your lawn before seeding will boost germination rates and help your lawn grow quickly, says Elworthy.
• Choose high-quality seed: Choosing a high-quality seed suitable to your climate and growing conditions will save you money and time in the long run. A blended mixture of several different types of grass can help lawns with varying conditions and sun exposure, says May.

What to Do After Planting Grass Seed

Adequate care after planting grass seed is essential to ensure it germinates and grows.

• Keep seeded area moist: Keep the topmost layer of the soil wet for the first two weeks, says Elworthy, adding that the water should not pool on the surface, and it shouldn’t dry out for any stretch of time.
• Tamp down seeds: After sowing, tamp down the seeded area either with your foot or a lawn roller to ensure adequate seed-to-soil contact.
• Add organic material: Cover the seeds with a thin layer of peat moss or other organic content. "This will help keep the birds from ruining your seeding project," says Elworthy.
• Add liquid fertilizer: Fertilizing when seeding isn't necessary. Grass seed already contains everything it needs to germinate, says Elworthy. Instead, wait until your new grass has germinated, then use a liquid starter fertilizer.