Composters come in various shapes and sizes. Nature- Mill’s Automatic Indoor Composter (above left) contains a microchip that controls such factors as temperature, airflow and mixing of materials. The Compost Cottage (center) has a 106-gallon capacity and includes a hinged door at the base for unloading mature compost. The Eco-Cycle Base Tumbler (above right) features a detachable base that can collect up to five gallons of compost tea.

Compost, often referred to as “black gold,” adds a plethora of benefits to soil. Critical to the process of creating compost is a roomy and sturdy composter to hold such raw materials as vegetable peelings and dry leaves as they decompose to a rich organic state. Compost fertilizes and nourishes the earth, enables soil to retain water and nutrients, and aerates the ground to facilitate root growth, says Tyler Storey, a garden and landscape coach based in Phoenix.

“Key points to consider when choosing a composter are size, moisture retention, ventilation (or air circulation) and drainage,” he explains. A structure as simple as a compost pile framed by four low walls, or even a converted garbage can, will serve as an effective composter. To ensure adequate aeration, a compost pile must be turned regularly, usually with a spading fork, notes Storey.  

“New composters make the process easier and quicker,” says Charlie Nardozzi of the National Gardening Association. Models that have side and bottom access facilitate the mixing of materials in the middle and bottom sections with those in the top of the pile. Plastic composters, which should be UV-resistant, may be fully enclosed with ventilation holes in the sides and lid. Separate chambers—one for raw materials, one for compost in process, and one to store the end product—are helpful features, notes Nardozzi. Also consider a compost tumbler, which usually is made from a barrel on props that can be turned upside down or spun periodically. “A tumbling composter might be an option, but be certain it’s one you can turn or roll easily,” Storey suggests. Be sure to select a tumbler that has an effective baffle system—one with interior paddles to mix the compost.

The Garden Estate Bin features removable front rails for easy access

Our experts provide the following tips for evaluating a composter:

THINGS TO LOOK FOR
• A suitable cover: In the Southwest, particularly during the hot summer, a composter that has a lid facilitates moisture retention. 
• Portability: Choose a composter that can be relocated easily to other areas of the yard. 
• Stability: If you opt for a tumbler, be certain that the frame is sturdy and that the composter’s center of gravity is low, so it cannot be easily tipped.
• Compost tea: Compost tea is the liquid generated most often by straining mature compost with water through a mesh material. The tea is excellent for watering the garden, as the nutrients are readily available to plants. Look for composters that also make the tea, or models designed specifically to produce the liquid.

THINGS TO AVOID
• Awkward access or height: If the opening at the top of the composter is too small, you will not be able to turn the pile easily. A composter that is too tall for your height will impede turning. 
• Small size: A compost pile must be large enough to create the right environment for microorganisms to begin breaking down material yet compact enough to allow you to turn and aerate the pile; a height, width and depth of 3 feet each would be an ideal size. Any shape is fine.
• Complexity: Keep it simple. If a composter’s features are too complicated, people tend not to use it, Storey observes.

WHERE TO FIND THEM
• Municipalities: Many cities offer composters at affordable prices, and some towns, like Chandler, Tempe and Gilbert—all in Arizona—will deliver them. Check with your local government’s sanitation department to find out if they provide composters.
• The Internet: The National Gardening Association’s online garden shop at garden.org offers a variety of composters, from simple wire-mesh bins to rolling tumblers. The Gardener’s Supply Co. at gardeners.com features a number of composters, such as the triple-chambered Earthmaker™. At cleanairgardening.com, many models are available, including a circular tumbler that also collects compost tea. At soilsoup.com, the focus is on compost tea makers. Also try composters.com, which features a diverse selection.
• Garden stores: Southwest Gardener in Phoenix stocks a square wire composter and a compost turner. “It’s like a big giant screw that you screw in and out,” says co-owner Amy Carlile.