When Is It Too Late To Plant Grass Seed? (Spring or Fall) | Turf Mechanic (2022)

To achieve the best possible lawn come spring, it typically means you need to overseed the preceding fall to fill in bare spots and thicken sparse areas. When it comes to timing this project, the most important thing is to keep in mind is not sowing seed too late.

When determining when it’s too late to plant grass seed, you first need to figure out the right time to sow grass seeds.

Generally speaking, most people overseed or seed a new lawn in September because the blistering summer heat is in the rearview mirror, and the frozen ground of winter is still months away.

In many cases, though, a later autumn seeding may make more sense. And in some instances, seeding shouldn’t happen in the fall at all, but in the spring.

What You Should Know About The Timing of Sowing Grass Seeds

Experts have extensively tested the best time to sow grass seeds at the National Turfgrass Evaluation Program (NFEP), and they have discovered the following.

  • The timing cannot be generalized because there are several kinds of grasses used for lawns, and these different types are better suited for different climates based on how they grow. In turn, different planting times are ideal based on the grass type.
  • For the sake of convenience, they can be divided into two broad kinds: warm-season grasses and cold-season grasses. As you may have guessed, warm-season grasses grow the most during summer and cold-season grasses during the cooler spring and fall.

Because the two different types produce the majority of their biomass at different times during the growing season, it’s reasonable you should sow grass seed at different times.

In general:

  • Warm-season grasses should be planted in the spring.
  • Cool-season grasses should be planted in the fall.

The goal with putting down seed is to time it just before the natural period of its most active growth (depending on the type of grass seed you’re using). By doing this, new sprouts grow fast and have a great start on establishing before they go dormant in the late fall.

Always time planting in regards to the seed type, and not the climate you live in. For instance, if you are overseeding a warm-season lawn with cool-season grass, always do it in the fall.

What happens if you plant your grass seed too early?

Grass seed planted too early will struggle with germination and early growth.

  • If you plant warm-season grasses too early in the spring, the air and soil temps will be too cool (and possibly) wet for germination. The seeds can either die off, or if they do germinate, young seedlings are at higher risk for damping-off.
  • If you plant cool-season grasses too early in the late summer or early fall, the temperatures will be too high, and seedling growth will slow or halt. Seedlings may also suffer from too little water in hot conditions.

Also, keep in mind that when plants are stressed from environmental conditions, they are more susceptible to insect pests and disease problems.

What happens if you plant your grass seed too late?

If you plant your grass seed too late in the season, you’ll shorten its period of “good” growth. The root system will not have had the time to work its way down into the soil well. The grass blades will not have had time to adequately establish themselves and harden for the upcoming winter conditions.

(Video) When Is It Too Late To Put Grass Seed Down? Sowing Seed In October?

When the air and soil temperatures begin to drop in the fall, these plants are less equipped to handle dormancy than seeds planted earlier. Because of this, you will likely see an increase in winterkill, with fewer plants surviving to spring.

Optimal Temperatures to Plant Grass Seed

Timing is dependent upon temperature since this influences germination the most.

  • Warm-season grass seeds germinate best when soil temperatures are 65-70°F or daytime air temperatures are above 80°F.
  • Cool-season grass seeds germinate best when soil temperatures are 50-60°F or daytime air temperatures are 60-75°F.

Best Time to Plant Grass Seed By Turf-Growing Region

The right time to plant is just before the preferred season of growth arrives. If you time it correctly, you will find that most seeds will germinate and grow into healthy grass within their growing season!

Naturally, it would be best if you treated any time after this ideal point as too late to plant your grass seeds.

However, being a little late is still permissible and may work out okay if your seeds get favorable weather. On the other hand, it is entirely too late when your seed is trying to grow in adverse weather conditions.

A general guideline is to plant cool-season grasses 45 days before the first fall frost is predicted and plant warm-season grasses 90 days before the first fall frost.

The turf-growing region you’re in relates directly to the type of grass you should be planting.

What are the turf-growing regions?

The US is divided into five different turf-growing regions based on annual temperature differences and humidity levels.

