What Is Spray On Grass Seed?

Graphic of a man spraying grass seed on his lawn

A beautiful, green lawn can definitely transform the look of a house and also provides an area for playing and lounging. Of course, achieving that even carpet of grass that many homeowners dream of has its challenges. 

Laying sod can be quite costly, and seeding your lawn is not only slow but also doesn’t always provide the most uniform results. That’s why many people are now starting to use spray on grass seed. 

But what is it, and how does it work? We’re going to fill you in on how this method may be the answer to creating the yard you’ve always wanted. 

What Is Spray on Grass Seed? 

Spray on grass seed is also known as hydroseeding or hydromulching. Basically, it’s a method of seeding a lawn by spreading a mixture of grass seed, fertilizer, mulch, tackifiers, water and sometimes green dye. This mixture is known as “slurry.” 

This technique is more cost-effective than laying sod and results in a faster-growing and more uniform lawn than the traditional seeding method. So why have you never heard of it? 

Hydroseeding has actually been around since the 1970s but was mainly used for growing commercial lawns or used by government agencies to reseed large areas of national land damaged by wildfires or mudslides.

But due to its effectiveness, many homeowners are now turning to this method to create residential lawns. Before we talk about the actual process of hydromulching, let’s cover its benefits. 

The Benefits of Hydroseeding 

As mentioned, hydromulching involves spraying a mixture of grass seeds, fertilizers, mulch and tackifiers. This mixture helps the lawn to germinate faster than regular seeding because of all the nutrients the slurry contains. 

Furthermore, the addition of tackifiers helps to hold the seed in place, so it won’t be washed or blown away. Ultimately, this helps the grass to grow more evenly and also makes hydroseeding suitable for planting grass on slopes. 

Costwise, hydroseeding is a middle-of-the-road choice (about $.07 to $.22 per square foot). While it’s more expensive than traditional seeding, it’s less expensive than laying sod. 

Finally, hydroseeding also allows you to choose a grass blend that’s suitable to the climate you live in, while the types of sod available may be more limited. 

To sum up the benefits of hydroseeding: 

  • Hydroseeding helps grass to germinate more quickly than traditional seeding
  • Protects seeds from wind and rain 
  • Helps for even grass growth
  • Less expensive than laying sod 
  • Allows you to customize your seed blend 
  • Suitable for growing grass on hard-to-reach and slopey areas 

The Drawbacks of Hydroseeding 

If you’re looking for a DIY approach to installing a lawn, hydromulching is not the simplest method. First, you’ll need to calculate the amount of slurry you need. You’ll also need a hydroseeder to spread the seed mix. A hydroseeder is a heavy piece of equipment from which the slurry is sprayed. 

These machines can be difficult to find and expensive to rent as they are usually geared toward contractors (rental costs can range from $250 to $500 per day). That being said, it’s not impossible if you’re a real DIY kind of person. If you’re not, you can hire a professional lawn company to do the job, which will add to the cost. That’s why hydroseeding is more cost-effective for larger areas of lawn. 

Hydroseeding also won’t give you the instant gratification of sod and needs to be on a very strict watering schedule for the first few months. And, of course, you’ll have to stay off the lawn until it’s well-established. 

To sum up the cons of hydroseeding: 

  • Hydroseeding can be a challenging DIY project 
  • Will not give you an instant lawn 
  • Requires a strict watering schedule for the first few months 
  • More expensive than traditional seeding 
  • Not as cost-effective for smaller properties 
  • You must stay off the lawn until it’s firmly established 

How to Hydroseed 

Graphic of a man spraying grass seed on his lawn

Whether you take a DIY approach to hydroseeding or decide to hire a professional, the procedure involves the same steps. 

Choose the Time You Hydroseed Wisely 

Because spring and early fall are usually wetter and milder times of the year, they make some of the best times to hydroseed your lawn. That’s because after hydromulching, the seeds require quite a bit of water. 

Just be sure you plant late enough in spring and early enough in fall to avoid frost, which can kill the seeds. In general, you’ll need to plant 45 days before the first frost if you decide on autumn. 

This doesn’t make summer hydroseeding impossible, but because it’s usually hotter and dryer at that time of year, your seeds will need more maintenance and water. 

Of course, all of this depends on the weather conditions where you live.

Test Your Soil 

No matter what kind of grass seed you select, a soil test is crucial. Grass grows best in a pH between 6.5 and 7. You can purchase a DIY kit or let a professional do the test. 

Once the results come back, you can adjust your soil as needed with organic materials and lime or sulfur amendments depending on its pH. 

Choose Your Grass Seeds 

Grass seeds come in a wide variety of species. The most important thing here is to choose a grass that will thrive in the climate where you live and the conditions of your yard (sunny, shady, etc). Depending on the conditions, you may want to choose a seed that’s heat-resistant, drought-resistant or even disease resistant. 

Your local garden center will probably have some good suggestions if this is a project you plan to take on yourself. Otherwise, a lawn care company can suggest the best grass for your area. 

Prepare the Ground 

Hydroseeding needs to be done on bare soil. That means you’ll have to get rid of weeds, dead grass, large rocks or other debris before spraying. 

Grade the Soil 

Next, you’ll need to grade the soil away from your home and a few inches below the final height you desire. This will help to prevent water pooling and keep the slurry away from your house, where it could cause moisture-related damage.

Apply Compost and Topsoil 

To give your grass all the nutrients it needs to thrive, you’ll want to apply an approximately 2-inch layer of compost and topsoil. 

