Outdoor Composting

If you are interested in developing an onsite composting program, first check with your local community or county waste and recycling coordinator to identify any restrictions on outdoor composting. A properly constructed compost pile is needed to minimize nuisances (such as odors) and achieve a quality finished compost.

You will need space, a bin, oxygen, water, leaves, grass and organics. Bins are available commercially, but can also be made with wood, fence posts, chicken wire, etc. Almost all natural, organic materials will compost, but not everything belongs in an onsite compost pile (see Table 2). Generally speaking, meat, bones and fish should not be composted because they can attract rodents, raccoons and other pests and can cause odors in your compost pile. Dog and cat manure should also not be composted, as it contains harmful pathogens that are not always killed by the heat of the compost pile.

Making an outdoor composting bin yourself is inexpensive and relatively easy, or there are many types of bins available commercially. Commercial bins are typically square or cone-shaped. Some are open and some have a lid. Each type of bin has advantages and disadvantages, so choosing the type that is best for your space and complies with local requirements is important.

Advantages and disadvantages of an open bin:

• Convenient for adding new materials
• Open bins collect rain water and can become too wet (they can be covered during rain
• events to control moisture levels)
• Can attract flies, bees, rodents and urban wildlife
• Materials can be difficult to mix
• May be an eyesore to your neighbors

Advantages and disadvantages of enclosed containers:

• Containers rarely attract pests
• Upright containers may be more aesthetically pleasing
• Rotating drums are easier to mix and unload
• Upright containers may be difficult to mix or turn
• Enclosed containers require moisture to be added periodically

You can construct your own outdoor composting bin from scrap material or from materials purchased from a local hardware or home improvement store:

• Use an old metal or plastic garbage can. Puncture numerous holes throughout the can to provide air flow and oxygenation and allow excess moisture to drain. The can may be placed in a discreet corner of your yard. Raising it off the ground will provide added ventilation.
• Old snow fencing can be used to enclose the sides of a bin.
• Spare wood can be used to build a crate-like structure.
• Wire mesh or chicken wire can be used to enclose the bin.

When selecting a location for your bin, choose a site that is level, well-drained and easily accessible. By placing the bin over bare ground rather than concrete, worms and other beneficial organisms can more easily make their way into the pile. It is a good idea to remove any grass or plants under the bin and turn the soil to a depth of 6 to 8 inches.

When gathering materials to compost, keep in mind that a good mix of carbon and nitrogen nutrients are needed. An ideal mix is approximately 2 parts of carbon (brown matter) to one part nitrogen (green matter). A proper moisture content is necessary as well; the material should feel damp, but should not drop much water when squeezed by hand.

At the bottom of the bin, create a 4 inch (10 cm) layer of brush, twigs, hay or straw. Add a 4 inch (10 cm) layer of brown material, then a thin layer of good garden soil. That is one layer. Add a 4 inch (10 cm) layer of green materials topped with a thin layer of good garden soil. Moisten each layer by misting it lightly with a garden hose. Keep adding material in alternating layers of browns and greens until the bin is full. Microorganisms need both carbon (energy) and nitrogen (photo synthesis) to thrive. For every one unit of nitrogen used by bacteria, they will consume 30 units of carbon. Using different combinations of green and brown materials will help accelerate the composting process. Too much brown material will result in a pile that takes longer to break down, and too much green material will result in slime that smells and does not heat up effectively.

Once the bin is full, turn the pile every 10 to 14 days until the composting process is completed. It can take anywhere from two months to one year to produce finished compost. The time frame varies depending on the combination of materials used, temperature and moisture content of the pile.

Finished compost is dark, crumbly, broken down, and has a pleasant earthy smell. It is common to have some recognizable pieces of leaves or twigs remaining. Finished compost is a good soil amendment and fertilizer for:

• House plants
• Flower and vegetable gardens
• New planting areas
• Existing trees and bushes
• Lawn top-dressing

This information has been taken from the the Illinois Recycling Association's Workplace Recycling Toolkit.

Educator Workshops and Resources
Angelic Organics Learning Center 
(locations in Caledonia and Chicago)
(815) 389-8455 or (773) 288-5462
learngrowconnect.org

Growing Power Urban Farm
Milwaukee, WI
(414) 527-1546
or Chicago Projects Office
(773) 486-6005;
growingpower.org

CompostMania
compostmania.com

University of Illinois Extension
web.extension.illinois.edu

Chicago Botanic Garden
Glencoe
(847) 818-2901 or (847) 298-3502
chicago-botanic.org

Resource Materials
Cornell University - Educational Materials
cwmi.css.cornell.edu

University of Illinois Extension
web.extension.uiuc.edu
urbanext.uiuc.edu

Composting Bins and Rain Barrels
composters.com

Green Cone
(800) 807-6527
solarcone.net

US EPA
Greenscaping Your Lawn and Garden (#530-K-03-002)
epa.gov

US EPA
Food Waste Management Tools and Resources
epa.gov

US Composting Council
Best Management Practices (BMPs) For Incorporating Food Residuals Into Existing Yard Waste Composting Operation
epa.gov

Master Gardening
mastergardening.com