How Much Peat Moss To Cover Grass Seed?

Getting new grass seeds to start germinating properly is often tedious and challenging, as the seeds are extremely fragile during the early growth stages. 

This is why it’s so helpful to cover your grass seed in something like mulch, hay, or, in this case, peat moss. 

But how much do you need to cover and insulate the seeds fully?

After you’ve planted your new grass seeds, cover the area entirely with at least ¼” to ⅓” inches of peat moss. This will keep the underlying soil moist and protected from pests and the elements, provide nutrients to the seeds, and allow the seeds to germinate more quickly than usual.

Keep reading to learn more about using peat moss on grass seed, why it’s so great for newly-planted seeds, what kinds of alternatives there are to peat moss, and more. 

Soon, you’ll have lush, green grass seedlings sprouting up in your yard, all thanks to a simple protective layer of moss.

how much peat moss to cover grass seed

What Is Peat Moss?

Peat moss is a general umbrella term for almost 400 unique species of mosses within the Sphagnum genus. 

It is a dead material harvested from peat bogs in swamps and wetlands after sufficiently decomposing. 

Over time, various kinds of plant matter break down while submerged in water, resulting in the formation and accumulation of peat moss.

It doesn’t contain any actual soil, but it is used for many of the same purposes as soil, namely as a growth medium for various plants. It is also often added to soil to improve its texture.

In this case, we’ll be talking about using peat moss as a protective coat for your newly-planted grass seeds to both nourish them and assist them with fast and healthy germination.

Peat moss has a lot of great qualities, which make it an excellent growth medium and soil amendment, including its fairly acidic pH level ideal for various plants, its moisture-rich composition, and its rich in nutrients. 

It works well for protecting both newly-planted cool-season grasses and warm-season grasses, making it quite versatile for coverage and a nutritional boost for grass seedlings.

In addition to these factors, peat moss is great for keeping soil aerated and preventing it from becoming compacted. 

It’s light yet absolutely packed with moisture and nutrients, and in a lot of cases, it’s even better than compost or soil. 

If you do want compost, check out our picks for the best bagged compost.

Many flowers, vegetables, fruit trees, grasses, and other plants benefit greatly from a bit of peat moss in their soil, and it even helps to protect their roots from drying out or becoming damaged.

Why Should You Cover Grass Seed With Peat Moss?

While peat moss is a fantastic soil amendment and growth medium in general, it’s also especially great for covering newly-planted grass seeds you want to germinate and sprout as quickly as possible. 

It’s light enough to allow nutrients and water to flow into the soil with ease, yet it’s just heavy and dense enough to also prevent the new grass seeds from washing away when faced with heavy rain and winds. 

Plus, thanks to its nutrient-rich composition, peat moss will play a major role in encouraging faster germination than other materials commonly used to protect new grass seeds, such as hay and straw, for example.

It’s also dense enough to keep insect pests and other animals from digging up and eating the seeds. 

What’s more, you don’t even need to remove the peat moss or worry about it later since it breaks down on its own as the seeds slowly absorb and consume its nutrients and moisture.

Another great thing about peat moss is its low cost. 

It is easy to find from online retailers or your local garden center for as little as $10 to $20 for 15-pound bags of peat moss, which easily covers a fairly large area of grass seed. 

If you have any left over after you’ve planted your grass seed, you have the option of adding more later to further assist in germination or use it for other plants in the place of or in addition to standard potting soil.

Learn more about how long it takes grass seed to grow.

What Is The Difference Between Peat Moss And Soil?

Both peat moss and potting soil are used for many similar purposes, but they have several key differences in their composition, efficacy, and more. 

To start with, peat moss contains no soil and is entirely made up of decomposed plant material which has slowly transformed into moss over time after being submerged in water.

Soil, on the other hand, is made up of: 

  • Both Dead And Living Microorganisms
  • Minerals
  • Inorganic And Organic Matter
  • Air 
  • Water

Although it looks similar to peat moss, it is very different in its nutrient composition, weight, texture, and overall moisture content. 

