Backyard composting is a great way to manage organic waste at home. You can build your own backyard compost bin or purchase one. The Town of Carrboro sells Earth Machine’s backyard compost bins to residents for $45 and kitchen pails for $5. Compost Bin/Kitchen Pail Order Form.
Backyard composting requires four basic ingredients:
- Greens (Nitrogen) - Vegetable scraps, fruit scraps, and grass clippings.
- Browns (Carbon) - Dry leaves, twigs, or sawdust.
Five Simple Steps to Start Backyard Composting
- Pick a Location - Place compost bin/pile in a convenient, partially sunny location with good drainage. You also want to place your bin on bare soil so bacteria and worms have direct access to your compostable materials.
- Build or Purchase a Compost Bin - Compost bins can be purchased or built using wire, wood, wood pallets, or concrete blocks.
- Start your Compost - Start compost with a layer of coarse materials such as corn stalks to build air passages. Add alternating layers of "brown" and "green" materials and mix them together (See "What to Compost"). The ideal ratio (Compost Recipe) for "brown" to "green" materials in a backyard bin is generally considered to be:
3 parts brown to 1 part green
6 inches browns to 2 inches of greens
Disproportionate amounts of “green” can lead to strong odors, and too much “brown” will dry out your pile and stop the composting process. If you don't have brown and green materials on hand at the same time, build your pile with browns, add water, and mix in the greens as they become available.
4. Water - Add water as you build your compost if the materials are dry. Compost should be damp, not wet. It should feel like a wrung-out sponge.
5. Oxygen - Mix or turn your compost. You can use a garden hoe or compost turning tool. More frequent turning will shorten the composting time.
- Keep it small. Mowing, grinding, chopping, or shedding will shorten the compost time.
- Always cover your newly added food scraps with brown materials or soil. This will help eliminate odors and control pests.
- Line the bottom of your compost bin or pile with 1/4" hardware cloth to limit access to your compost from mice or rodents.
- If your compost bin needs water, and the forecast calls for rain; remove the lid on your compost bin and let Mother Nature provide the water.
What to Compost
|Greens (Nitrogen)||Browns (Carbon)|
|Fruit/Vegetable Scraps||Leaves (Dried)|
|Grass Clippings (Fresh)||Grass Clippings (Dried)|
|Egg Shells||Pine Needles|
|Coffee Grounds||Coffee Filters|
|Tea Grounds & Leaves||Shredded Paper|
|Manure (Not Pet Waste)||Straw/Hay/Sawdust/Corn Stalks|
|Garden Waste (Fresh)||Garden Waste (Dried)|
What NOT to Compost
|Cooking Oil||Dairy Products|
|Diseased/Infested Plants||Pet Waste|
|Treated Wood||Coated/Glossy Printed Papers|
|Damp and warm only in the middle of the pile||Pile could be too small, or cold weather might have slowed composting.||If you are only composting in piles, your pile should be at least 3 feet high and 3 feet wide. Get more material and mix old ingredients into a new pile.|
|Pile smells rotten and/or attracts flies||Too wet and/or non-compostables are present.||Turn, add dry-woody materials, cover pile from heavy rains and/or remove grease, etc. and turn.|
|Stinks like rancid butter, vinegar or rotten eggs.||Not enough oxygen, or the pile is too wet, or compacted. Food wastes in open bin, holes larger than 1/4 inch or non-compostables present.||Mix up the pile so that it gets some aeration and can breathe. Add course dry materials like straw, hay or leaves to soak up excess moisture. If smell is too bad, add dry materials on top and wait until it dries out a bit before you mix the pile.|
|Odor like ammonia||Not enough carbon||Add brown materials like leaves, straw, hay, shredded newspaper, etc.|
|Pile not composting||Too dry and/or too much dry-woody material.||Moisten till slightly damp and/or turn, add fresh green materials.|
|Attracts rodents, flies, or other animals.||Inappropriate materials (like meat, oil, bones), or the food-like material is too close to the surface of the pile.||Bury kitchen scraps near the center of the pile. Don’t add inappropriate materials to compost. Switch to a rodent-proof closed bin.|
|Fire ant problems||Pile could be too dry, not hot enough, or has kitchen scraps too close to the surface.||Make sure your pile has a good mix of materials to heat up, and keep it moist enough.|
Orange County Solid Waste Management offers two outdoor composting demonstration sites where you can learn more about outdoor composting and observe in it "in action." These sites are located at:
Chapel Hill Community Center (behind the rose garden) on South Estes Drive.
Orange County Solid Waste Management Administrative Office, 1207 Eubanks Road in Chapel Hill.
Orange County Solid Waste Management teaches public composting classes in the spring and fall. The classes teach the basics or indoor composting using worms, and outdoor composting using a variety of recipes and structures.
For more information contact Orange County Solid Waste Management.