Composting Yard Waste: Leaves, Clippings and What to Leave Out

Fall leaves, grass clippings and garden trimmings make up a large share of what many households put out for collection. Most of it can become compost in your own yard, which saves bags and trips and gives you a free soil improver for lawns, beds and containers.

Composting yard waste is not complicated. It comes down to mixing the right materials, keeping them damp and letting air in.

Quick answer

• Mix browns and greens. Browns are dry, carbon-rich materials such as leaves and straw. Greens are fresh, nitrogen-rich materials such as grass clippings and plant trimmings. A common starting point is two to three parts browns to one part greens by volume.
• Keep it as damp as a wrung-out sponge.
• Add air by turning the pile or building it loosely.
• Size matters: a pile of about 3 feet by 3 feet by 3 feet heats up and breaks down faster than a small heap.
• Leave out diseased plants, seeding weeds, invasive plants, pet waste and clippings treated with persistent herbicides.

Before composting: leave clippings on the lawn

The easiest way to deal with grass clippings is not to collect them. Short clippings from regular mowing break down quickly and return nutrients to the soil. Follow the one-third rule in our guide on how often to mow your lawn and let the mower spread them. Compost the clippings you do collect, such as when the grass was too long or wet.

Browns and greens

Browns (carbon)	Greens (nitrogen)
Dry leaves	Fresh grass clippings
Straw	Green plant trimmings and spent annuals
Shredded paper and plain cardboard	Vegetable and fruit scraps
Small twigs and wood chips	Coffee grounds
Pine needles (in moderation)	Fresh weeds without seeds

Too many greens, especially thick layers of fresh grass, make a wet, smelly, slimy pile. Too many browns make a dry pile that sits for a year or more without doing much. If the pile smells, add browns and turn it. If nothing is happening, add greens and water.

Fall gives you a surplus of browns. Store bags of dry leaves next to the bin and add some each time you add fresh clippings or kitchen scraps the following spring and summer.

Moisture and air

Composting organisms need both water and oxygen.

• Moisture: squeeze a handful from the middle of the pile. It should feel damp, with no more than a drop or two of water. Water dry layers as you build the pile.
• Air: turn the pile with a garden fork every week or few weeks, or build it with coarse material at the bottom so air can move through. A tumbler turns more easily than a pile.

Hot vs cold composting

Hot composting: build a large pile at once with a good mix of browns and greens, keep it moist and turn it regularly. The center can heat to roughly 130 to 160°F, which speeds decomposition and kills many weed seeds and plant pathogens. Finished compost can be ready in a few months.

Cold composting: add material as you get it and let it sit. It takes longer, often a year or more, and does not get hot enough to kill weed seeds reliably, but it needs very little work.

Most home piles fall somewhere in between.

Bin types

Type	Advantages	Drawbacks
Open pile	Free; easy to turn	Untidy; dries out or gets soggy more easily
Wire or mesh bin	Cheap; good airflow	Can dry out; less tidy
Wooden pallet or slatted bin	Holds a large volume; easy to build	Wood eventually rots
Three-bin system	One bin filling, one cooking, one finished	Takes space and materials
Plastic enclosed bin	Tidy; keeps moisture in	Harder to turn; can get too wet
Tumbler	Easy to turn; neat	Limited capacity; full loads are heavy

Place the bin on bare soil in a convenient spot, with access for a wheelbarrow and a hose. Check any local rules or homeowners’ association restrictions on bins and setbacks from property lines.

Leaves and leaf mold

Whole leaves mat together and break down slowly. Shred them first by running a mower over them, which also makes them easier to store. Our fall yard cleanup checklist covers mulching leaves into the lawn when there are only a few.

Leaf mold is a simple alternative to compost. Pile shredded leaves in a wire enclosure or in bags with a few holes, keep them damp and leave them for a year or two. The result is a crumbly, dark material that holds moisture well and is excellent as mulch or mixed into potting soil.

What to leave out

• Diseased plants and plants with pests, unless your pile reliably gets hot.
• Weeds with seeds or roots that resprout, such as bindweed or quackgrass.
• Invasive plants. Follow local disposal guidance so you do not spread them.
• Clippings treated with persistent herbicides. Some lawn and pasture herbicides break down very slowly and can survive composting, then damage vegetables and flowers when the compost is used. Read the herbicide label for compost and clipping restrictions.
• Pet waste, meat, fish, dairy, oils and greasy food. These attract pests and can carry pathogens.
• Treated or painted wood, coal ash and charcoal briquette ash.
• Large branches that will take years to break down. Chip them for paths instead.

When the compost is ready

Finished compost is dark and crumbly, smells earthy, and the original materials are mostly unrecognizable. Screen out larger pieces and return them to the pile.

Using compost on lawns and gardens

• Lawns: spread a thin layer, about a quarter inch, over the lawn and rake it into the grass, especially after aerating and overseeding. See our guides to core vs. spike aeration and how to overseed a lawn.
• Beds and borders: work it into the soil before planting or use it as mulch around plants. For vegetables, see our raised garden bed guide.
• Containers: mix a portion into potting mix.
• New lawns: incorporate compost into the topsoil before seeding.

Compost improves soil structure and adds nutrients, but it is not a complete replacement for fertilizer in every situation. A soil test shows what your lawn actually needs; our guide on when to fertilize your lawn explains how to read one.

Common problems

Problem	Likely cause	Fix
Bad smell	Too wet or too many greens	Add browns and turn
Nothing happening	Too dry, too many browns, too small	Add water and greens; build a bigger pile
Pests	Food scraps exposed	Bury scraps in the center; avoid meat and dairy
Flies	Exposed greens	Cover fresh material with browns

FAQ

Can I compost grass clippings by themselves? They tend to compact and turn slimy. Mix them with dry leaves or other browns.

Do I need a compost starter? Usually not. A shovel of garden soil or finished compost introduces the organisms you need.

How long does it take? From a few months for a well-managed hot pile to a year or more for a cold pile.

Can I compost in winter? Activity slows in cold weather, but you can keep adding materials. The pile will become active again in spring.