Start with the right location and container
A compost pile works best in a spot that gets partial sun—at least a few hours a day—and is reasonably level. The pile needs air circulation around it, so place it away from the house foundation and dense shrubs. You can compost in an open pile on bare ground, in a wooden bin you build yourself, in a wire cylinder, or in a plastic bin with a lid. The container choice depends on your space and how much you want to contain the pile.
If you use an open pile, the ground contact helps with drainage and lets organisms move in and out. If you build or buy a bin, make sure it has some way for air to reach the pile—either gaps in the sides or a removable lid. A bin roughly three feet by three feet by three feet is large enough for the pile to heat up properly, which speeds decomposition.
Layer brown and green materials in the right ratio
Brown materials are dry and carbon-rich: dry leaves, shredded paper, cardboard, straw, and wood chips. Green materials are wet and nitrogen-rich: grass clippings, vegetable scraps, coffee grounds, and fresh plant trimmings. The pile decomposes fastest when you mix roughly three parts brown to one part green by volume. This ratio keeps the pile from becoming too wet and smelly while giving microbes enough nitrogen to work with.
Start by laying down a layer of brown material about six inches thick on the ground or bin bottom. This creates air pockets and drainage. Then add a layer of green material about two inches thick. Repeat this pattern—brown, then green—until your pile is at least three feet tall. If you have a lot of one material, you can add it all at once and balance it with the other material later.
Key Takeaways
- Place your pile in partial sun on level ground with air circulation, either in an open pile or a bin at least three feet square.
- Layer brown materials (leaves, cardboard, straw) and green materials (grass, food scraps, plant trimmings) in a three-to-one ratio by volume.
- Keep the pile as moist as a wrung-out sponge by watering it when the top feels dry, and turn it every one to two weeks to speed decomposition.
- Finished compost is dark, crumbly, and smells earthy; it takes two to six months depending on how often you turn the pile and how small you chop the materials.
Water and turn the pile to keep it active
A working compost pile needs moisture to break down, but not so much that it becomes waterlogged. Check the pile by squeezing a handful of material from the middle. It should feel as moist as a wrung-out sponge. If it is dry, water it until that moisture level returns. If it is soggy, add more brown material and turn the pile to let air in.
Turning the pile—moving material from the outside to the center—speeds up decomposition by introducing oxygen and mixing materials evenly. Turn the pile every one to two weeks if you want finished compost in two to three months. If you turn it less often or not at all, decomposition takes longer, usually four to six months or more. You do not have to turn it at all; the pile will eventually break down on its own, just more slowly.
Recognize what you can and cannot compost
Safe to compost: vegetable and fruit scraps, coffee grounds and tea bags, grass clippings, leaves, straw, hay, shredded paper and cardboard, wood chips, plant trimmings, and eggshells. These materials break down without creating problems.
Do not compost: meat, fish, bones, dairy, oils, fats, pet waste, diseased plants, weeds with seeds, or glossy or colored paper. Meat and dairy attract rodents and create odor. Pet waste can harbor pathogens. Diseased plants and seeded weeds spread problems to your garden. Glossy paper often contains chemicals that do not belong in soil.
Know when your compost is ready to use
Finished compost is dark brown or black, crumbly, and smells earthy—not sour or ammonia-like. You should not be able to recognize most of the materials you put in. If you see chunks of leaves or wood, the pile is not ready yet. Sift finished compost through a half-inch screen or your hands to remove larger pieces, which you can return to a new pile.
You can use finished compost in garden beds, mixed into potting soil, spread as mulch around plants, or worked into the top few inches of lawn. It improves soil structure, adds nutrients, and helps soil hold water. There is no risk of over-explore compost the way there is with chemical fertilizer.
Troubleshoot common compost problems
The pile smells like ammonia or rotten eggs: This means too much green material or not enough air. Add brown material and turn the pile. The pile is wet and slimy: Add brown material and turn it to dry it out. The pile is not heating up or breaking down: It may be too small, too dry, or have too much brown material. Make sure it is at least three feet tall, water it, and add more green material.
Rodents or insects are visible: Do not compost meat, dairy, or oils, which attract them. Bury food scraps under brown material instead of leaving them on top. If you have a bin, make sure the bottom is sealed or sits on hardware cloth. The pile is taking too long: Chop materials into smaller pieces before adding them, turn the pile more often, and keep the moisture and brown-to-green ratio balanced.
Frequently Asked Questions
Can I compost in winter?
Yes, but decomposition slows dramatically in cold weather because microbes work slower. A pile that breaks down in three months in summer may take six months or longer in winter. You can keep adding materials to the pile year-round; they will sit until spring warmth speeds things up.
Do I need to add compost starter or microbes?
No. Soil, leaves, and finished compost already contain all the microbes you need. Commercial starters are not necessary. If you want to speed things up, add a shovel of finished compost or garden soil to your new pile, which introduces active microbes.
What if my pile smells bad?
Bad smell usually means too much green material, not enough air, or too much moisture. Add brown material, turn the pile to introduce oxygen, and let it dry out a bit. A healthy pile should smell earthy, not sour or like rotten eggs.
Can I compost sawdust or wood shavings?
Yes, but use only untreated wood. Sawdust from pressure-treated lumber contains chemicals that should not go in soil. Untreated sawdust and wood shavings are brown material and break down slowly, so chop them fine and mix them well with green material.
How do I know if my compost has finished if I never turned it?
Wait until the original materials are no longer recognizable and the pile has shrunk to about half its original size. This usually takes four to six months. The material should be dark, crumbly, and smell earthy. If you are unsure, wait another month.