  1. The cool, humid Midwest, Northeast, and Pacific Northwest coast.
  2. The cool, arid area spanning across the Intermountain West and the majority of the Great Plains.
  3. The warm, humid area in the Southeast.
  4. The warm, arid area in the Southwest.
  5. The transition zone overlapping the cool and warm regions.

“Cool” zones grow cool-season grasses, “warm” zones grow warm-season grasses, and the transition zone grows a combination of both cool-season and warm-season grasses.

When to Plant Grass Seed in Each Growing Region

The best month to put grass seed down depends on the type of grass you are growing.

  • Cool-season grasses are typically planted in Northern areas in mid-August to mid-September. In the transition zone, plant mid-September to early or mid-October.
  • Warm-season grasses are typically planted in Southern areas in April or May and May to June in the transition zone.

Region
Grass Type
Planting Date
Air Temp
Soil Temp
Cool Humid

Midwest & Northeast
Cool-Season
Mid-August to Mid-September
60-75°F
50-60°F
Pacific Northwest
Cool-Season
September to Mid-October
60-75°F
50-60°F
Cool Arid
Cool-Season
Mid-August to Mid-September
60-75°F
50-60°F
Warm Humid
Warm-Season
April to May
>80°F
65-70°F

(Video) When Is it Too Late to Plant Grass Seed?

Cool-Season
October to November
60-75°F
50-60°F
Warm Arid
Warm-Season
April to May
>80°F
65-70°F

Cool-Season
October
60-75°F
50-60°F
Transition Zone
Cool-Season
Mid-September to Mid-October
60-75°F
50-60°F
Warm-Season
May to June
>80°F
65-70°F

Midwest: Northern Illinois, Northern Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Northern Ohio, South Dakota, Wisconsin

Northeast: Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont

Pacific Northwest: Oregon, Washington, Far Northern California, Southeastern Alaska, Northern Idaho

Cool Arid: Colorado, Idaho, Montana, Nevada, Utah, Wyoming

Warm Humid: Alabama, Florida, Georgia, Mississippi, South Carolina, Southern Texas

Warm Arid: Southern Arizona, Southern New Mexico, Southern Texas

Transition Zone: Arkansas, Southeast Colorado, Delaware, Southern Illinois, Southern Indiana, Kentucky, Maryland, Southern Ohio, Oklahoma, North Carolina, Tennessee, Virginia, West Virginia

Related FAQs

Q. Is it too cold to plant grass seed at 40°F?
Yes, it is too cold for grass seed to germinate at 40°F.

Q. Can you plant grass seed in 90°F weather?
Cool-season grasses will not germinate in 90°F weather; they prefer air temperatures between 60-75°F. Warm-season grasses may germinate at 90°F but typically don’t grow when air temperatures are above 90-95°F.

Q. Will grass grow in 45°F weather?
Warm-season grasses (typically grown in warmer, Southern climates) will not grow in 45°F weather. They don’t become active until soil temperatures hit the mid-50s. Some cool-season grasses start growing when air temperatures are 40-42°F, but most prefer slightly warmer temps.

(Video) When Should You Stop Watering New Grass Seed?

Q. Can I plant grass seed in 50°F weather?
Yes, you can plant in 50°F weather, especially if you are sowing cool-season grasses. They germinate best when daytime air temperatures are 60-75°F. Warm-season grasses germinate best when daytime air temps are above 80°F.

Q. How late in the fall can you plant grass seed?
Warm-season grasses go dormant when temperatures drop below 55°F. Cool-season grasses go dormant when temperatures dip below 40-42°F. If your local temperatures are above these thresholds, you can plant, but results may be lackluster.

Q. Can you put down grass seed in the winter?
Yes, you can sow seed in the winter. Putting seed down in the winter months is known as dormant seeding. Once the weather warms up in the spring, seeds will begin germinating.

Q. When is it too late to plant grass seed in the spring?
Ideally, you shouldn’t plant cool-season grasses once the soil temperature is above 60°F. Their growth slows considerably and may halt once air temperatures get too hot. If you are planting warm-season grasses, it really isn’t possible to plant seeds too late in the spring.

