Compost forms when bacteria and fungi break down kitchen scraps and yard waste in the right conditions

Making compost is a process of layering brown materials (dry leaves, shredded paper, cardboard) with green materials (food scraps, grass clippings, plant trimmings), keeping the pile moist like a wrung-out sponge, and turning it every few days. The microorganisms already present on these materials do the work—you are just creating the conditions they need. A properly built pile reaches an internal temperature of 130 to 150 degrees Fahrenheit within a week, which kills weed seeds and pathogens, and breaks down into dark, crumbly compost in three to four weeks.

You do not need special equipment or a purchased bin. A straightforward pile on bare ground works, as does a wire cage, wooden box, or plastic storage bin with holes drilled in the bottom and sides. The key is having enough material to build a pile at least 3 feet wide, 3 feet tall, and 3 feet deep—smaller piles do not heat up enough to decompose quickly.

Key Takeaways

  • Layer brown materials (leaves, paper) and green materials (food scraps, grass) in roughly equal amounts by volume, starting with a brown layer on the ground.
  • Keep the pile as moist as a wrung-out sponge; if it smells like ammonia or rotten eggs, it is too wet or has too many greens, so add brown materials and turn it.
  • Turn the pile every two to three days by moving material from the outside edges to the center, where it is hottest and decomposes fastest.
  • Finished compost is dark brown, crumbly, and smells like soil; it takes three to four weeks with regular turning, or two to three months if you leave it undisturbed.
  • Do not add meat, dairy, oils, diseased plants, or pet waste, as these either attract pests or introduce pathogens that home compost does not get hot enough to kill.

Gather Your Materials Before You Start

Collect brown materials first: dry leaves (shred them by running a lawn mower over them), shredded newspaper or cardboard, straw, or wood chips. You need roughly as much brown material by volume as green material. Green materials include vegetable and fruit scraps (no oils or meat), grass clippings, plant trimmings, coffee grounds with filters, and tea bags. If you do not have enough of either type on hand, start with what you have and add more as it becomes available—the pile will still work, just more slowly.

Chop or shred everything into pieces smaller than 1 inch. Smaller pieces have more surface area for microorganisms to work on, which speeds decomposition. A kitchen knife works for soft scraps; a shovel or lawn mower handles leaves and grass. Do not worry about being perfect—rough chunks will still break down, just over a longer time.

Build Your Pile in Layers

Start on bare ground or in your bin with a 4-inch layer of brown material. This base layer lets air flow underneath. Add a 4-inch layer of green material on top, then alternate brown and green layers until your pile is at least 3 feet tall. Finish with a brown layer on top—this reduces odor and keeps flies away from the green materials underneath.

Water each layer as you build so the whole pile is moist but not soggy. Squeeze a handful of material from the middle: water should not drip out, but your hand should feel damp. If the pile is too dry, microorganisms cannot work; if it is too wet, it becomes anaerobic (without oxygen) and smells foul.

Turn the Pile Every Two to Three Days

Use a garden fork or shovel to move material from the outside edges of the pile to the center. The center is hottest and decomposes fastest, so moving cooler outside material to the center speeds the whole process. Turning also adds oxygen, which aerobic bacteria need to work efficiently. Each time you turn, the pile will heat up again within a day or two—you will see steam rising from the center on cool mornings.

If you cannot turn the pile regularly, it will still compost, just over two to three months instead of three to four weeks. Some people build a static pile and leave it alone; it works, but takes longer because the material at the edges stays cool and decomposes slowly.

Watch for Common Problems and Fix Them

If your pile smells like ammonia or rotten eggs, it has too much nitrogen (too many greens) or is too wet. Add brown materials—shredded leaves or cardboard—and turn the pile to add air. If it smells like vinegar, it is anaerobic; turn it and add brown materials to improve air flow.

If the pile is not heating up or breaking down, it is either too small, too dry, or has too much brown material. Add more green materials, water it, and turn it. If you see fruit flies or other pests, you likely added meat, dairy, or oily food scraps. Bury any remaining scraps deeper in the pile and cover the top with a thick layer of brown material.

If the pile shrinks but does not seem to be breaking down, the material may be too coarse. Chop it finer and turn it more often. Woody material like wood chips or thick branches takes much longer to break down than softer plant material.

Recognize When Your Compost Is Ready

Finished compost is dark brown or black, crumbly, and smells like rich soil or forest floor. You should not be able to identify the original materials—everything should look uniform. If you can still see leaves or food scraps, it is not ready yet; turn it and wait another week or two.

Use a finished compost thermometer or your hand to check the center of the pile: if it is no longer hot to the touch and the material is dark and crumbly, it is done. Sift it through a 1/2-inch screen (hardware cloth stapled to a wooden frame) to remove any large pieces that have not fully broken down; return those pieces to a new pile.

Use Your Finished Compost in the Garden

Mix finished compost into garden beds at a rate of 1 to 2 inches worked into the top 6 to 8 inches of soil. Use it as mulch around plants, blend it into potting soil for containers, or top-dress lawns with a thin layer. Compost improves soil structure, adds nutrients slowly over time, and helps soil hold water.

Store finished compost in a dry place if you are not using it right away. It will not break down further once it is cool and dark, but it will dry out if left exposed to sun and rain. A covered bin or pile under a tarp keeps it ready to use whenever you need it.

Frequently Asked Questions

Can I use a closed plastic bin instead of an open pile?

Yes. Drill holes in the bottom and sides for air flow, layer materials the same way, and turn it by rotating the bin or moving material inside with a shovel. Closed bins heat up faster and keep out pests and rain, but they hold less material and are harder to turn. They work well for small households or apartments.

How often do I really need to turn the pile?

Every two to three days gives you finished compost in three to four weeks. Turning once a week takes six to eight weeks. If you do not turn at all, it takes two to three months but still works—you are just waiting for the pile to decompose on its own instead of speeding it up with air and mixing.

What if I do not have enough brown materials?

Shred newspaper, cardboard, or paper bags to use as brown material. Avoid glossy or colored paper. If you still do not have enough, build a smaller pile or add brown materials as they become available. The pile will work with fewer browns; it just may smell or attract pests until you balance it out.

Can I add weeds or diseased plants?

Weeds are fine if they have not gone to seed. Diseased plants are risky because home compost piles often do not stay hot enough long enough to kill all pathogens. If you add diseased material, turn the pile frequently and make sure it reaches at least 130 degrees Fahrenheit in the center for at least three days.

Why does my compost smell bad?

Bad smells mean the pile is anaerobic (without enough oxygen) or has too much nitrogen. Turn it when ready to add air, add brown materials like leaves or cardboard, and check that it is not waterlogged. A healthy pile should smell earthy or like forest floor, not sour or rotten.