A garbage can composter is a simple, effective DIY bin: drill ventilation and drainage holes in a plastic trash can, add a balanced mix of greens and browns, and turn it regularly for finished compost in a few months.
Turning a plastic trash can into a compost bin is one of the cheapest and most practical ways to turn kitchen scraps and yard waste into usable soil. The whole project takes about an hour of hands-on work, and the materials cost little more than the can itself. Here is exactly how to build one that actually works.
What You Need To Build A Garbage Can Composter
The build starts with a clean, heavy-duty plastic trash can. Most guides recommend a 32 to 55-gallon bin with a tight-fitting lid. You also need a drill with a 1/2-inch to 1-inch spade bit, a bungee cord or locking lid handles if you plan to roll the can, and a spot in the yard where the bin can sit.
Optional but recommended: bricks, cinder blocks, or 2-by-4s to raise the can off the ground. This improves airflow underneath and slows rust on the metal parts of the can’s bottom edge.
Drilling The Right Holes For Air And Drainage
The holes are what make the bin work. Compost microbes need oxygen to break down material, and excess moisture needs an escape route. Drill holes on three surfaces: the sides, the bottom, and the lid.
- Sides: Drill 1/2- to 1-inch holes in rows around the bin, spacing them 3 to 6 inches apart. Avoid the corners to preserve the can’s structural strength. Three or four rows are typical.
- Bottom: Drill about 10 quarter-inch drain holes in the floor of the can so liquid can escape. If the bin sits on soil, these also let worms and soil microbes enter the pile.
- Lid: Drill four to six small holes in the lid for additional airflow. A lid is essential for keeping animals out and moisture in.
If the lid fits loosely, secure it with a bungee cord or locking handles before rolling the can to mix the contents — otherwise the lid can pop off mid-turn.
What To Put Inside And What To Avoid
The secret to fast, odor-free composting is balancing two types of material. Greens provide nitrogen and moisture. Browns provide carbon and structure. Aim for roughly three parts browns to one part greens by volume.
- Greens: Grass clippings, vegetable scraps, coffee grounds, fruit peels, fresh plant trimmings.
- Browns: Dried leaves, shredded newspaper or cardboard, straw, wood chips, sawdust.
- Never add: Meat, dairy, grease, pet waste, or anything treated with pesticides. These attract pests, create odors, or introduce harmful pathogens.
Layer the materials as you fill the can, starting with a thick base of browns to improve drainage. Each time you add kitchen scraps, cover them with about an inch of leaves, soil, or finished compost to keep odors down and discourage flies.
Keeping The Bin Active And Odor-Free
Moisture and air are the two things you manage from here. The material inside should feel like a wrung-out sponge — damp but not dripping. If it gets too wet, add more browns. If it looks dry, mist it lightly with a hose.
Turn the pile every two weeks to keep oxygen flowing through the center. The easiest method on a garbage can composter is to secure the lid and roll the can on its side across the yard. If the lid is not secure, use a pitchfork or a long-handled tool to stir the contents by hand.
Finished compost typically appears in three to six months, depending on temperature, moisture, and how often you turn it. The compost is ready when it looks dark, crumbly, and smells like earth. If you prefer a readymade bin instead of a DIY build, our roundup of the best garbage can composters covers the top pre-built models for getting started faster.
FAQs
Does the can need to sit directly on soil or on blocks?
Either works, but each has a trade-off. Sitting on soil lets worms and microbes enter the pile from below, which helps the composting process. Raising it on bricks or blocks improves drainage and reduces rust on the can’s bottom edge. Choose based on your yard conditions and how long you want the bin to last.
How do I keep animals out of the bin?
A tight-fitting lid is the primary defense. Avoid adding meat, dairy, or oily food scraps, which attract raccoons and rodents. If animals are a persistent problem, secure the lid with a bungee cord or a locking mechanism, and consider placing the bin inside a fenced area.
Why does my compost smell bad?
Bad odors usually mean the pile is too wet, lacks enough browns, or has gone anaerobic. Add more dried leaves or shredded paper to absorb excess moisture, and turn the bin more frequently to reintroduce oxygen. If the smell persists, check that the drain holes in the bottom are not blocked.
References & Sources
- University of Wisconsin Extension. “Can Composter: Do-It-Yourself Compost Bin Instructions.” Details basic bin construction, hole spacing, and material ratios.
- Mississippi Department of Environmental Quality. “DIY Compost Bin Instructions” (PDF). Covers hole patterns, placement on bricks, and animal-deterrence tips.
- Santa Cruz County (California). “Homemade Composter” (PDF). Describes the 3:1 brown-to-green ratio and rolling technique for mixing.