How to Plant Grass Seed in Summer

How to Plant Grass Seed in Summer

It would be irresponsible to start an article like this without acknowledging that summer is one of the worst times of year to plant most types of grass. Just as cold weather can keep grass seeds dormant and prevent them from germinating, hot weather is like trial by fire for your young seedlings. But if you’re determined to establish a lawn from seed in the dog days, I’ll explain how to plant grass seed in summer in today’s article, focusing on tips that will help you succeed where many will fail.

Let’s dive in.

If Not Summer, When?

Spring and early fall are the best times of year to spread grass seed and successfully establish a new lawn, so if you’re considering throwing down some seed in late summer, maybe wait a few weeks to improve your results.

This is especially true for cool-season grasses. The ground better retains moisture in the fall and spring, and there’s more of it so you can cut down on your water usage.

Morning dew or moisture from rainfall can be quickly dried up by the sun during the dog days of summer, but they linger a bit longer to support young grass in the spring and fall.

Planting Grass Seed in Summer

But if you have the time and resources to water your lawn religiously, you can start a lawn from seed at any time of year.

And some types of grass are quite resilient to the heat and can be established effectively during the summer.

There are also measures that you can take while cultivating your yard to ensure the best chances of success, even when you’re fighting an uphill battle in the heat of summer.

Why Summer Is a Tough Time to Establish a Lawn

Summer offers even the most determined homeowners challenging conditions for growing grass from seed — or even laying sod.

Heat and humidity are not conducive for germination of most grass seeds or the long-term survival of many types of grass.

Certain breeds of grass seeds will not germinate in certain temperatures. Either because it’s too hot or too cold.

Even if your seed does manage to germinate and sprout, it is unlikely that young seedlings will survive long-term without the right conditions (and maintaining those conditions in the brutal heat of July and August requires a lot of work).

Water Needs

Grass seeds also need just the right amount of water.

Grass Seedlings - Grass Sprouting

If it has been a stormy summer, then waterlogged soil will pose a challenge. If the season has been very dry, then the grass seeds will not have enough moisture to sprout – especially once the afternoon heat hits and bakes the soil’s surface to a crispy crust.

Different breeds of grass seed also have different needs for moisture. Some are tolerant of dry weather, while others can survive (and thrive) in a monsoon.

The Threat of Weeds

A sparse lawn is an ample opportunity for weeds to move in, and aggressive annual weed seeds are floating on every gust of summer breeze. Creating a moist and fertile environment for your new grass will also create the perfect environment for aggressive weeds to take root in your yard.

Weeds will compete with grass for resources and make it difficult to get a new lawn established. If your soil is dense, dry or dusty, and compacted, then the soil won’t have enough oxygen to support growth.

Growing Grass from Seed in Summer Can Be Challenging Due to Competition from Weeds

If your new lawn germinates and begins to grow, it could quickly be smothered and overtaken by these more aggressive, hardier weeds.

Summer Sun – Friend or Foe?

Summertime also tends to be intensely sunny without many clouds to shield your lawn. This increase in sunlight (and heat) can be another important challenge for consideration.

If your lawn is totally exposed without any trees or bushes that provide shade, then it’s vital to find a type of grass that thrives in full sun.

And even then, if you don’t provide extra water, that hot sun will bake the soil and young seedlings with shallow roots can wilt in a single day.

Giving it Your Best Shot

If you do need to plant grass seed over the summer for one reason or another, there are some things that you can do to overcome some of the environmental challenges that the season poses.

Young Grass Seedlings in Summer After Germination

These are the methods I recommend and my best tips to help you learn how to plant grass seed in summer and establish a nice lawn during a tough time of year.

Choose the Right Type of Grass

Not all grass types are suited to all environments, and quality grass seed is expensive. Before you buy, spend a week and be observant about the space you are planning to establish a lawn.

It’s important things to consider these factors when selecting what grass seed to plant.

  • Is your lawn exposed to a lot of sun?
  • Do parts (or does all) of your lawn get light or heavy shade?
  • Do you live in a spot where you get rain or is it very dry?

It’s also important to consider your soil type – is it sandy or heavy clay?

Aeration Before Seeding Can Help

If your yard is barren, or if your lot has a lot of clay, your soil may be compacted. Compacted soil limits the important flow of oxygen and nutrients necessary for young grass roots.

