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Will Compost Kill Grass? Tips For Using Compost On Grass

If your lawn is suffering from too much grass and not enough greenery, then you may want to consider adding extra nutrients to your grass. Many great soil amendments will help your grass stay green, but will adding something that is as nutrient-dense as compost to your lawn kill it rather than help?

Compost will not kill your grass if it is needed. Compost can actually be a wonderful way to make your grass greener. However, there are some other things you need to pay attention to if you want it to work well. If you compost when it’s not needed, you can end up killing your grass.

Compost will help your grass to grow because it is loaded with nutrients and beneficial microbes. It also helps the soil beneath your grass stay healthy so grass can grow better. Compost also isn’t the only thing that can help keep your lawn healthy.

Should I Spread Compost On My Lawn?

Before spreading compost on your lawn, you should figure out if that will mend the problems you’re having with your lawn. You should only spread compost on grass like Kentucky Bluegrass, Bermuda grass, or other grasses that need help with their growing conditions.

You should spread compost on your lawn if:

  • Your grass is struggling to grow due to not having enough nutrients in the soil.
  • You want your grass to grow better.
  • You see grass growing where you wouldn’t expect grass to be growing.

Compost isn’t always necessary to maintain a lawn’s health. There are also times (source) you shouldn’t spread compost on your lawn, such as during the summer or when there will be a lot of foot traffic on your lawn.

When you Shouldn’t Spread Compost on Your Lawn

You shouldn’t spread compost on your lawn if you have grassy turf grass. If you do not know what grass you have in your yard, ask a professional to identify grasses and grass types in your lawn. This will help you know what type of grass care will be needed most effectively.

Compost will not help the grass grow or be healthier if:

  • You have already mowed the grass on that part of your lawn, so it is no longer growing.
  • You put compost down when your grass is already thriving.
  • If you have grass that needs to grow thicker as opposed to grass needing more nutrients.
  • If weeds are growing on your lawn
  • If your grass is already dead or dying. The compost will send nutrients to areas that are already healthy but not those in need of nutrients.

Compost can kill grass by feeding the weeds as well. This can be a problem when the grass is not thick enough to cover and block out sunlight from grassy weeds such as crabgrass, dandelions, foxtail grasses, and other grasses that may look like grass but are actually weeds.

Nutrient Breakdown for a Healthy Lawn

Just like all plants, grass needs three main nutrients: nitrogen, phosphorus, and potassium. All types of grass require the same ratio of these three nutrients, so if one grass type receives too much or not enough of any of these three nutrients, it can be negatively affected.

You can find all of these nutrients naturally in compost. Compost is the product of grass clippings (or any plant material) that has been broken down by bacteria, and the nutrients have been released into nutrient-rich soil. 

The number of nutrients you’ll need for your lawn will slightly vary by the type of grass you have. If you have grass that requires more nitrogen than most grasses, such as Bermuda grass, you’ll need to use compost with higher nitrogen levels.

Here’s a quick video about spreading compost on a lawn, with more info below:

How Do I Spread Compost On My Lawn?

Once you know that you need to compost your lawn, you can spread compost either by hand or with a spreader. Spreading by hand is ideal for a small area, whereas using a spreader would be better for a larger area. Also, ensure you’re not laying the compost on too thick, or else it could kill the grass.

If you are using grass clippings that are dried but not composted, just throw them down over the grass in question and step on them to help get the compost into the grass roots.

If your grass clippings are less than an inch long, you don’t even need to worry about removing them unless you want to compost a specific area.

If you choose to spread compost on grass, don’t do it right after the grass has been cut because grass clippings from the freshly cut grass will turn into a mat, and you’ll have trouble spreading them around; grass clippings should be dried before using to make it easier to spread.

Advantages and Disadvantages of Using Compost on Your Lawn

Using compost on your grass has many advantages if used properly, such as:

  • It prevents grass from turning yellow due to the grass getting the right nutrition; having just enough nutrients is key for grass, and compost provides that.
  • It helps grass grow strong roots because compost has many nutrients that grass needs to keep its health and strength.
  • It also encourages grass growth by breaking down the architecture of the grass into simpler forms that make it easier for grass to grow.
  • It improves soil structure making it more porous, giving air entry so grass can breathe properly.

If you use compost on your lawn incorrectly, there will be some drawbacks, and you could end up ruining your lawn as well, such as:

  • Grass root burn, where the grass doesn’t get the right nutrition and dies
  • Grass diseases such as fungus and mold
  • It can be expensive, and it requires a lot of time because you probably won’t see instant results.

Topsoil vs. Compost for Grass

If you don’t need to compost your lawn, you can use topsoil. Topsoil is made up of grass clippings, grass trimmings, and grass roots. It includes everything except the grass blades.

Topsoil is cheaper than compost, but it still allows grass to grow. However, topsoil isn’t as good as compost for grass growth because topsoil contains fewer nutrients and organic matter, so grass’s growth might be limited.

Compost will also feed topsoil to make it more nutritious if you bury the compost. Topsoil is usually combined with compost to have the healthiest lawns.

Can you Compost Just Grass?

Compost is made up of decayed organic materials. To have a healthy compost pile, you need to have a mixture of different types of organic material.

For a more complete list check out our What You Can Compost List Here.

However, grass can be added to compost. When grass is composted with other materials, it adds some organic matter and nutrients. Then when the grass decomposes inside the compost pile, it adds more organic matter and nutrients, including nitrogen and carbon, which grass needs.

Turning Your Lawn Clippings into Compost

One important part of making compost is taking care of it. If you want to use grass clippings as an ingredient, you need to bag them right away, so they don’t start decomposing on your lawn. You should also keep grass clippings and other compost ingredients well-watered while they are in the compost pile.

When grass is decomposing, it can create heat inside a compost pile. This is usually bad because high temperatures in compost piles can kill grass bulbs and other plants you might want to include in your compost. Make sure you turn your compost pile regularly because grass holds a lot of moisture and can produce ammonia, which will kill plants.

Some other organic materials you can add to your compost pile are:

  • Brown leaves
  • Plant clippings
  • Food scraps (no meat)

For a more complete list check out our What You Can Compost List Here.


The key to successfully utilizing compost in your yard is understanding how to use it properly. If your goal is to have a healthier lawn, compost will help your lawn in many ways; however, you can also use compost to kill grass that is growing in places you don’t want it to grow. Even though compost is expensive, you can also create your compost with your grass clippings.

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