How to Compost Grass Clippings Fast

Composting grass clippings is a great way to recycle the waste from your lawn and create rich fertilizer for your garden. However, grass tends to decompose slower than other compost materials. The high nitrogen content in grass can also lead to a stinky, anaerobic pile if not managed properly. With some simple strategies, you can speed up the composting process and turn grass clippings into “black gold” more quickly.

Why Compost Grass Clippings?

Rather than sending grass clippings to the landfill or leaving them to sit on your lawn, composting offers many benefits:

  • Provides free fertilizer: Finished compost contains nitrogen, phosphorus and potassium which are nutrients plants need to grow. It will enrich your garden soil each time you spread it.
  • Reduces waste: Up to 500 pounds of grass clippings can be produced per 1000 sq ft of lawn in a growing season. Composting recycles all this material.
  • Improves soil structure: Compost contains organic matter that helps soil retain moisture and nutrients. It also creates spaces for air and water circulation.
  • Helps the environment: Composting grass clippings keeps them out of landfills where they take up space and release methane as they decompose.
  • Saves time raking or bagging clippings: Leave them on the lawn or add them straight to your compost pile.

Challenges of Composting Grass

While composting grass clippings has many advantages, it can be slower and trickier than composting other organic waste. Here are some of the challenges:

  • Slow to break down: Grass contains lignin and cellulose which take longer to decompose compared to fruit and vegetable scraps.
  • Risk of matting: Fresh grass clippings tend to clump together into dense mats. This slows decomposition and airflow in the pile.
  • High nitrogen content: Grass is very “green.” Having too much green material and not enough browns makes it difficult to balance the carbon-to-nitrogen (C:N) ratio.
  • Potential odor: With excess nitrogen and moisture, grass can become anaerobic and start to smell like ammonia.

Don’t let these potential issues stop you from composting grass. With the right techniques, you can overcome them.

Tips to Speed Up Grass Decomposition

It is possible to compost grass clippings quickly if you use the right methods. Here are tips for fast grass composting:

1. Shred the Grass Finely

Breaking grass clippings into smaller pieces gives bacteria and fungi more surface area to work on, speeding decomposition. You can use a lawnmower, weed whacker or leaf shredder to chop clippings.

Aim for pieces 1 inch or smaller. The more you shred the grass, the faster it will compost.

2. Maintain Proper Carbon-to-Nitrogen Ratio

The microorganisms that break down compost need about 30 parts carbon for every 1 part nitrogen. Grass alone has a C:N ratio around 15:1 or 20:1.

To adjust the C:N ratio, mix grass clippings with high-carbon “browns” such as:

  • Dry leaves
  • Sawdust
  • Wood chips
  • Paper/cardboard
  • Straw

Adding 2-3 times as much browns by volume to greens will create the ideal balance for active composting.

3. Turn and Aerate the Pile

Turning or stirring the compost pile brings in oxygen while redistributing material. Both fresh air and mixing are crucial for preventing anaerobic conditions.

Aim to turn over the pile with a pitchfork or compost aerator 1-2 times per week. Break up any clumps of grass you find while turning.

For faster composting, some sources recommend turning the pile daily or even twice daily. The more the better!

4. Monitor Moisture Levels

Microorganisms need moisture to decompose organic matter. But too much moisture in the pile leads to anaerobic conditions.

The compost should have a moisture content of 40-60%. Grab a handful and squeeze – it should feel damp like a wrung-out sponge. If drier, spray water while turning the pile.

Also cover the pile to retain moisture. Turning less often during dry or hot weather helps limit moisture loss.

5. Manage Particle Size

Along with shredding the grass, chopping or grinding other compost inputs makes them easier for microbes to digest.

Aim for a range of particle sizes in the pile. Having various sizes creates air pockets for oxygen flow. The smaller pieces also break down rapidly.

6. Prevent Compaction

Avoid compressing the compost pile by stepping or pushing on it. Fluff up the pile while turning it.

You can place branches or twigs at the bottom or bury them in the pile to create air channels. Chipping larger woody items helps too.

7. Get the pile hot

Heating the compost pile will accelerate the breakdown of grass. Internal temperatures between 130-150°F kill pathogens and weed seeds while speeding decomposition.