Re-Grade the Soil 

Once you’ve added the compost and topsoil, you’ll want to smooth out your soil once again. 

Prepare the Slurry 

This is where you’ll choose the type of fertilizer, tackifiers and other ingredients that you’ll blend with your grass seed. 

Remember that tackifiers are especially important for sloped areas and will help to prevent soil erosion. Non-toxic green dye is often used when preparing slurry and will help to guide you in the consistent application of the mixture so that your grass grows in evenly. 

Prepare and Load the Hydroseeder 

If you’ve never used a hydroseeder before, it’s of utmost importance to learn how to prepare and use one. Be sure to follow the instructions in the manual for the specific hydroseeder you’re using. 

Spray the Hydroseed 

Now you’re finally ready to grab the sprayer and distribute the hydroseed! For uniform results, you’ll want to spray evenly. Again, this is where adding green dye to your slurry comes in handy. 

Hydroseed Maintenance 

To give your hydroseeded lawn the best chance of thriving, proper maintenance is vital. Here’s what you need to know: 


In general, you want to keep your hydroseeded area moist but not overly soggy. Once the slurry mixture is dry (which is usually the next day), you’ll want to establish a strict watering schedule. 

For best results, you’ll want to water 2 to 3 times per day for about 15 minutes using a light spray setting to avoid oversaturation and water pooling. 

Of course, the amount you water will also depend on the weather conditions where you live. In rainy and cooler conditions, you obviously won’t have to water as much. The most important thing to remember is to be sure the hydroseeded area doesn’t dry out between waterings and that it also doesn’t get oversaturated. 

Stay Off the Grass! 

To give your grass time to establish itself, you’ll want to avoid walking on it for between 5 to 12 weeks. The germination period will depend on the type of grass you choose and the weather conditions. 

You may see the first sprouts anywhere from 7 to 10 days. But until this young grass is better established, be sure that you, your kids and your pets stay off of it to avoid bare spots.

When to Mow 

You’ll want to wait until your grass is 3 to 4 inches high before mowing your lawn. Be sure to adjust the setting of your mower to remove only the top third of the grass. This will help to promote growth and help the grass to fill in areas that aren’t as well established yet. 

When to Fertilize 

You’ll want to wait a month before adding lawn fertilizer to your new lawn. Be sure to choose a fertilizer that’s appropriate for new grass. Slow-release formulas and well-balanced blends are a healthy choice for your lawn. 

When you fertilize, be sure the grass is dry and then give it a thorough watering after the fertilizer is applied. 


If you plan to use weed control products like herbicides or weed killers, be sure to wait 3 to 4 months before applying them on your lawn. This will give your grass time to grow in and establish itself. Also, be sure to select a weed control product that’s meant for new grass. 

Hydroseeding vs. Sod vs. Traditional Seeding 

Choosing the best method for growing a lawn will depend on various factors, including your budget, how quickly you want results, the size of your yard and if you have an already established (but perhaps patchy) lawn. 

Let’s review the options:


Sod is obviously the quickest option when it comes to installing a new lawn and will give your home instant curb appeal. It also doesn’t require as much maintenance or watering as a seeded lawn does initially. 

However, there’s a price to be paid for that convenience. Sod prices can run anywhere from $.35 to $.85 per square foot (not including labor), which is significantly more expensive than traditional seeding or hydroseeding. 

Sod is also available in a more limited variety of grass seeds. And because sod is cut and then installed, it’s not as hardy as grass that was grown from seed, so it might not be as good for high-traffic areas.

Traditional Seeding 

Lawn seed is the least expensive option and can be used to fill in an established but patchy lawn with bare or dog spots. Hydroseeding, on the other hand, can only be done on bare soil. 

The biggest drawback to traditional seeding is that it takes a long time for the lawn to establish itself. Yes, a hydroseeded lawn will also require time, but the seeds germinate and grow faster because of the nutrients in the slurry. 

Traditional seeding also leaves the grass seeds more vulnerable to being blown away by the wind, picked off by birds or washed away by rain. The end result is that your grass may not grow as evenly. 


One of the biggest advantages of hydroseeding is that it gives you very uniform results. Nutrients and tackifiers help the seeds to germinate more quickly (than traditional seeding) and also make them less vulnerable to wind or water erosion. 

You can also pick a blend of seeds that will grow best in the climate and conditions where you live, which is another factor in making hydroseeded lawns quite hardy. 

Hydroseeding is also less expensive than installing sod. The drawback is that the lawn will need time to establish itself and will need to be on a strict watering schedule, especially the first several weeks. 

Of course, hydroseeding is more expensive than traditional seeding and does require a hydroseeder to spread the slurry, no matter the size of the yard. That’s why hydroseeding may not be as cost-effective for smaller properties.

Hydroseeding also needs to be done on bare soil and isn’t intended to fill in patches of an already existing lawn. While there are DIY kits on Amazon for a Hydro Mousse Liquid Lawn system that is supposed to fill in bare patches of lawn using only a garden hose, the reviews are far from stellar. 

Is Hydroseeding for You? 

Again, you’ll need to consider your budget, the size of your yard and the amount of time you’re willing to wait before you choose the best method for creating a lawn for your home. 

But if you’re looking to spend less than you would on sod, have a fair sized property, and are willing to wait a little extra time to establish grass, hydroseeding could be the answer to growing a hardy, uniform and beautiful lawn.

You might also be interested in: Guide To Fertilizing Your Lawn [In 4 Simple Steps]

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