A compost bin is a container that holds kitchen scraps and yard waste while they break down into usable soil

You can build one from materials you likely have on hand—wooden pallets, a plastic storage bin, wire fencing, or even a straightforward pile in a corner of your yard. The bin's job is to contain the decomposing material, keep pests out, and let air and moisture reach the pile evenly. A homemade bin costs little to nothing and works as well as a store-bought one, as long as it lets air in and keeps the pile from spreading across your yard.

The bin does not need to be fancy. What matters is that it holds material in one place, has some way for air to reach the inside, and is sturdy enough not to collapse as the contents settle. You will add brown material (dry leaves, shredded paper, cardboard) and green material (grass clippings, vegetable scraps, coffee grounds) in layers, and the pile will heat up as microbes break it down. In three to six months to a year, depending on how often you turn it and what you add, you will have dark, crumbly compost to mix into garden beds or potted plants.

Key Takeaways

  • The simplest bins are made from wooden pallets wired together, a plastic storage bin with holes drilled in the sides, or a cylinder of wire fencing staked to the ground.
  • Your bin needs drainage holes in the bottom and air holes in the sides so the pile does not become waterlogged or anaerobic.
  • A bin that is roughly 3 feet by 3 feet by 3 feet holds enough material to heat up and decompose faster than a smaller pile.
  • You can speed decomposition by turning the pile every two to four weeks, or let it sit undisturbed for a year if you do not mind waiting longer.

The wooden pallet bin: easiest to build and free if you source pallets locally

Wooden pallets are the fastest route if you can find four of them. Pallets are wooden platforms used to ship goods; many businesses give them away or sell them cheaply. Look for pallets in good condition—no deep rot, no chemical stains. Avoid pallets marked "HT" (heat-treated) if you want to be cautious, though they are safe for compost; never use pallets marked "MB" (methyl bromide), a pesticide.

Stand four pallets on their edges to form a square, with the open side facing out or the solid side facing in—either works. Wire or bolt the corners together so the pallets do not splay outward as the pile settles. Drill or punch holes in the bottom pallet or remove a few boards from the base so water can drain. Line the inside with hardware cloth (a metal mesh) if you want to keep burrowing rodents out, though this is optional. You now have a bin. Start layering brown and green material, and the pile will begin to break down.

The plastic storage bin: works well for small yards or apartment patios

A large plastic storage bin—the kind sold for under-bed storage, roughly 30 to 50 gallons—can become a compost bin with a drill and a few hours of work. Drill holes around all four sides, about 2 inches apart, and drill holes in the bottom for drainage. If the bin has a lid, drill holes in that too so air can reach the top of the pile.

Fill the bin with alternating layers of brown material (shredded paper, cardboard, dry leaves) and green material (vegetable scraps, grass clippings). Keep the pile as moist as a wrung-out sponge. Every week or two, use a pitchfork or shovel to turn the pile by moving material from the outside to the center. A plastic bin heats up quickly because it is small and enclosed, so you can have finished compost in two to three months if you turn it regularly. The downside is that you cannot fit much material in it, so it works best if you have a small household or limited yard space.

The wire cylinder: straightforward to set up and straightforward to turn

Roll a length of wire fencing or hardware cloth into a cylinder about 3 feet tall and 3 feet in diameter, and find the ends with wire or zip ties. Stake the cylinder to the ground with wooden stakes or metal rods so wind does not knock it over. This design is open on all sides, so air reaches the pile easily and turning is straightforward—you straightforward lift the cylinder up and off, then rebuild the pile next to it, moving the material back into the cylinder as you go.

The wire cylinder works best in a yard where you do not mind the pile being visible. It drains well and does not trap moisture the way an enclosed bin can. You will need to turn the pile every two to four weeks to speed decomposition, or let it sit for a year if you prefer a hands-off approach. The main drawback is that rodents and insects can access the pile more easily than they can in an enclosed bin, though this is rarely a serious problem if you avoid adding meat, dairy, or oily foods.