Peat moss is often added to potting soil to make it lighter and increase the mobility of water and nutrients to the seeds and/or plants housed within.

While both soil and peat moss have similar uses, peat moss is far more beneficial when covering and protecting new grass seeds while they germinate and sprout. 

Soil is too heavy and dense to coat most grass seed varieties, which means it often results in the suffocation of the seeds because water and other nutrients cannot move through the soil layer.

Peat moss is much more nutritious for the grass seeds during the early growth stages. 

Since the peat moss is so light and easy for these nutrients to move through, they can quickly access the seeds and nourish them while they begin to germinate. 

As a result, the germination process is sped up, and the resulting grass is stronger and healthier once it eventually sprouts!

How Much Peat Moss Do You Need To Cover Grass Seed?

Covering grass seed with peat moss is fast, simple, and inexpensive, making peat moss a popular choice as a protective layer for newly-planted lawns. 

It works well for virtually all grass seed species, and it is safe to use just about anywhere, aside from, perhaps, steep slopes where it has the chance of eroding or washing away due to its being extremely lightweight.

Once you’ve planted your new grass seed, you’ll need to get to work covering it with your nice, moist peat moss. 

Exactly how much you’ll need will vary significantly depending on the size of the area where you’ve planted the seeds, how densely you’ve planted them, and where you’ve planted them (as we mentioned earlier, peat shouldn’t be used on steep slopes).

It’s hard to say exactly how much peat moss you’ll need to cover your entire lawn, but one cubic yard of the stuff is usually enough to cover 1,000′ square feet of lawn area. 

Regardless of the size of the area, cover the seeds between ¼” inch and ⅓” inch with peat moss. 

This probably seems like it isn’t enough, but this is another wonderful quality about peat moss–you don’t need much of it for it to be effective!

Even a quarter-inch layer is more than enough to protect the grass seeds without suffocating them or keeping them too insulated. 

It’s also enough to keep most animals, pets, and other garden pests away from digging them up and disturbing them, as the peat moss is quite acidic and not particularly attractive to most pests.

Simply water as usual once you’ve covered the new grass seeds with a thin layer of peat moss. 

You don’t need to do anything else after this. 

You won’t even have to remove the peat moss later as you might need to with straw or other materials commonly used to protect new grass seeds, as it will break down gradually on its own. 

Plus, the decomposing material will provide more moisture and nutrients to the seeds, in turn speeding up the germination time and ensuring you end up with thick, lush, green grass.

Is Peat Moss The Same As Sphagnum Moss?

Though the terms are often used interchangeably, peat and sphagnum moss aren’t the same thing.  

While it’s true peat moss is a member of the Sphagnum genus of mosses, the term “peat moss” actually refers to various types of dead and decayed sphagnum moss which have been saturated and submerged in water for an extended period.

On the other hand, Sphagnum moss is still alive and has slightly different uses than peat moss. 

They’re parts of the same plant, just at different stages of growth! 

Don’t be too surprised, though, if you see peat moss labeled as “sphagnum peat moss,” as again; the two terms are often confused.

What Can You Use Instead Of Peat Moss?

If you don’t want to use it for whatever reason, you do have a few peat moss alternatives. 

Namely, you don’t want to use peat moss on steep hills or slopes. 

Because it is so light, moist, and airy, peat moss tends to erode and wash away quickly in heavy rains and windy conditions, so it’s best to use something a bit heavier in such cases.

Alternatively, the acidity of peat moss is an issue for some lawns. 

You won’t want to use peat moss if your soil is already very acidic, as it also has a very acidic pH level. 

Peat moss harvesting is also environmentally unsustainable and has resulted in quite a bit of controversy over peat moss in recent years, so this is also worth considering.

Straw or hay is your best and most eco-friendly choice compared to peat moss. 

These materials are also slightly heavier, so they stay put on inclines much better. 

However, because they are still fairly light and biodegradable, they will provide nutrients to the soil and seeds underneath and encourage healthy growth and germination.