Build a Basic Composter in an Afternoon

You can make a working composter from a plastic storage bin, wooden pallets, or a wire cylinder—all materials you may already have or can find cheaply. The simplest version takes about an hour to assemble and costs nothing if you use what's on hand. A bin composter works fastest for small kitchens; a pallet box suits yards with more space; a wire tumbler works well if you want to turn compost frequently.

The core idea is the same for all three: create a container that holds brown material (dry leaves, shredded paper) and green material (food scraps, grass clippings) while letting air and moisture move through. You don't need special tools, special fasteners, or a kit. You need a container, drainage, and air holes.

Key Takeaways

  • A plastic bin composter is ready to use in one hour and works in small spaces, but fills up faster than larger designs.
  • A wooden pallet composter holds more material and costs little if you find free pallets, but takes two to three hours to build.
  • All composters need drainage holes at the bottom and air holes on the sides to prevent rot and bad smells.
  • Start with a layer of brown material (leaves, cardboard), add green material (food scraps, grass), then alternate layers as you add waste.
  • A finished composter should smell earthy, not sour or rotten—if it smells bad, add more brown material and turn it more often.

The Plastic Bin Composter: Fastest to Build

Take a 20- to 30-gallon plastic storage bin with a lid. Using a drill with a quarter-inch bit, drill holes in a grid pattern across the bottom—space them about 4 inches apart. Then drill holes around all four sides, about 6 inches from the bottom, in the same grid pattern. These holes let air reach the compost and let liquid drain out. Drill a few holes in the lid as well for ventilation.

Place the bin on a tray or in a shallow pan to catch drainage. Add a 4-inch layer of brown material (shredded newspaper, dry leaves, or cardboard torn into strips) to the bottom. Compress it lightly with your hands. Add a 4-inch layer of green material (vegetable scraps, coffee grounds, grass clippings). Sprinkle the green layer lightly with water until it feels like a wrung-out sponge. Repeat layers until the bin is three-quarters full. Put the lid on.

Every week or two, lift the bin and shake it side to side for 30 seconds to turn the compost without opening it. In four to six months, the bottom layer will turn dark and crumbly. Finished compost is ready to use in gardens or potted plants.

The Wooden Pallet Composter: Largest Capacity

Find four wooden pallets of the same size (often free from warehouses, garden centers, or online marketplaces). Lay them flat on the ground in a square. Stand them up on their edges so the square is about 3 feet by 3 feet. Attach the corners together using 3-inch wood screws—two screws per corner, one near the top and one near the bottom. A power drill makes this faster, but a hand screwdriver works too.

For the bottom, lay cardboard or landscape fabric across the ground inside the square. This keeps the compost from spilling out while still letting water drain. You can skip this step if you don't mind some material falling through the gaps.

For the front, you have two choices: attach a fourth pallet as a removable door (use bolts through the corners so you can unbolt it to pull finished compost out), or leave the front open and shovel from the side. An open front is simpler to build but messier to use.

Add layers the same way as the bin: 4 inches of brown, 4 inches of green, water lightly, repeat. This size holds enough material to heat up and break down faster than a bin. Turn it every two weeks by moving material from one corner to the next using a pitchfork. Finished compost appears in three to four months.

The Wire Cylinder Composter: Easiest to Turn

Buy a roll of wire fencing (chicken wire or hardware cloth, 3 to 4 feet tall) from a hardware store, or use leftover fencing. Form it into a cylinder about 3 feet across and find the overlapping ends with zip ties or wire. Stand it upright on the ground.

Line the inside with cardboard or newspaper to slow material from falling through the gaps. Add layers of brown and green material the same way as the other designs. Because the cylinder is open on all sides, air reaches the compost easily, so it breaks down quickly.

To turn this composter, lift the cylinder straight up and set it beside the pile. Use a pitchfork to move the pile back into the cylinder. This mixes the material thoroughly and speeds decomposition. Turn it weekly if you want finished compost in six to eight weeks, or every two weeks for a slower process.

