How Long Does It Take for Grass Seed to Grow? Timeline, Care Tips, and More

Waiting for grass to grow is almost as fun as watching paint dry. So, how long does it take for grass seed to grow? From seed to germination to first sprouts, here’s everything you need to know about cultivating your future lawn.

Grass Growth Timeline 

In general, how long does it take to germinate grass seed? It can take anywhere from 7 to 21 days, but this varies based on the type of grass and the surrounding conditions. With proper care, your lawn could be full and ready to mow in one month. 

If you need help determining the best grass type for your lawn and growth timeline, hire a local lawn seeding service to advise you on the best course of action.

• Days 1 (seeding day) to 14 (germination observed): Water for 15 minutes four times per day.

• Days 15 to 21: Water 30 minutes one time each day.

• Days 22 to 28: Water 40 minutes one time on alternate days.

• Days 29 and beyond: Water 45 minutes three times per week, or enough to deliver 1½ inches of water per week (skip watering when you receive sufficient rainfall).

Warm- vs. Cool-Season Grass Seed Growth

It’s crucial to choose the right type of grass seed for your area’s climate, as different seed varieties are naturally suited to thrive at certain temperatures. You can choose between cool season vs. warm season grasses.

With that in mind, the type you choose also plays a big role in how long it takes grass to grow. Cool-season grasses generally germinate the quickest, while you’ll be waiting longer for warm-season grasses to sprout.

Warm-Season Grasses

Warm-season grasses can take anywhere from 7 to 30 days to germinate. 

If you’re planting these types of warm-season grasses, here’s when you can start expecting germination:

• Bahia grass: 28 days

• Bermuda grass: 7–14 days

• Centipede grass:  14 days

• St. Augustine grass: 7–14 days

• Zoysia grass: 14–21 days

Cool-Season Grasses 

Cool-season grasses can start germinating in as little as four days after planting, or after up to 21 days for Kentucky bluegrass. 

Here are your basic timelines for these types of cool-season grasses:

• Fine fescue: 4–8 days 

• Kentucky bluegrass: 14–21 days

• Perennial ryegrass: 5–7 days

• Tall fescue: 4–14 days

How Long It Takes Grass Seed to Grow: 4 Factors

Grass is a pretty finicky plant—while your bag of seed might name a specific timeline for germination and growth, you might find that your lawn deviates from the norm. That’s because many external factors play into your grass’ growth potential. 

Here are the biggest factors that determine how long it takes for grass seed to grow (and how well it does):

Type of Grass Seed

There are a wide variety of grass types, each with its own ideal growth conditions. There are warm-season and cool-season grasses, the former thriving in hotter climates, while the latter can’t stand high temperatures. 

That’s why it’s especially important to choose a native type of grass that thrives in your area’s climate—the wrong seeds will germinate and grow significantly slower, if at all. 

Germination

Different types of grass seed germinate at different rates, but even still, there’s a wide range of dates for average germination. For example, tall fescue grass can germinate in as little as four days, or it can take up to two weeks. 

Soil Conditions

Grass generally grows best in soil that’s well-aerated and rich in organic matter. Hardened, compacted soil without nutrients will not make a good host for healthy grass. 

Poor soil conditions will lead to slow (or absent) growth as well as patchiness and weak grass overall. Get a quote from a local lawn aeration company to improve your soil before seeding. 

Weather 

Even after choosing the proper type of grass for your area’s climate, your future lawn is still at the mercy of Mother Nature. Steady rainfall will keep your seeds happy and moist, while extreme storms and flooding might wash them away before they germinate. 

Dry spells and extreme sun in the afternoons will quickly evaporate moisture from the soil, which is bad news for new grass, as it’s extra important that it stays hydrated during its initial growth period. 

When to Plant Grass Seeds 

Your healthy lawn starts with timing your planting right. It’s best to plant cool-season grasses in spring when temperatures stay between 60 to 70 degrees Fahrenheit. You can also plant grass seed in the fall, but be sure the sprouts can get fully established well before your area’s first expected frost date.

As for warm-season grasses, you’ll want to plant these in mid-to-late spring or early summer, just as the weather is beginning to heat up. Aim for day temperatures of around 80 degrees Fahrenheit, and wait until all danger of frost has passed in your area. Keep in mind that the best time to reseed a lawn is late summer to early fall. 

Tips for Growing Grass Seed

Despite how commonly it’s cultivated, growing grass is tricky to master. Learning how to grow grass is a matter of timing, ensuring ideal soil conditions, and most importantly of all, keeping it adequately watered. 

Now that you know how long grass seed takes to grow, here’s how to give your lawn the best chance at growing thick and healthy:

• Water new seeds twice a day; ideally once before 10 a.m. and once at dusk.

• Spread grass seeds as evenly as possible (consider investing in a mechanical spreader for optimal results).

• Do not overwater your grass seeds: Aim to fully saturate the soil, but do not allow the area to pool or flood. 

• Spread a 1- to 2-inch-thick layer of compost over the soil before spreading seeds.

• Consider adding a thin layer of straw mulch on top of a freshly seeded lawn to help retain moisture, keep out birds, and prevent seeds from blowing away.

• Test your soil’s pH to determine your fertilization needs.

• When planting grass seed on hard dirt, aerate your soil beforehand and add fresh topsoil to trouble spots.

• Keep people and pets off your new lawn until it’s fully established. 

How Long Does Grass Take to Grow Back After Mowing?

After your first mowing, you can expect your new grass to grow about 0.8 inches per week, although favorable weather can see growth of 1 inch or more in a week. Again, the type of grass and its growth conditions will play a major role here. Most grasses will go dormant and stop growing altogether when temperatures become too hot or too cold. 

Mowing Your New Lawn

You’ll want to wait at least one month before mowing your new grass for the first time, or until your grass blades are 4 to 4½ inches long. After that, aim for a lawn length of around 2½ to 3 inches before mowing again. Note that it’s always best to research what works for your specific type of grass.

To ensure your lawn stays healthy and vibrant, never mow more than ⅓ of your grass height at once. Mowing too deep can impede its ability to retain nutrients and lead to a thin, weakened lawn over time. Hire a local lawn mowing company to help you keep your grass in tip-top shape if you need help maintaining a schedule.