The compost tumbler is a free-standing device that uses a metal or plastic drum to hold kitchen scraps, fall leaves, grass trimmings and other organic matter. A compost tumbler can, with little effort, be rotated by hand to quickly make black, rich nutritional compost to mix in with your garden soil.

Compost tumblers do precisely what their name implies - they tumble, rotate, and mix your organic materials to allow oxygen and moisture to circulate so that tiny microorganisms can "process" the organic matter into compost. Manual handles or cranks allow for easy turning or spinning of the compost tumbler.

Working an open compost pile or compost bin with a pitchfork or rake can be a backbreaking task for some. Wet compost can be very heavy! In addition, compost tumblers provide a way for homeowners with small yards or with homeowner associations that have rules against open compost piles to get involved in composting. Tumblers can sit against the wall of a house or behind the garage, looking no more interfering than a large barbecue grill.

Compost tumblers commonly fall into four categories:

• Horizontal compost tumblers with a through shaft or axle. These tumblers are very easy to rotate with the help of handles or a crank. Most of these rotating composters are made out of galvanized steel and they are typically larger, heavier and more expensive than the other models. Some of the metal compost tumblers have dual chambers which are very convenient as you can let one chamber finish the composting process while you fill the other chamber with fresh organic materials.
• Vertical compost tumblers with a through shaft or axle. These drums are mounted vertically like a cement mixer and can be rocked back and forth until enough momentum is gained to make the spin. These tumblers are typically made out of plastic. Check to make sure that they are made with a large percentage of recycled plastic. Bear in mind that a drum full of moist compost can be very heavy, so rotating it will take more than the flip of a wrist.
• Roller-based compost drums. These drums sit on a base equipped with rollers or wheels. The rollers allow the drum to spin, mixing the organic matter inside.
• Rolling-sphere compost drums. These are large plastic balls that rest on a base equipped with rollers or wheels. Some can be rolled on the ground to mix the organic matter. (Be careful if you have a large hill or your compost ball might roll over to visit your neighbor).

Horizontal compost tumblers	Vertical compost tumblers	Roller-based compost drums	Rolling-sphere compost drums