Last Parting Thoughts

So, the often asked, “when is it too late to plant grass seed” isn’t something you can answer with a quick or standard reply. Theoretically, grass seed can be planted as long as the air and soil are warm enough—yet not so hot—the grass type isn’t triggered to go into dormancy.

That being said…you want to plant just as the grass goes into the season where it grows the best, giving it maximum time to establish before winter dormancy. Therefore, it’s too late to plant grasses when you miss this growth window.

  • Cool-season grass varieties should be planted in the fall once soil temperatures drop to 50-60°F. Once soil temperatures drop into the 40s, it’s too late to plant cool-season grasses, as the seed doesn’t have enough time to germinate, and seedlings establish before going dormant for the winter.
  • Warm-season grass varieties should be planted in the spring when soil temperatures reach 65-70°F. Once the air temperature gets above 90-95°F, it’s too late to plant warm-season grasses as the heat causes growth to slow or halt, and seedlings can’t establish well before temps drop in the late fall.

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If you want to have the best possible lawn in the Spring then that usually means you have to put down some extra grass seed in the fall but knowing when it’s too late to sow grass seed in your climate is one of the most important things to consider when it comes to timing.

Generally speaking most people overseed or seed a new lawn in the month of September because the highest heat of summer is in the rear view mirror while the frozen ground of winter is still months away but in many cases a later autumn seeding may make sense. Let’s look at the variables that should go into your decision to put grass seed down later in the year.

Cool season grass seed will germinate in soil that is at least 45 to 50 degrees and it will grow vigorously in soil temps between 50 and 65 degrees. Outside air temperatures can be much lower than this without affecting the grass so long as there is no frost. Frost or freezing temperatures can kill new grass seedlings if their root structure isn’t well established.

For people who choose to sow grass seed late in the Fall you have to check soil temps to make sure they are above 45 degrees and you will need to prepare the soil well to ensure the quickest germination speed and consistency possible for the seed you lay down.

To keep sprouts alive as temperatures dip in late October and November you will want to fertilize your new grass with both starter fertilizer to establish root growth and potassium to quickly build up the new grass’ ability to overcome stresses like cold weather, frozen soil, and snow compaction.

(Video) When's The Best Time To Seed The Lawn? Planting Grass Seed with Allyn Hane The Lawn Carew Nut

If early frosts and freezing temperatures are in the forecast then covering your sprouts with garden fabric or greenhouse plastic may be necessary to keep the grass warm and growing as late into the year as possible.

There’s still a lot to say about this topic though so let’s start with a video I created specifically to address this topic before we go into further detail.

If you have decided to grow grass from seed this season then the following articles on this site will probably be helpful either now or in a week or two when you get to that part of the process:

When To Mow New Grass From Seed
How Long Does Grass Take To Fully Grow
What Does Potassium Do For Grass

However, you can learn more about the germination rates of grass when spread on top of the soil on our article entitled Will Grass Seed Germinate on Top of Soil?

Click here to find out how you can deter birds from eating your grass seeds.

Please click here to find out the best time to plant grass seed.

Expert recommend not growing the grass seed in adverse weather conditions because it actually makes it harder for the grass seed to grow in a healthy way. The growth of the young seed at this stage is actually what is going to decide the overall look and strength of your turf, and you don’t want to get it damaged by planting your seeds too late, do you?

See my full grass growing guide here for more helpful tips – no opt-in needed.

How much grass seed do you need per square foot?

Now, figuring out the answer to this question is not too easy- you have to actually take all the above mentioned things into account. For example, if you use the right grass for a warm climate, and plant it at the right moment in a sunny spot, you might actually have to use very little seed!

You know what goes well with artificial turfs? Trampolines! A lot of people are afraid of using sprinklers with trampolines, and if you’re one of them, click here to read our article on Do Sprinklers Ruin Trampolines?

