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How to compost grass clippings after a day of lawn mowing

Whether mowing your lawn for the first time or in the middle of the growing season, you can easily turn your grass clippings into compost for your garden. Because it involves collecting the grass clippings, it will be much less of a task if you have a smaller lawn; however, it’s possible to do with any size yard and any amount of grass clippings, so long as you have the time to dedicate to the process.

Hands holding fresh grass clippings
Paula GC/Shutterstock

Before you add clippings to the pile…

You should know that composting isn’t your only solution! We’ll talk about some others later on, but as long as you’re cutting your lawn regularly, the grass clippings won’t pose any threat to new growth and can simply be left alone to naturally decompose; however, if your yard is longer than usual, you’ll want to remove a decent amount of clippings to avoid smothering the grass underneath.

If you’re interested in adding a rich source to your compost pile, though, then press on!

Know your compost composition

Knowing how to compost grass clippings starts with understanding what makes up a compost pile. Every successful compost pile needs three things: nitrogen sources (greens), carbon sources (browns), and water. Ideally, you want a balanced mixture of nitrogen and carbon, and enough water to give the pile some moisture but not so much that it’s soggy.

Fresh cut yard clippings are a green source, meaning they’ll increase the amount of nitrogen in your compost pile. When adding these to the compost pile, you should be sure to add a similar amount of a brown source (such as dry leaves or old, dried out yard clippings). Because dried out yard clippings count as a brown source instead of green, you could easily alternate when you add the clippings. Trim the yard, set aside those clippings to dry out. Then the next time you trim the yard, you can add equal amounts of the fresh clippings and the dried ones from last time.

Are herbicides a concern?

A common concern with composting yard clippings from a lawn that’s been treated with an herbicide is that they will cause harm to the compost pile. Most herbicides, though, are legally required to be able to break down in a few short days in order to be marked for use on lawns in residential areas. Caution should only be taken when using grass clippings from farms or large venues like golf courses. The herbicides used in these spaces can take weeks to break down, and as such aren’t recommended for compost piles.

Composting your clippings

Grass clippings can be composted similar to any other nitrogen-rich material that can break down in a compost pile. Special care should be taken with them, though. Because grass clippings are mostly water, it’s very easy for them to be compacted when put in the pile. You should be sure not to stuff them down when adding them. Too thick of a layer won’t break down properly and could cause a foul odor.

As long as you remain cautious about how many grass clippings you’re adding to the pile at any given time and make sure to balance them with a brown material, you should be good to go! A couple tips to keep in mind:
If you find your pile is full of grass clippings, give it a turn every few days with a proper tool. This will help speed the composting process along and introduce air into the pile.
Compost your grass clippings in thin layers and in a two-to-one ratio with a brown material to keep the balance.

If you’re looking for how to compost grass clippings fast, you may not find your answer. The best way to ensure a fast breakdown of materials is to keep your compost pile in a mostly perfect balance—equal parts nitrogen and carbon, and some moisture to help the process. A pile without the right balance will result in a slower breakdown.

Why compost clippings in the first place?

Because grass clippings are high in nitrogen (and available as long as you mow your lawn!) they’re a free, nutrient-rich source you can use on your garden beds. They’re a natural, organic way to give your plants some essential nutrients like potassium and phosphorous, and their presence in your compost pile won’t cause any harm to the soil organisms. Best of all, composting your grass clippings means avoiding spending money on hauling the clippings to a landfill (and as such, wasting perfectly good plant nutrients).

Gardener using dry grass as mulch

Alternatives to composting

If you’re not interested in composting grass clippings or live in an area where you don’t have room for a compost bin, there are other alternatives available before resorting to the landfill! As mentioned at the beginning, grass clippings can simply be left alone on a well-maintained yard. Small clippings will decompose with ease, giving the nutrients right back to the lawn they came from.

Longer clippings, like the ones you’ll get after the first mow of the season or after a few days of rain, should still be removed. The good news is that they can actually be used not just as compost but as garden mulch, too! When you use your yard clippings as garden mulch, you’ll want to give them a few days to dry out so that air is able to flow around them and the soil/plant life won’t be smothered. Never put more than two inches of clippings on the garden, and avoid using them right away if the lawn has recently been treated with an herbicide. This is because even though the herbicide will break down fine in a compost pile, it won’t break down right away on new clippings and could cause harm to your plants.

Once you know how to compost grass clippings, you’ll find yourself wondering why you ever treated them as yard waste. They’re full of nutrients, a free source of nitrogen, and can provide a lot of benefit throughout the growing season. After all, the lawn never stops growing.

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