Start with the right mix of materials

Compost soil forms when you layer brown materials (dry leaves, shredded paper, cardboard, wood chips) with green materials (grass clippings, vegetable scraps, coffee grounds, plant trimmings). The browns provide carbon; the greens provide nitrogen. Both are necessary. A working pile needs roughly three parts brown to one part green by volume, though the exact ratio is forgiving—compost will form even if you're off.

Start by choosing a location that gets partial sun and has good drainage. A shaded spot works too, but sun speeds decomposition. Avoid placing your pile directly against a wooden fence or house, since moisture and insects can damage the structure. A bin made from wood pallets, wire fencing, or plastic works well, but you can also pile materials directly on bare ground.

Chop or shred larger materials before adding them. Smaller pieces decompose faster because microbes have more surface area to work with. A leaf shredder or lawn mower run over a pile of leaves takes minutes and cuts decomposition time significantly.

Key Takeaways

  • Layer brown materials (leaves, cardboard, wood chips) with green materials (food scraps, grass clippings) in roughly a 3-to-1 ratio by volume.
  • Keep the pile as moist as a wrung-out sponge—wet enough that water drips out when you squeeze it, but not waterlogged.
  • Turn the pile every one to two weeks with a pitchfork or shovel to speed decomposition; finished compost appears dark brown and crumbly in 2 to 6 months.
  • Avoid adding meat, dairy, oils, or diseased plants, which attract pests or spread plant illness.
  • Finished compost is ready to use when you cannot identify the original materials and it smells earthy, not rotten.

Water and moisture management

The pile must stay moist but not soggy. Squeeze a handful of compost: water should drip out slowly, but not stream. If it's dry, the microbes slow down and decomposition stalls. If it's waterlogged, the pile becomes anaerobic (oxygen-starved) and smells like rotten eggs or ammonia.

In dry weather, water the pile every few days with a hose, soaking it thoroughly. In rainy climates, you may need to cover the top with a tarp or wooden lid to prevent it from becoming oversaturated. Check moisture by digging into the center of the pile—the inside should feel damp even if the surface looks dry.

Turning the pile for faster results

Turning the pile every one to two weeks speeds decomposition from several months to as little as 6 to 8 weeks. Use a pitchfork or shovel to move material from the outside edges (where it's cooler) to the center (where heat is highest). This redistributes microbes, adds oxygen, and breaks up compacted material.

If you don't turn the pile, compost will still form—it just takes longer, usually 6 to 12 months. This method, called cold composting, requires less work but produces finished compost more slowly. Turning creates hot composting, where the pile heats up to 130–150°F as microbes work intensely, killing weed seeds and pathogens in the process.

When you turn, aim for a pile at least 3 feet tall and 3 feet wide. Smaller piles don't retain heat well and decompose more slowly. If your pile is too small, wait until you've added more material before turning.

What to add and what to avoid

Safe to add: fruit and vegetable scraps, coffee grounds and tea bags, crushed eggshells, grass clippings, leaves, shredded newspaper and cardboard, straw, hay, wood chips, plant trimmings, and manure from herbivores (horses, cows, rabbits). Avoid: meat, fish, bones, dairy, oils, fats, diseased plants, weeds with seeds, pet waste, and glossy or colored paper.

Meat and dairy attract rats and raccoons and create foul odors. Diseased plants spread illness to your garden. Weeds with mature seeds may survive the pile and sprout in your finished compost. If you're unsure about an item, leave it out—the safest approach is to stick with plant-based materials and herbivore manure.

Recognizing finished compost

Finished compost is dark brown or black, crumbly, and smells earthy—like forest soil after rain. You should not be able to identify the original materials. If you still see recognizable leaves, food scraps, or cardboard, the pile needs more time.

Sift finished compost through a 1/2-inch screen (hardware cloth stapled to a wooden frame) to remove large chunks and create a uniform texture. Store finished compost in bags or bins in a dry location. It keeps indefinitely but loses some nutrients over time, so use it within a year for best results.

Troubleshooting common problems

Pile smells like ammonia or rotten eggs: This means the pile is too wet or has too much green material. Turn it, add brown material, and reduce watering. Ammonia smell usually clears within a few days of turning.

Pile is not heating up or decomposing: The pile is too small, too dry, or has too much brown material. Add more green material, water it, and turn it. A pile smaller than 3 feet on each side may never heat up enough for hot composting.

Flies or gnats around the pile: You likely added meat, dairy, or oil. Cover food scraps with a layer of brown material (leaves or cardboard) to reduce odor and flies. If the problem persists, stop adding food scraps temporarily and turn the pile daily for a week.

Pile is attracting rats or raccoons: Do not add meat, dairy, or oils. Use a fully enclosed bin with a tight-fitting lid rather than an open pile. Bury food scraps under at least 8 inches of brown material.

Using your finished compost

Mix finished compost into garden beds at a rate of 1 to 3 inches worked into the top 6 to 8 inches of soil. Use it as mulch around trees and shrubs, or blend it into potting soil for container plants (one part compost to two parts store-bought potting mix). Compost improves soil structure, increases water retention, and feeds plants slowly over time.

You do not need to wait for a full batch to finish before starting a new pile. Many gardeners maintain two or three piles at different stages—one actively being filled, one being turned, and one finishing. This way, you always have finished compost ready to use.

Frequently Asked Questions

How long does it take to make compost?

Cold composting (no turning) takes 6 to 12 months. Hot composting (turning every one to two weeks) takes 2 to 6 months. Speed depends on pile size, material type, moisture, temperature, and how often you turn it. Smaller pieces decompose faster than whole leaves or branches.

Can I make compost in an apartment or small space?

Yes. Use a small bin (12 to 18 inches tall) on a balcony or under a sink. Add only food scraps and shredded paper, no grass or yard waste. Bury scraps under brown material to reduce odor and pests. Finished compost takes longer in a small bin—usually 3 to 6 months—but it works.

Do I need to add compost starter or microbes?

No. Soil, leaves, and finished compost already contain billions of microbes. Adding a commercial starter is unnecessary and does not speed decomposition noticeably. Save your money and let natural microbes do the work.

What temperature kills weed seeds and pathogens?

A hot compost pile reaches 130–150°F at the center, which kills most weed seeds and plant pathogens. Cold composting does not get hot enough to reliably kill seeds, so avoid adding weeds with mature seed heads to a cold pile. If you use cold compost in a garden, pull weeds as they appear.

Can I compost sawdust or wood shavings?

Yes, but use only untreated wood. Sawdust from pressure-treated lumber contains toxic chemicals. Untreated sawdust and wood shavings are excellent brown material and decompose slowly, so they improve soil structure for years. Mix them with green material and turn the pile regularly.