(Video) 6 Beginner Mistakes to AVOID When Sowing Grass Seed

FAQs

How late can I sow grass seed? ›

You can generally sow lawn seed and grass seed mixtures between March and October as long as the seedbed is kept moist during dry spells, but this season is extended when weather conditions are favourable.

What month is best to put grass seed down? ›

Plant cool-season grass seed in late summer or early fall (when daytime temperatures lower to about 60 to 75 degrees) for best success. September is typically the best month, although you might be able to get away with seeding as early as mid-August or as late as mid-October; it all depends on the forecast.

What temp kills grass seed? ›

New Grass In Warmer Temperatures

Damages from heat and humidity affect the grass seed's growth. Temperatures above 100 degrees Fahrenheit are strong enough to harm them. Under 140 degrees Fahrenheit or hotter can kill them within a short period of exposure.

Can I just throw grass seed down on existing lawn? ›

By spreading grass seed over your existing lawn, you can thicken up the thin areas, and your lawn will start to look terrific again. (This is different from reseeding, which is when you start over and plant a completely new lawn.)

Is it better to seed grass before or after rain? ›

In general, it is best to sow grass seed before it rains, as is easier to work dry soil and rake the grass seed into it. Mulching can help keep the seed bed moist throughout the germination and early growth period. Sowing seed after it rains is not only a messy endeavor, but walking on mud can compact the soil.

Should I water grass seed morning or night? ›

The best time to water grass seed is in the morning and evening. These are the coolest parts of the day, which allows water to absorb into the ground instead of evaporating.

How do you seed a lawn that already has grass? ›

Do-it-Yourself: Lawn Overseeding - YouTube

Can new grass seed survive a frost? ›

The easy answer is that frost will not kill grass seed, but that does not mean that you should plant grass seeds when there is danger of frost. While the seeds will survive until the next growing season, any seeds that sprout into seedlings will not.

Does grass grow in 40 degree weather? ›

Will Grass Grow in 40 Degree Weather? Although some mature cool-season grasses will not enter full dormancy until soil temperatures reach 40℉ (4℃), growth will slow to almost a complete stop by this point. Cool-season grass seed cast in 40-degree weather likely won't sprout.

Should I water grass seed if its going to freeze? ›

Watch the weather ahead of time to see if there are any chances for an early freeze. It is best to water the grass the day before a freeze because the wet soil acts as insulation to the grassroots. Roots are more likely to freeze if the ground is too dry. Stop watering when the ground freezes.

What happens if you put too much grass seed down? ›

All plants, including grass plants, need adequate soil space for roots to spread and develop. If you put down too much grass seed, you will encourage competition that will cause your grass seedlings to struggle after germination because there will be excessive competition for sunlight, soil nutrients, and water.

What happens if you put grass seed over weeds? ›

Spreading grass seed on a weedy lawn won't do much good. Weeds that are actively growing in your grass will steal water and nutrients from grass seedlings, causing them to struggle and die. For best results, attack lawn weeds with a weed killer, then overseed to create a healthy lawn that prevents weeds from returning.

Will grass seed grow on top of dirt? ›

But, will grass seeds germinate on top of soil? As a general rule, grass seeds will still attempt to grow on top of the soil; however, you will get poor results compared to grass seed covered with 1/4 inch soil. Uncovered grass seed is likely to dry out, be eaten by birds, or be carried away by water runoff.

Is November too late for grass seed? ›

While planting grass seed in November is too late to make the fall growing season, there is a method called dormant seeding. Through dormant seeding, grass seed can be planted in November when the weather is cold enough to keep it dormant until the weather warms up in the spring.

How late can you sow grass seed UK? ›

You can sow Lawn UK lawn seed mixtures at any time from late March to mid-October providing that in periods of unusually dry weather the seedbed is kept constantly moist until the grass is about 6cm (2.5 inches) high.

Can you sow grass seed in November? ›

It is now too late to sow grass seed, but new lawns can still be laid from turf if the weather is not too cold. Don't feed the lawn with left-over summer feeds. These contain too much nitrogen, which stimulates lush growth; at this time of year, lush growth will be vulnerable to diseases.