To achieve this, make sure to:

  • Chop materials finely
  • Maintain aerobic conditions
  • Use a large volume – at least 3x3x3 feet (1 cubic yard)
  • Monitor moisture
  • Turn or stir frequently

The center of the pile should feel quite hot to the touch when it is cooking at optimal temperatures.

8. Add compost accelerators

Certain amendments can provide organisms, enzymes or nutrients to further speed up grass decomposition. Common compost accelerators include:

  • Manure – provides microbes and nitrogen
  • Coffee grounds – contain nitrogen
  • Comfrey leaves – have enzymes that break down cellulose
  • Seaweed or kelp – high in microorganisms and growth promoters

Sprinkle in small amounts of accelerators each time you turn the pile. Don’t overdo it as they can affect the C:N ratio.

9. Try trench composting

In trench composting, you bury compost materials in shallow trenches in the ground. This method provides earthworms and beneficial soil microbes direct access to the grass for faster breakdown.

Dig trenches 8-12 inches deep in garden beds or where you want to add compost later. Fill with grass clippings and cover back over with soil. The compost will be ready in 1-2 months.

Repeat the process as you generate more grass clippings through the season.

How Long Does it Take to Compost Grass?

The speed of grass decomposition depends on the techniques used, time of year and climate conditions. Here is a general timeline:

  • 2-4 weeks with frequent turning, ideal moisture, particle size and pile size
  • 4-6 weeks if turning weekly and ensuring proper aeration
  • 2-3 months with minimal care of the pile
  • 6 months to overwinter grass in a pile with no turning

The more effort you put into managing the compost, the faster you will get results. But even an untended pile will eventually break down the grass.

Composting Large Volumes of Grass Clippings

For homeowners with large yards, dealing with massive amounts of grass each mowing session can be daunting. Here are some tips to easily compost large volumes:

  • Build a series of compost bays. This allows you to keep adding fresh grass to empty bays while finished compost cures in others.
  • Utilize forced aeration by placing perforated PVC pipes throughout the pile. The holes facilitate airflow.
  • Turn the pile with a tractor or compost turner if doing it manually becomes too labor-intensive.
  • Limit mowing frequency to let grass grow taller between cuttings. Longer grass means less volume per mowing session.
  • Add a chipper-shredder to your mower deck which chops clippings into fine pieces for faster composting.
  • Mulch mow by leaving clippings on the lawn. This adds nitrogen and organic matter back into the soil.
  • Share some clippings with gardening neighbors who can use them!

Composting Grass in a Pile

Composting grass in a free pile is simple. Follow these steps for fast results:

Select a Site

Find a level, well-draining spot near a water source and not too far from your grass source. Partial shade or sun both work.

Gather Materials

You’ll need:

  • Grass clippings
  • High-carbon browns (leaves, straw, sawdust)
  • Compost accelerators (manure, coffee grounds, comfrey)
  • A pitchfork or aerator for turning
  • A tarp or plastic sheet (optional)

Build the Base

Start by spreading 4-6 inches of browns like straw or twigs on the ground. This creates air flow under the pile.

Or construct a wooden pallet base for the same purpose.

Add Grass and Browns

Toss in a 6 inch layer of shredded grass clippings. Follow with a few inches of browns. Add compost accelerators like manure in thin layers.

Repeat, making layers until the pile reaches at least 3x3x3 feet. Mix materials as you build.

Monitor and Turn the Pile

Check moisture and turn the pile with a pitchfork or compost aerator regularly. Break up any clumps and redistribute material.

Add water if needed while turning. Turn daily or weekly for fastest composting.

Let it Cure

Once items break down and the pile no longer heats up, stop turning. Let it cure undisturbed for 1-2 months while beneficial fungi take over.

Use Your Black Gold

Screen the finished compost to remove any sticks or unsaved grass. Apply 2-3 inches to your garden beds!

Composting Grass in a Bin

Compost bins provide containment and faster heat retention for grass and other waste. Here is the process:

Obtain a Compost Bin

You can buy bins or make your own from wood, wire fencing or recycled pallets. A 3x3x3 foot size is ideal.

Ensure the bin has open slats or holes for aeration. A lid also helps retain heat and moisture.

