how much grass seed per square foot

How Much Grass Seed Do I Need Per Square Foot?

If you have decided that now is a good time to overseed your lawn or even seed a brand new lawn, one of the most important things you’ll need to know is how much grass seed coverage you need. 

Most bags of grass seed will recommend around one to five pounds of seed for every 1000 square feet, regardless of the type of grass seed you are using. However, there are intricacies involved in this and some warm season grasses may suggest applying less seed. 

There are other factors that will also affect how much grass seed per square inch or square foot. This might include whether you are seeding a new lawn or just touching up an existing one. If you want to make sure that your lawn is lush, green and healthy then using the correct amount of seed is essential. 

In this guide, we’ll cover everything you need to know about using the right amount of grass seed for a lawn that you can be proud of.

Working out how much grass seed you need per acre comes with some simple mathematical requirements. Generally speaking, anything to do with lawn care will be measured in square feet so you’ll need to convert every acre of your garden to match with this.

In a single acre, there are 43,560 square feet which gives us a nice base to work from. Since most grass seed bags suggest using between one and five pounds, let’s go right down the middle and assume we’re being advised to add 3lbs per 1000 square feet.

By this thinking, we would need to divide 43,560 by 1000. This equals 43.56 which we then need to multiply by the number of pounds required per 1000 square feet, in this case, that’s 3. So the equation would be as follows:

43,560 / 1000 = 43.56

43.56 x 3 = 130.68

That means that you’ll need around 131 pounds of grass seed to cover a lawn that measures one acre.

How Much Grass Seed For Overseeding?

If you already have an established lawn but it’s looking a little sparse and needs to be reseeded then there are a lot of variables on how much grass seed to use. This may depend on the type of grass seed you go for including whether it is a cool or warm season variety.

If you choose a cold weather grass like Kentucky bluegrass, tall fescue or perennial ryegrass then the advised amounts on the bag may vary for every 1000 square feet. This is largely because the different seeds come in different sizes. If you compare tall fescue seeds and perennial ryegrass seeds with Kentucky bluegrass seeds, you’ll notice that the latter are much smaller. This means that a pound of Kentucky bluegrass seeds contains a lot more individual seeds.

It’s also worth noting that Kentucky bluegrass is rhizomatic. This means that the grass will grow sideways as well as downwards. When this happens, the roots spread laterally and then come back up through the soil in other areas. If you want a healthy lawn, it’s often advisable to mix a rhizomatic grass with another type of seed.

With all of this in mind, here are our recommendations for how much grass for overseeding, based on grass type.

Grass Type Lbs Per 1000 Square Feet
Kentucky bluegrass 2lbs
Perennial ryegrass 5lbs
Tall fescue 5lbs

overseeding requirements

How Much Grass Seed For A New Lawn?

Seeding a new lawn comes with a whole new set of rules. It’s important to make sure that you correctly measure your lawn before you get started and we’ll cover how to do this accurately later in this guide. Also be sure to take the time to choose the right grass seed for your local climate and the needs of your garden.

Generally speaking, for a new lawn on totally bare soil, you’re going to need at least 7lbs of seed for every 1000 square feet. But again, this will vary according to the size of the grass seed with Kentucky bluegrass needing much smaller amounts owing to the small size of the seeds.

Grass Type Lbs Per 1000 Square Feet
Kentucky bluegrass 4lbs
Perennial ryegrass 10lbs
Tall fescue 10lbs

grass seed requirements for a new lawn

It’s also really important to make sure that you have some grass seed left over. This will ensure that, if there are any patchy spots, you can tend to these without having to go back out and buy more seed. For this reason, we’d suggest buying a little more than you need.

How To Calculate The Area Of Your Lawn

If you have a rectangular or square lawn then getting the measurement for the area is incredibly simple. All you need to do is multiply the length by the width and this gives you the area. Whether you measure in metres or feet, you’ll still get an accurate calculation.

If your lawn is a circular shape then it’s time to go back to school because you’re going to be using pi. All you need to do is measure the radius of the lawn and multiplying this by two and then multiplying by pi:

Radius x radius x Pi

There are some lawns that have an irregular shape but that doesn’t mean that you can’t get an accurate area measurement. The best way to do this is to divide the lawn into square or rectangular sections and take the measurements for these before adding them all together for the total area. In some cases, you might not get it spot on, but you’ll get it close enough to determine the right amount of grass seed.

