How Long Does It Take For Grass Clippings To Decompose

It can feel you’re flush with grass clippings throughout the summer lawn mowing sessions. Removing the grass clippings can be the most tiresome part of the lawn care treatment.

However, is it necessary to bag and remove grass clippings since they contain many nutrients that benefit your lawn?

You can use your clippings in the garden in several ways, from leaving them where they are to composting them.

No matter how you use them, they will return nutrients to the soil. Yet, you may think they are unsightly on your lawn and will add to a troublesome thatch layer.

grass clippings

In our guide, you can find out the answers to how long does it take for grass to decompose. For a heads up, it can take up to four weeks for grass clippings to decompose if left unattended.

Luckily, you can find out how to get grass clippings to decompose faster for quicker nutrient return and keep your lawn looking nice. (Read Fertilizer For Centipede Grass)

Will Grass Clippings Turn Into Dirt?

After mowing your lawn in late summer, grass cuttings will decay in 3–4 weeks on average.

Because grass clippings reach the soil level and decompose within 1–2 weeks, they are no longer visible. In 1–3 months, grass clippings put into compost will decompose completely.

Much of this will depend on the cutting process, length, and condition. You don’t want long clippings, whether you’re leaving them on the lawn, composting, or mulching them.

This is because larger chunks of organic matter take longer to disintegrate. Longer grass clippings can clump together and form thatch, a thick spongy matting, which comprises dry, dead plant material.

It’s difficult to remove, and it keeps water and sunshine from reaching anything beneath it.

Here are a few ways of how to decompose grass clippings naturally.


An inch-long clipping is ideal for the lawn. You can do this by raising your mower blades or using a mulching mower.

At no point should more than one-third of the grass height be removed at a time. Use a sharp blade, and mow cool-season grasses to 3 inches and warm-season grasses to 2 inches to keep them in tip-top shape.

After mowing the lawn, let the clippings fall around the roots. If the clippings are still on the grass leaves, rake them into the root area. (Read St Augustine Grass Fertilization)

The cuttings will decay in a few days. The length of this process depends on the weather. Grass decomposes quickly in hot climates. This may take longer in cold, dry locations as wet grass clumps, thus breaking down slower.

You may help the process by watering your grass regularly and picking up larger debris or stacks of clippings.

mulch dark


Making mulch from your yard clippings works similarly to leaving them on the grass.

After mowing the grass, collect the cuttings and trim them to an inch. Longer ones may need to be hacked. Skip this step, and you’ll end up with thatch on your flower beds, blocking water and sunlight from reaching the soil.

This mulch will degrade in a week or two if applied thinly to the soil, yet the matting occurs when soil bacteria can’t reach thick layers or clumps of debris. You can mix your mulch with wood chips to stop your grass clippings from becoming too thick and smelling.

You can turn regularly as you add more, so rotting grass and wood chips are in the soil rather than on the surface.

Compost Heaps

Composting piles take time to mature, as every gardener knows. You can use grass clippings to make garden compost piles, but the ratios must be correct.

Composting requires a 50/50 mix of grass clippings and dry materials like straw or leaves. Compost can be applied directly to bare soil or placed in a compost bin with dirt at the bottom.

Grass that is too thick can lead to an anaerobic breakdown, which is odorous, and this anaerobic decomposition doesn’t help nutrients for compost.

A well-managed compost pile will be turned over as it helps stop clumps from forming. Turn your pile once a week to break down and mix your compost and disperse the extreme heat it generates. (Read What Is Mushroom Compost)

Composting grass clippings takes about four months, depending on the mix and soil. It’s not an effortless task, but it’s worthwhile for healthy grass roots.

dried grass

How Do You Make Grass Clippings Decompose Faster?

Shred leaves to speed up decomposition and composting rather than taking a few months. Compost piles started in the autumn won’t be ready until early summer next year.

Non-shredded leaves tend to mat, blocking air and water and slowing decomposition. If you can’t shred your leaves and grass, mow them to cut them into smaller pieces. A mulching blade on your mower will shred your leaves even more.

To develop and metabolize, decomposing microbes require nitrogen. Decomposing leaves degrade slower than adding nitrogen to your compost pile. However, shredding leaves speeds their decomposition.

Grass clippings are abundant in nitrogen and will help decompose your leaves faster. Also, you can add a layer of soil or compost to your shredded leaves, and grass clippings may speed up the composting process.

Adding shredded leaves and grass to your compost pile balances the carbon and nitrogen. Grass clippings and kitchen scraps supply nitrogen to your compost pile, and you can also add nitrogen from used coffee grounds.