Start Composting

Follow the same layering method as a compost pile, adding greens, browns, amendments, etc.

Aim for the optimum C:N ratio and particle size. Toss in compost accelerators to speed it up.

Turn the Compost

Open the bin and turn the compost using a pitchfork or compost aerator tool. Turning provides oxygen and redistributes the contents.

Turning weekly is recommended, but turn as often as desired for maximum speed.

Finish and Cure

After the materials break down, stop turning and allow the finished compost to cure for 1-2 months.

Then open the bin and screen the compost to remove any large debris before using in your garden.

Troubleshooting Grass Composting Problems

Composting grass does not always go smoothly. Here are some common problems and how to fix them:

Problem: Bad Smells

Cause: Too much nitrogen (greens), not enough air.

Solution: Add more carbon such as leaves or paper. Turn the pile to increase oxygen.

Problem: Pile not heating up

Cause: Lack of nitrogen, pile too small, or dry conditions.

Solution: Mix in nitrogen sources like food scraps or manure. Add water while turning. Grow the volume to at least 1 cubic yard.

Problem: Grass clumping into mats

Cause: Long, unchopped grass blades tangling together.

Solution: Shred or mow grass into 1 inch or smaller pieces before adding to the pile. Fluff up and turn the compost frequently.

Problem: Slow composting

Cause: Lack of moisture, oxygen and/or proper C:N ratio.

Solution: Monitor conditions and adjust as needed – add browns or greens, water while turning, turn pile, chop into smaller pieces.

Problem: Ammonia smell

Cause: Too much nitrogen from grass.

Solution: Add high-carbon materials like sawdust, cardboard or paper. Turn the pile to release excess ammonia gas.

Using Finished Grass Compost in Your Garden

After your effort, you’ll have dark, crumbly, sweet-smelling compost made from recycled grass clippings! Here are some uses for the finished product:

  • Mix into vegetable and flower garden beds each season to fertilize plants and improve the soil.
  • Make compost tea by steeping compost in water, then use it to water plants or spray on the leaves.
  • Top dress lawns by spreading 1/4 inch of compost over the grass. It will break down slowly and fertilize the lawn.
  • Add 25% compost to potting soil for containers and raised beds to boost nutrients.
  • Use pure compost in seed starting mixes and potting soil for seedlings.
  • Mulch annuals and perennials with a 1-2 inch compost layer to retain moisture and suppress weeds.
  • Spread compost around the base of trees and shrubs to fertilize without risk of burning the roots.

Compost enriched by nitrogen-heavy grass clippings makes plants thrive! It’s worth the small amount of extra effort to compost grass the fast way.

Frequently Asked Questions About Composting Grass

How do I compost large amounts of grass clippings?

For large volumes, build multiple compost piles or bins. Use a tractor or turner to mix the grass. Bury clippings in trenches to decompose. Mulch mow to leave clippings on the lawn.

What is the fastest way to compost grass?

Shred grass into small pieces, maintain the C:N ratio around 30:1, turn and aerate the pile frequently, monitor moisture, and use compost accelerators. Frequent turning and fine particles speed the process.

Do I need to mix grass clippings with other materials?

Yes, mix with browns like dry leaves, paper and straw to balance the high nitrogen content of grass. Straight grass clippings easily become compacted and anaerobic.

How often should you turn compost with grass in it?

Turn grass compost piles or bins at least once per week. Turning daily or even twice daily will greatly speed up decomposition. This introduces oxygen and breaks up clumps.

How can I tell when grass compost is finished?

Finished compost is dark brown, crumbly, sweet smelling, and the original materials are unrecognizable. It should reach internal temperatures of 130-150°F before curing. The pile will no longer reheat after turning.

Can I add too much grass to compost?

Yes, limit high-nitrogen grass to 1/3 or less of the total volume. Excess grass causes odors, compaction and slow breakdown. Mix in adequate carbon-rich materials like leaves or straw to balance grass.

Final Thoughts

Composting grass clippings may require more effort than kitchen scraps, but the reward is a free, nutrient-packed fertilizer for your garden. Follow these guidelines for fast, efficient grass decomposition. With proper techniques, you’ll be making “black gold” out of your mower clippings.