Aerating the lawn area before spreading your seed or tilling the soil to loosen things up can help create ideal conditions for young grass and improve your germination rate with better water penetration, seed to soil contact, and improved airflow.

Rototiller
Using a rototiller to loosen compacted soil prior to seeding

That said, tilling your lot before seeding may bring up long dormant weed seeds to the surface. You may want to do this in advance of planting grass seed so that you can manage any weeds that come up.

No Competition – Weed Control When Starting a Lawn from Seed

Without grass to compete for resources and crowd them out, weeds will always run rampant in your yard. This may include dandelions, crabgrass, and more.

Remove weeds from your yard prior to establishing a new lawn from seed, and accept that you’ll have to do some weed mitigation after your lawn takes hold as well.

You want your new grass to thrive without having to compete for important resources such as water, oxygen, and sunlight.

If you’re killing your lawn and starting over, use a starter fertilizer with pre-emergent (like this one on Amazon, which I’ve used and recommend) to help your lawn take off while preventing crabgrass from germinating.

Cover Seed with a Fertile Mulch

The intense summertime sun can harm your young grass by drying it out. Mulching grass seed helps retain moisture without blocking airflow to the roots. It can also keep hungry birds from devouring your expensive seed.

Grass Seed on a Layer of Compost
Grass seed on a bed of rich compost before it is worked into the soil

You can do this by laying a protective layer over the seeds. Do this by leaving:

  • Wheat straw (avoid hay, it may contain weed seeds)
  • A grass mat
  • 1/4″ layer of screened compost
  • Commercial mulch for grass seed

Using your lawn mower to leave grass clippings on your yard after mowing will also help with this, but I recommend bagging your lawn clippings the first few times you mow a new lawn grown from seeds.

Fertilizing New Grass

Nitrogen and phosphorus are important elements for fertilizing grass seedlings. The Nitrogen helps with green growth and phosphorus is good for supporting healthy root systems.

When you shop for a fertilizer for grass grown from seed, pay attention to the three numbers on the bag.

Screened compost is my go-to top-dressing over seed and can help you build excellent soil to support your lawn long-term. In the summer it’s especially helpful because it’s nutrient rich and retains moisture.

Is Sod a Better Choice in the Summer?

Laying sod in the summer can be tricky. However, if you can afford it, establishing a lawn from sod instead of seed may give you better results as long as you keep up with watering.

When Is Sod a Better Choice Than Seed in Summer

Sod can certainly be far more costly than spreading grass seed, but you probably won’t have as many weeds to address at the end of the project, and the results will be nearly instantaneous.

Choosing Seed That Can Germinate & Thrive in Summer Heat

Some types of grass seed are more resilient in high-temperature weather. Having a good understanding of these grass types is important when learning how to plant grass seed in the summer.

If you live in a warmer, southern climate, these are some examples of excellent options for establishing a lawn from seed during summer weather.

A local landscaper or garden center will know the area where you live and your micro-climate. They are always a great resource and will be able to provide further guidance on grasses that thrive in your locality.

Bermuda Grass

Bermuda grass is commonly found in the southern part of the United States and has high heat and drought tolerances.

Bermuda Grass Lawn

This grass can withstand the particularly dry summer weather. It goes a step further and has a relatively moderate tolerance for cooler temperatures. This makes Bermuda a popular choice if your area has cool evenings, or if you are living further north in the transitional zone where the temperatures can fluctuate.

Bermuda grass is a resilient, full sun grass, though it may require a bit more maintenance, depending on your area. Its high wear-tolerance makes it a great option for high traffic spots that are completely exposed to the sun. It’s popular on golf courses for this reason.

Bahia Grass

Bahia grass is another breed of grass seed that’s popular for southern lawns. It offers high heat and drought tolerance and is pretty easy to establish in the summer.

Bahia Grass Lawn

Bahia requires less maintenance than Bermuda grass, but it’s also less resilient to wear and doesn’t hold up as well when walked over.

It works well in partially shady areas that still get a fair amount of sun.

Centipede Grass

Though the name may conjure unpleasant images, centipede grass is a favorite in the south due to its resilience and low maintenance requirements.

Centipede Grass Lawn (close up)

Centipede grass can withstand high heat, but it is less resistant to drought. That said, it’s incredibly well suited to the hot, humid areas of the Southeastern United States.

Centipede grass is also a good option if you don’t mind regularly watering the lawn. It has a lower tolerance of cool temperatures than the other warm-season grasses, but it has higher shade tolerance than most.