Composting your leaves and grass clippings properly speeds up decomposition and creates a rich, earthy compost that speeds up plant growth.

Putting leaves and grass clippings in a compost tumbler may help them break down faster, giving carbon and nitrogen to your plant soil.

Keeping compost moist like a wrung-out sponge but not overly wet minimizes odors. A well-tended compost pile heats faster than an unattended pile of damp leaves or grass clippings exposed to rain or excessive heat.

How Long Does it Take Grass Clippings To Turn Into Dirt?

Green grass clippings are a substantial source of free nitrogen. Microbes will decompose the grass into nutrients that your grass can need—no need for synthetic fertilizers with more nitrogen.

Boost soil organic matter. Organic matter benefits your soil in several ways, including enhancing moisture absorption, aeration, and feeding beneficial microbes, insects, and worms that break down organic matter into nutrients grass can absorb.

Organic matter in grass soil should be 3% and in garden beds and vegetable gardens 5%.

As grass clippings degrade, they shade the soil and prevent weeds. Soil shaded by weeds retains moisture longer, preventing weed growth.

After mowing, grass cuttings disintegrate in 3–4 weeks. Grass clippings frequently disappear after 1–2 weeks when they reach the soil and begin to decompose.

Is Rotted Grass a Good Compost?

Leave grass clippings on your lawn for enhanced grass health. Clippings improve lawn health as they decompose faster in your grass than elsewhere. Consider your grass clippings as nutrient-rich fertilizer, and you’ll find grass clippings are nutrient-depleted when bagged and moved.

By throwing lawn clippings away, you’re losing valuable soil nutrients. Lawn cuttings contain valuable soil nutrients. Robbing your garden of such nutrients naturally present if you eliminate grass clippings, you’ll need to fertilize more often to keep your lawn healthy.

De-thatching your lawn speeds up grass clipping decomposition, and you’ll discover thatch is not caused by grass clippings left on your lawn, although it slows decomposition.

Thatch is a layer of grass-root growth, runners, and stems between the grass and the earth, and over 1/2 inch thick, and this barrier stops grass clippings from reaching the soil and soil bacteria from breaking them down.

Heat and moisture degrade grass clippings. You can’t control the weather, but you can water your lawn. Watering your lawn deeply twice a week throughout the growing season promotes a healthy lawn and speeds up the breakdown of fresh grass clippings.

Mulch your garden with a 3–4-inch (7.5–10 cm) layer of grass clippings. Grass clippings make a good mulch because they protect your plants, suppress weeds, and retain garden soil moisture.

Plan to add new mulch every 2–3 months because grass clippings decompose in 2–3 months.

Grass clippings used as mulch decompose quickly. A 4-inch layer of grass-clipping mulch will entirely disintegrate in 2–3 months.

This is beneficial to your garden since all the nutrients in grass clippings will be used to nourish your plants. You’ll need to replace your grass clipping mulch 3–4 times a year, though.

When you leave grass clippings on the lawn, they decompose entirely in a few weeks.

Grass clippings decompose entirely in 1–3 months in compost.

3–4-inch grass clipping mulch layer: In 2–3 months, the body will be completely decomposed.

The fastest grass clipping breakdown rate is achieved by “grasscycling,” which let’s grass clippings fall back onto the lawn as you mow. (Learn How To Propagate Pothos)

Grass clippings are great for this application since they nourish your lawn, promoting future growth through the decomposition process. This decreases the demand for lawn fertilizer while also maintaining the health of your lawn. It also saves you the time and work of bagging and disposing of lawn clippings.

If your mower can’t operate without the bagging attachment, leave it in position and use these cuttings for your compost pile. It is a shame to waste all those nutrients.

Grass clippings are a natural fertilizer for lawn soil since they contain 4% nitrogen, 2% potassium, and 1% phosphorus. Leaving grass clippings on your lawn after mowing is called “grasscycling.” T” is a full decomposition method that has many benefits.

Grass clippings provide excellent mulch material. In your garden and flower beds, spread a thin layer of dried grass clippings (approximately 1-2′′). This will help prevent weed growth, retain moisture, and reduce erosion. In the soil, the grass will degrade into organic materials and plant nutrition.

Grass cuttings make excellent mulch—dry grass clippings (1-2′′) in your yard and flower beds. Weeds won’t grow, water won’t run off, and full decomposition decompose into organic materials and soil nutrients for a far healthier lawn.

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