Layering and Moisture: The Two Things That Matter Most

Compost works when brown and green material are balanced. Brown material (leaves, shredded paper, cardboard, straw) is dry and carbon-rich. Green material (vegetable scraps, fruit peels, grass clippings, coffee grounds) is wet and nitrogen-rich. Aim for roughly twice as much brown as green by volume. If your compost smells sour or slimy, you have too much green—add shredded leaves or cardboard.

Moisture should feel like a wrung-out sponge: damp but not dripping. If the pile is too dry, it breaks down slowly. If it's too wet, it smells rotten and attracts flies. After adding material, sprinkle it lightly with water. If rain is heavy, cover the composter with a tarp or lid to prevent waterlogging.

Avoid meat, dairy, oils, and pet waste—these attract pests and create odors. Stick to vegetable and fruit scraps, coffee grounds, tea bags, eggshells, grass clippings, leaves, and shredded paper.

Common Mistakes and How to Fix Them

Smell like rotten eggs or ammonia: Too much green material or not enough air. Add a large handful of shredded leaves or cardboard, then turn the pile. Drill more air holes if the container is solid plastic.

Pile is wet and slimy: Too much moisture or poor drainage. Check that drainage holes aren't blocked. Add brown material and turn the pile to let it dry out. If the composter is in a rainy spot, move it or cover it during heavy rain.

Nothing is breaking down after three months: The pile is too cold (happens in winter), too dry, or too compact. Turn it thoroughly to add air. Add green material to heat it up. In winter, composting slows dramatically—this is normal.

Flies or fruit flies around the composter: Food scraps are exposed. Bury new scraps under 4 inches of brown material. Make sure the lid or cover fits snugly. If flies are already there, turn the pile and cover it tightly for a week.

When Your Composter Is Ready to Harvest

Finished compost looks dark brown or black, crumbly, and earthy. You should not see the original materials—leaves, scraps, and paper should be unrecognizable. It should smell like soil, not like the food that went in.

For a bin composter, stop adding new material and let it sit for two weeks. Then dump the whole bin onto a tarp and sift out the finished compost from the bottom. Return unfinished material to the bin to keep composting.

For a pallet or wire composter, pull finished compost from the bottom using a shovel or pitchfork. You can harvest while still adding new material to the top—just work carefully around the sides.

Use finished compost in vegetable gardens, flower beds, potted plants, or as a top dressing on lawns. Mix it into garden soil at a ratio of one part compost to three parts soil, or use it straight in containers.

Frequently Asked Questions

Do I need to buy a composter or can I really make one?

You can make a working composter from materials you likely have at home—a plastic bin, wooden pallets, or wire fencing. The only tool you might need to buy is a drill for making air holes, which costs $30 to $50 if you don't own one. A homemade composter works as well as a store-bought one.

What's the difference between hot and cold composting?

Hot composting means turning the pile weekly and keeping it moist and balanced—it finishes in two to three months but requires more work. Cold composting means adding material and leaving it alone—it takes six to twelve months but needs almost no effort. A homemade composter can do either one depending on how often you turn it.

Can I compost in winter?

Yes, but it slows down dramatically. Microbes work slowly in cold temperatures. Keep adding material and turning occasionally if you want to speed it up. In spring, the pile will heat up and decomposition will accelerate. Many people stop adding to their composter in winter and harvest finished material in spring.

What if I don't have space for a composter?

A small plastic bin composter fits under a kitchen sink or on a balcony and holds enough scraps for one or two people. If you have no outdoor space, you can also keep a sealed container of scraps in the freezer and take them to a community garden or farmers market compost drop-off when it's full.

How do I know if my composter has enough air?

Smell the pile. If it smells earthy, air is reaching it. If it smells sour, slimy, or like ammonia, it needs more air. Turn it thoroughly or drill more holes. A working composter should never smell bad—bad smell is a sign something needs fixing.