What materials to add and how to layer them

Compost works best when you balance brown material (carbon-rich: dry leaves, shredded paper, cardboard, straw) with green material (nitrogen-rich: grass clippings, vegetable scraps, coffee grounds, plant trimmings). A rough ratio is three parts brown to one part green by volume, though exact ratios are not critical—the pile will decompose even if the balance is off, just more slowly.

Layer the materials as you add them: a few inches of brown, then a few inches of green, then brown again. This helps air and moisture move through the pile evenly. Chop or shred large pieces so they break down faster. Avoid adding meat, fish, dairy, oils, or pet waste, as these attract pests or introduce pathogens. Grass clippings and leaves from your own yard are free and plentiful; vegetable scraps from your kitchen are convenient. Shredded paper and cardboard from packaging are straightforward to collect.

Moisture, temperature, and turning: how to speed up decomposition

The pile should feel as moist as a wrung-out sponge. If it is too dry, decomposition slows; if it is too wet, it becomes anaerobic (oxygen-starved) and smells bad. Water the pile when you add material if the weather has been dry, or cover it loosely with a tarp during heavy rain to prevent waterlogging.

A pile that is at least 3 feet by 3 feet by 3 feet will heat up as microbes break down the material, sometimes reaching 130 to 150 degrees Fahrenheit in the center. This heat speeds decomposition and kills weed seeds and pathogens. You can feel the heat by pushing your hand into the pile—it should feel warm to hot in the middle. If the pile is not heating up, it may be too dry, too wet, or too small; add more material or turn it to introduce air.

Turning the pile every two to four weeks speeds decomposition significantly. Move material from the outside of the pile (where it is cooler and less decomposed) to the center (where it is hotter and breaks down faster). A turned pile can produce finished compost in two to three months. If you do not turn it, the pile will still decompose, but it will take six months to a year. Both approaches work; turning is faster but requires more effort.

When your compost is ready to use

Finished compost is dark brown or black, crumbly, and smells like soil. You should not be able to recognize the original materials—the vegetable scraps and leaves should be completely broken down. If you still see recognizable pieces, the compost is not ready; let it sit longer or turn it again.

Sift finished compost through a screen (a piece of hardware cloth stapled to a wooden frame works well) to remove any large pieces that have not fully decomposed. Mix the finished compost into garden beds at a rate of 1 to 3 inches worked into the top 6 to 8 inches of soil, or use it as a mulch around plants. You can also mix it into potting soil for container plants. Once you have harvested the finished compost, start a new pile in the same bin.

Frequently Asked Questions

Can I compost in an apartment or on a balcony?

Yes, a plastic storage bin with a tight-fitting lid works well on a balcony or in a small space. Drill holes for drainage and air, keep the pile moist but not wet, and turn it every week or two. A small bin will not smell if you balance brown and green material and avoid meat and dairy. You will have finished compost in two to three months.

What should I do if my compost pile smells bad?

A bad smell usually means the pile is too wet or too dense, trapping oxygen. Turn the pile to introduce air, and add dry brown material like shredded paper or leaves. If it smells like ammonia, you have too much green material; add more brown. If it smells like rotten eggs, it is anaerobic; turn it when ready and let it dry out slightly.

Do I need a lid on my compost bin?

A lid is optional. It keeps rain out and helps retain heat, which speeds decomposition, but it also traps moisture and can make the pile anaerobic if not ventilated. A loose-fitting lid or a tarp that you remove regularly works better than a sealed lid. Many successful bins have no lid at all.

Can I add diseased plants or weeds to my compost?

Diseased plants can spread pathogens if your pile does not heat up enough to kill them. Weeds with seeds will survive unless your pile reaches at least 130 degrees Fahrenheit in the center. If you turn your pile regularly and it heats up, you can add both; if you let it sit undisturbed, it is safer to leave them out.

How long does it take to get finished compost?

If you turn the pile every two to four weeks and keep it moist and balanced, you can have finished compost in two to three months. If you do not turn it, expect six months to a year. Temperature, pile size, and what you add all affect the timeline. A smaller pile or one in a cold climate will take longer.