Grass Clippings as Compost

Guide to Using Grass Clippings as Compost

During the spring and summer months, homeowners collect heaps of grass clippings from their lawn only to throw them away. Since grass clippings are an excellent source of nutrients there is no need to bag them. Instead of tossing your yard waste to the curb, enhance your compost pile with grass clippings. You’ll be reducing waste that would otherwise be in a landfill and converting your grass clippings to rich soil amendment for your lawn and garden.

Trust and Accuracy Information

This article was last updated on by Lawn Chick Owner Sarah Jameson
Article content reviewed for accuracy by Certified Horticulturist Nicole Forsyth, M.S.

In this guide to using grass clippings as compost I’ll walk you through

  • The basics of composting,
  • Why grass clippings make excellent fuel for your compost pile,
  • Things to be careful about or avoid, and
  • Whether or not you should even bag your grass clippings (vs. mulching them back to the lawn).

Let’s dive in! is reader supported. If you make a purchase after clicking a link, I may earn a commission at no additional cost to you.

An Introduction to Compost

How to Use Grass Clippings as Compost

Compost, otherwise known as black gold, is decomposed organic material rich in nutrients.

While it can take between 1 and 6 months until hot compost is ready, this is one of the best plant foods for gardens and lawns. Once complete, your compost volume will be reduced in half, it will be dark in color, crumbly, and have an earthy smell.

Often used for topsoil, mulch, and plant nourishment, compost is a must-have for homeowners looking to nourish their garden and lawn.

Since grass clippings are nitrogen-rich and are easily available, they are ideal for compost when combined with carbon-rich materials.

There is more to composting grass clippings than tossing them aside expecting rich organic matter a couple weeks later.

A proper compost pile needs maintenance, patience, and work … but the results are worthwhile.

Composting Grass Clippings

Before composting your grass clippings, it is advised to conduct personal research on any treatment your lawn has received.

For homeowners concerned about grass treated with herbicides, pesticides, and insecticides it is best to contact your lawn care provider to know what treatment (if any) where used and if it’s safe for compost.

If you’re mowing your own lawn, then you probably already know what products you use. And if you’re using organic lawn fertilizers and natural weed control methods … you’ve got nothing to worry about.

3 Stage Composting Setup
A 3-stage composting set-up

Using Grass Clippings in a Healthy Compost Pile

In order to generate heat, a compost pile requires a balanced mix of brown (carbon-rich) and green (nitrogen-rich) material.

Fresh greens provide energy to microbes while brown material supplies proteins to them.

Green (Nitrogen) Materials for Composting

Green materials include fresh grass clippings and weeds because of their high nitrogen and water content.

Grass clippings are a great addition to the compost mix. Household products and foods like coffee grounds, vegetable peels, and eggshells are considered green material as well.

Brown (Carbon) Materials for Composting

Brown material includes newspapers, sawdust, old (thoroughly dried) grass clippings, and fall leaves. These materials are low in nitrogen and carbon-rich.

Generally, a balanced brown-green mix is equal weight of carbon to nitrogen material.

My Composting Blend

I usually aim for a 2:1 ratio of brown to green material. I use shredded paper and junk mail, and sawdust from my husband’s workshop for the carbon and grass clippings, coffee grounds, and veggie scraps from the kitchen for most of my nitrogen.

What to Avoid

Since grass grows in abundance and is easily available, it’s tempting to source all of your green and brown material from fresh or dried grass clippings. However, this can cause a couple of problems.

Composting Grass

The first is a lack of diversity in your compost pile. It is important to diversify nitrogen and carbon sources to make the most of your compost. Therefore, grass clippings should be added in addition to other sources.

Secondly, excessive use of fresh, green material can mat or rot your compost pile. Because fresh grass clippings are mostly water and contain low levels of carbon, they can easily mat and rot if not dried or aerated regularly.

When used properly, grass clippings are a great source of nitrogen for composting.

To avoid compaction and killing microbes, routinely aerate your compost with a fork or compost tumbler (I use a couple of these ones from Amazon).

Bagging Grass Clippings for Compost

Compaction occurs when compost is not frequently turned and there is no opportunity for air pockets to form. Sometimes, microbes do their job too well and consume all the nutrients and oxygen.

Overheated and deprived of nutrients and oxygen, microbes eventually decay. Depending on the size of your compost pile and brown to green mixture, it is recommended to turn your compost pile every 3-7 days.

Should You Even Bag Your Clippings?

An alternative to composting is using a mulch mower to return the grass clippings back into your lawn.

Otherwise known as grass cycling, recycling your lawn’s clippings is a great way to recycle nutrients and reduce thatch.

Since grass clippings are mostly water and have a high decomposition rate, most homeowners decide to leave the clippings on the lawn as a natural fertilizer.

While grass cycling is recommended, there are instances where composting yard waste is more convenient than mulching grass clippings back into your lawn.

Composting Grass Clippings for Aesthetics

Some people prefer to bag or compost their yard waste for aesthetic purposes or because they do not want to track the clippings into their home.

Lawn Grass

But apart from aesthetics, there are additional disadvantages to recycling grass clippings into lawns. Yards that are overgrown or wet often leads to clumping of grass. These clumps of grass clippings, if left on the lawn, can discolor and smother your lawn.

There are a couple of remedies for this – either collect the clumps or go over the lawn again to break the clumps into smaller pieces. Both can be time-consuming.

Other things to avoid with mulching lawn mowers are large quantities of leaves and weeds. Many lawn mowers (especially older ones) cannot handle an abundance of leaves. If ignored, these leaves can clog motor blades and put undo strain on your mower’s engine.

In addition to excess leaves, weeds, like dandelions, knotgrass, and crabgrass should not be mulched. Mulching returns the clippings back into your lawn and in so doing you risk spreading weed seeds throughout your lawn.

But for composters, dried leaves are excellent for aeration and supplying microbes with protein. And weeds are ideal green material. They break down easily in compost and microbes will consume those pesky weed seeds for you.

Using Grass Clippings as Compost Can Be Great

Composting your grass clippings is a great way to recycle essential nutrients. And you’ll be reducing waste that would otherwise be in a landfill.

All About Using Grass Clippings as Compost

There are a number of household foods and products which, when paired with grass clippings, will work wonders to create rich organic compost for your lawn and garden.

The composting process can take a few weeks but the results are worth the wait. Your homemade compost can be applied as topsoil, mulch, and plant nourishment. Every second or third year I use compost to top-dress and feed my lawn after I aerate and overseed it in the fall.

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Sarah Jameson’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.

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