How to Compost in a Trash Can | DIY Bin That Works

Composting in a trash can works by drilling airflow holes into a heavy-duty 32-55 gallon plastic bin, layering brown and green materials at a 2:1 ratio, and rolling the can every two weeks to produce finished compost in 3-6 months.

A garbage can composter costs next to nothing if you own a spare bin—or about $15 to $30 for a new 32-gallon can—and turns kitchen scraps and yard waste into dark, crumbly soil conditioner without a store-bought tumbler. The trade-off is manual effort: you roll a 50-pound can on its side or stir with a tool every couple of weeks. If you want a setup you can spin with one hand, our tested roundup of the best compost trash cans covers tumblers that do the turning for you.

Here is how to build and run a trash-can composter the right way—no fancy gear required.

Choosing the Right Can and Tools

A 32- to 55-gallon heavy-duty plastic garbage can with a tight-fitting lid works best. Metal cans rust fast and hold too much heat, which can kill the microorganisms doing the work. You also need a drill with a 3/4-inch bit for the side and bottom holes, plus a 1/4-inch to 1/2-inch bit for the lid.

What you need for this project:

• Heavy-duty plastic trash can (32–55 gallon, locking lid preferred)
• Drill with 3/4-inch and 1/4-inch to 1/2-inch drill bits
• Two cinder blocks or three bricks to elevate the can
• Optional: a 2-foot PVC pipe drilled with holes for internal aeration, or a bulb auger for stirring
• Two bungee cords if your lid does not lock securely

Drilling and Setting Up the Bin

Drill 3/4-inch holes spaced 4–6 inches apart across the entire bottom of the can. On the sides, space the same 3/4-inch holes 8–10 inches apart in staggered rows. Drill 1/4-inch to 1/2-inch holes on the lid for ventilation. Set the can on two cinder blocks or three bricks so air circulates underneath and excess moisture drains freely.

Place the bin in a convenient spot with a hose or spigot nearby. Sun or shade both work—sun speeds decomposition but requires more frequent watering in dry weather. Cold winters will slow the process considerably, so expect longer wait times if you start in late fall.

Layering the Right Materials

The secret to compost that does not stink or turn slimy is the brown-to-green ratio. Browns are carbon-rich (dried leaves, straw, shredded paper, wood chips). Greens are nitrogen-rich (grass clippings, vegetable scraps, coffee grounds). Aim for roughly 2 to 3 parts browns for every 1 part greens by volume.

How to fill the can in layers:

• Start with 4–6 inches of bulky browns at the bottom for drainage.
• Alternate 3-inch layers of greens and 6-inch layers of browns on top.
• Chop kitchen scraps to 1–2 inch pieces—smaller material breaks down faster.
• Water each layer until the whole pile feels like a wrung-out sponge.
• Fill the can no more than three-quarters full so there is room for mixing.

Keep these items out of the bin: meat, dairy, animal waste, human waste, diseased plants, invasive weeds, large sticks, and yard waste treated with chemical pesticides or herbicides.

Turning, Moisture, and Harvesting

Secure the lid (bungee cords help if the fit is loose) and roll the can across the yard every two weeks—four or five full rotations usually do the job. If rolling is too heavy, stir with an auger or a long PVC pipe instead. The pile should stay as damp as a wrung-out sponge; add water if it feels dry, or add more browns if it is soggy.

Finished compost takes 3–6 months in warm weather. It is ready when the pile shrinks to about half its original volume and the material looks dark, crumbly, and smells like earth. Screen out any large chunks and let the compost cure for 4 weeks before using it on garden beds if some pieces are still recognizable.

Leachate—liquid that drains from the bottom—can soak into the ground below the can. If you need to contain it, set a shallow catch pan or drip tray under the blocks.

FAQs

Can I compost in a metal trash can?

Metal cans are not recommended because they rust quickly and absorb too much heat, which can kill the beneficial bacteria and worms that break down the material. Heavy-duty plastic is cheaper, lighter, and lasts for years outdoors.

How do I keep pests out of a trash can composter?

A tight-fitting lid with bungee cords for extra security is usually enough. Avoid adding meat, dairy, or oily foods, which attract rats and raccoons. Elevating the can on bricks also discourages animals from digging underneath.

Why does my trash can compost smell bad?

Foul odors mean the pile has too much green material or too little air. Mix in dry browns like shredded leaves or cardboard until the ratio is about 2:1 browns to greens, and turn the can more often—every week instead of every two—until the smell fades.