Can you overseed in October? ›

Overseeding is Better Late than Never

There will be plenty of time to fix most turf problems. Overseeding in October, or as Uncle calls it “OctOverseeding,” when the days are warm, nights are cool, and soil temperatures remain above 55°, allow grass seed to sprout very quickly.

Is it too late to plant grass seed in December? ›

Grass seed can survive the winter, and planting during the winter season is known as dormant seeding. If you put down grass seed in November or December, the seed will just lay dormant until the soil starts to warm in spring. While this comes with risks, it can also be beneficial and save you time on seeding in spring.

How long does it take for grass seed to germinate in October? ›

The seeds will take two to four weeks to sprout and during this time the ground should be kept damp. Proper watering one to two times a day is essential for a new lawn. This watering routine should be kept up until the grass sprouts are at least one inch tall.

Is dormant seeding better than spring seeding? ›

Some research has shown that dormant seedings will outperform spring seedings. This is particularly true with Kentucky bluegrass and to some extent, tall fescue. They have a couple more weeks to develop than spring seedlings, which can be critical for summer survival.

How long does grass seed take to grow in winter? ›

The soil is warm, there is plenty of moisture and the weather is neither too cold nor too hot. Germination should take between seven and 10 days and seedlings will become established before the first severe frosts in late autumn, this is the preferred time as the roots establish better through the winter.

Can I plant grass seed in 30 degree weather? ›

The Short Answer. Generally speaking, if the daytime temperature is cooler than 60°F, that means that your soil temperature will be lower than 50°F. In this case, it's probably too cold for you to plant grass seed. If there is still the possibility of frost outside, then it's definitely too cold to plant grass seed.

Will grass seed germinate on top of soil? ›

But, will grass seeds germinate on top of soil? As a general rule, grass seeds will still attempt to grow on top of the soil; however, you will get poor results compared to grass seed covered with 1/4 inch soil. Uncovered grass seed is likely to dry out, be eaten by birds, or be carried away by water runoff.

Can I plant grass seed if it freezes at night? ›

If temperatures reach freezing at night, do not spread grass seed. Warm days and cold nights are deadly conditions for grass seedlings. Track soil temperatures in your area to make sure they are well above freezing before you plant grass seed.

Does frost affect grass seed? ›

The easy answer is that frost will not kill grass seed, but that does not mean that you should plant grass seeds when there is danger of frost. While the seeds will survive until the next growing season, any seeds that sprout into seedlings will not.

What is a good winter grass seed? ›

There are two types of winter grass used: annual ryegrass (Lolium multiflorum) and perennial ryegrass (Lolium perenne). Both types adapt well to sun or shade situations. Annual ryegrass, which is sometimes called Italian ryegrass, is cheaper and dies out readily in late spring following an autumn planting.

Should I fertilize or overseed first? ›

Most landscaping professionals agree that it is always best to fertilize the soil first if you are seeding a new lawn. It is also recommended to conduct a soil test so that you select the appropriate fertilizer.

Should I pick up plugs after aerating? ›

– The Short Answer. The consensus is that no, you should not pick up plugs or cores after aerating. In a few days, these little pieces of your lawn should break down and become unnoticeable. This process is aided by watering your lawn deeply after aerating or waiting to aerate before it rains.

Will grass seed survive the winter? ›

Can Grass Seed Survive Winter? Yes, it often does. Spreading seed in late fall or early winter is called dormant seeding because it will not sprout until spring, especially if it's covered with snow.

Videos

1. There’s 0% Chance SEEDING a LAWN in Spring will Survive UNLESS you master 3 THINGS
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2. How to GROW GRASS in the SPRING successfully step by step
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3. Seeding Your Lawn This Spring?...Watch This First!!! | Spring Lawn Care Tips
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4. It is too late to seed your lawn?
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5. How to Fix a Grass Seed WASHOUT / Lawn Project Rain Damage / Fall Overseeding
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6. Will Grass Seed Germinate If It's Sitting Directly On Top Of The Soil?
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