Garbage can compost bins are perfect for small spaces and areas where you cannot hide your compost. Thirty-gallon plastic garbage cans with tight-fitting lids are recommended for ease of mixing contents and providing air flow. Garbage can compost bins can be kept close to the kitchen and set up with your other recycling bins. Four garbage cans are sufficient for creating compost. In the first stage of decomposition, the materials are still bulky. As they break down, they look less like their original state and crumble when touched. In the third stage, the materials should resemble rich, black soil. Use the fourth garbage can to store finished compost.
Drill 1/4-inch holes around the circumference of the trash can. Make three rows of holes, spacing the holes 6 inches apart. Stagger the holes on each row so that they are not parallel with the holes in other rows.
Fill the bottom of the garbage can with a 2-inch layer of sawdust. The sawdust will absorb odor and excess drainage. Add sawdust to your first garbage can every time you begin a new batch.
Add your composting materials. Add manure first, as it contains microbes that will get decomposition started. Add cardboard and paper, but they should not have any glossy coatings, and printed paper should be made with soy-based ink. Shred paper and cut cardboard into smaller pieces for faster decomposition. Include kitchen scraps, but they should not include any fat, oil, moldy food or meat products.
Wet the compost materials to encourage microbial growth. Compost at all stages needs to be kept moist for microbes to thrive. Periodically check the moisture content--if it appears dry, add water to moisten the contents.
Close the lid and secure it with bungee cords. Turn the garbage cans once per week to mix the contents and encourage an even breakdown of materials. Lay the cans on their sides and roll them back and forth for five minutes. This will loosen clumps and move materials from the top to the bottom.
Remove the contents of the first garbage can and place them in the second garbage can after 30 days. Start a new batch of compost in the first garbage can, beginning with a fresh layer of sawdust and a small amount of compost from the first batch as a starter.
Transfer the contents of the second garbage can compost bin into the third can after 30 days (60 days after filling the initial can). Transfer the contents of the first can into the second garbage can. Start a new batch of compost in the first garbage can. All cans need to be mixed once per week.
Place the finished compost into the fourth garbage can after 30 days (90 days after filling the first can). Transfer the contents of compost from one can to another and start another batch. The finished product should look and smell like soil. Add small amounts of water to the fourth garbage can--do not allow the finished compost to become dry. It is ready to use in your garden at this point.