When Is The Best Time To Put Grass Seed Down?

If there’s one question that everyone wants to know when it comes to planting anything, it’s when is the best time to do it. This is something that so many people ask when seeding a lawn but there is some good news.

Unlike a lot of plants, there isn’t really an ideal time to put down grass seed although different grass seed bags will offer different advice. For example, sowing cool seed grass in the height of summer isn’t going to yield the best results. This is regardless of how much seed you use or how well you fertilize it.

If you sow cool weather grass seed at the beginning of fall then the results will be much more impressive. The air won’t be as warm but the soil will still be warm enough to encourage germination.

However, you can, in theory, sow grass seed at any time of year provided you take certain things into consideration such as whether you are overseeding or laying a new lawn, how much sun and shade there is and how often the grass is watered. Also be sure to follow the pack instructions to the letter if you want the best results.

grass seeds

Different Types Of Grass Seed

As you may have guessed by now, there are several different types of grass seed. Which you choose will largely depend on your local climate since most grass seeds fall into either a warm season or cool season category.

Warm Weather Grass

You would use warm season grass seed in climates that have much hotter temperatures throughout summer and milder winters. For those of you living in the USA, this generally refers to the more southerly states where temperatures in summer are consistently between 75 and 90ºF.

There are lots of different varieties of warm weather grass but some of the most popular include Bermuda, centipede, bahia, St Augustine and zoysia.

Cold Weather Grass

Conversely, there are also cold weather grasses which, as the name suggests, do better in climates where the summer temperatures are a little cooler, around 65 to 80ºF. The winters in these areas are normally colder and the grass can stand up to this.

Again, you’ll find that there are a lot of cool weather grass seeds to choose from. Some of the most common are Kentucky bluegrass, tall fescue, bent grass, rough bluegrass, creeping fescue and perennial ryegrass.

FAQ

It is possible to add too much grass seed. They say you can have too much of a bad thing and that applies in your garden as well. If you apply too much seed to the lawn then you will probably find that it doesn’t grow as well. Stick to the measurements on the pack for the best results.

If you are unsure then you could test this theory. Pop a pile of grass seed in a pot or on an inconspicuous area of the lawn and watch how it grows. Things might start out looking good but before long, the grass will start competing with each other for water and nutrients. Eventually, this competitiveness will mean that the airflow in the soil is inferior and disease will begin to spread.

If this doesn’t happen, the sheer amount of grass will mean that they choke one another and die. So don’t be tempted to go over the top.

Working out how much grass seed is simple using the calculations that we have discussed in this article. There are also plenty of useful grass seed calculators online which allow you to figure things out much more easily. You’ll pop in the length and width of your lawn and the calculator will work out exactly how much seed you need.

How much lawn a 50lb bag of grass seed will cover really depends on the type of grass seed you are using. Typically speaking, a 20lb bag will cover anywhere between 5000 and 12,000 square feet if you’re seeding a new lawn. The same amount would overseed an existing lawn anywhere between 8000 and 16,000 square feet. Using these numbers, you can work out how much a 50lb bag would cover.

A lot of people think that putting soil over the top of grass seed will offer added protection. Unfortunately this is not the case and far too many people end up with grass seeds that won’t germinate because they have been suffocated by the soil. That said, it is possible to put a light layer of organic matter over the seeds to encourage germination.

Summary

Having a beautiful lawn is something we all want but in order to get that, we must make sure that the lawn is correctly seeded. Using too much could result in the grass competing with one another and dying off but not using enough won’t give you a dense, healthy lawn.

The packet of grass seed will provide you with information on how much to use per 1000 square feet but this depends on several factors including the type of grass. The tables in this article provide you with a rough guide on how much grass seed to use when overseeding and seeding a new lawn so you can get things spot on.

Further Reading

Andrew Fisher

Andrew Fisher

Andrew is a dedicated father of three who really takes pride in his lawn and garden. You'll find Andrew behind the scenes of almost everything Edge Your Lawn produces. When he's not helping readers find all the information they need, he's in his backyard working on his lawn and garden landscaping. This year he hopes to build an outdoor deck and sort out his veg patches.

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