Zoysia Grass

Zoysia grass sounds quite exotic, and thus high maintenance, but nothing could be further from the truth.

Close Up of Zoysia Grass Lawn

This popular type of grass is highly adaptable to a range of environmental conditions. It can withstand high heat, cooler weather, drought, high traffic, and both shady or sunny conditions.

Pair this versatility with the fact that Zoysia has only moderate maintenance requirements, and it’s easy to see why it’s one of the most versatile breeds for seeding in the summer.

Choose the Right Seed For Your Climate

Whatever grass you choose, it’s important that you choose something that will thrive long-term in your climate, not simply in the summer.

If you live in a northern climate, you’ll need to go with a cool season grass seed, or a blend of different cool season grasses.

If you live in the south, you’ll want something tailored to the heat and conditions where you live.

Lawn Enforcement

It’s not impossible to grow grass from seed in the summer months, but tackling this project will require a bit more effort and maintenance compared to establishing a new lawn in late spring or early fall when conditions are more ideal.

How to Plant Grass Seed in Summer Successfully

There are some measures that you can take to overcome some of the challenges that accompany hot weather seeding. Hopefully, the advice shared in this summer seeding guide will have you admiring a carpet of green grass by fall.

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Grass Seed Calculator - small screenshot

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Sarah’s blog, Lawn Chick, is read by over 2 million homeowners each year and she is regularly cited as an expert source of lawn care knowledge by major publications. Her goal is to meet you where you are, and help you achieve a yard you’ll be proud of. Ready to take the next step toward improving your lawn? Grab her free lawn care cheat-sheet: What to Do When - Take the Guesswork Out of Lawn Care, or upgrade your garage by browsing her favorite DIY lawn care products.

2 thoughts on “How to Plant Grass Seed in Summer

  1. Herb Garcia

    Hi Sarah
    I live in Southern Connecticut – near NY state line. On Sept 2, 2021, My lawn maintenance company did Core Aeration and over-seeding using Turf type Tall Fescue blends on my lawn which had some brown spots which had no grass due to hot summer sun in August. Prior to them over-seeding I did some thatching, and yanked out weeds, and checked PH in soil and added what I needed. I bought an oscillating sprinkler and a water timer so I can water the new seeds at least 3 times a day (morning, afternoon, and evening).

    Today is now Sept 14 2021 and I can see the seeds have germinated and started growing about 1 inch. The established part of my lawn is also growing and soon needs to be mowed but I know I have to wait for new seed to grow a little more even though its 85% Turf Tall Fescue and I think most (if not all) appears to have germinated already.

    My problem is this. The Brown spots have some new seed germinating but not enough to fill in the entire brown spot. Even after the grass grows more, I think it will still be thin and not fully covered. So my question if this: Should I add more seed to those thin brown spots knowing that I will have to wait another 3-4 weeks before I can mow (my established lawn is in need of mowing soon due to amount of 3x watering I am doing daily), – or should I wait for this new seed to grow to point where I can mow the lawn, then mow the lawn, and then lay down more seed to fill in those bare spots ?
    I am also concerned and watching the weather. Daytime temps are around 79-84 and night time temps are 65-70F but that will all change in about 1 week when daytime temps drop around 70-75F and night time temps 63F-55F. So if I wait to re-seed, I am scared it might get too cold for new seed to grow?

    What do you think I should do?
    Thanks
    Herb G

    • Hey, Herb!

      Sorry for the late reply to your comment, I was swamped this fall! Anyway, I wanted to be sure to answer your comment in the event that it still helps you, or it helps someone else with the same question.

      My advice would be to spot-seed those thin areas after you do the first mow and bag the clippings. Alternatively, you could just go after those areas with a rake to loosen the soil and re-seed them right away as if you were starting a new lawn, and avoid them when mowing the rest of the lawn to let the new seed germinate and catch up.

      And I wouldn’t worry about the temperatures you describe here. If you’re seeding in the spring, your soil will typically be too cold for good germination even once air temperatures are warm enough because the soil warms up a little slower. In the fall, your soil will remain warm enough for germination even as air temperatures start to dip. That’s one of the reasons why fall is such a good time to seed in northern climates – the air temperatures are cool, there’s more rainfall and moisture, but soil remains warm from the summer heat. Usually, you can have good results with cool season grass seed in the fall even if it feels like it’s too late to throw down seed. Unless you’re close to a frost, you’re probably still ok.

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