Composting at Home: How Organic Waste Becomes Garden Gold

Pick a level spot with partial shade and good drainage. Full sun dries the pile too quickly; deep shade slows decomposition. Position the site at least 10 feet from the house and away from wooden fences to prevent moisture damage. If you use a bin, assemble it now. A simple three-sided wood frame, a wire cylinder, or a purchased plastic bin all work. The minimum workable size is roughly 3 feet wide by 3 feet deep by 3 feet tall, which holds enough mass to generate the internal heat that drives decomposition.

Compost needs two categories of material:

• Browns (carbon-rich): dry leaves, cardboard torn into pieces, paper bags, straw, wood chips, paper egg cartons.
• Greens (nitrogen-rich): vegetable and fruit scraps, coffee grounds, tea bags, fresh grass clippings, plant trimmings.

A rough ratio of three parts browns to one part greens by volume keeps the pile balanced. Too many greens and the pile turns slimy and smells; too many browns and decomposition stalls.

Do not add meat, fish, bones, dairy products, oily cooked foods, diseased plants, or pet waste. These either attract pests or introduce pathogens that a backyard pile may not fully neutralize.

Start with a 3- to 4-inch layer of coarse browns at the base. This layer lets air circulate under the pile. Add a 2-inch layer of greens on top, then cover with another layer of browns. Repeat the layering until the pile reaches at least 3 feet tall, which helps it retain heat. Water each layer as you go until the material feels like a wrung-out sponge: damp throughout but not dripping. Finish the top with a layer of browns to reduce odor and discourage flies.

Check the pile every week. Push your hand or a stick into the center: it should feel warm and moist. If it is dry, water it thoroughly. If it smells like ammonia, add more browns and turn the pile. If it smells like rotten eggs, the pile is too wet and compacted. Turn it and add dry browns to restore airflow.

Turn the pile every one to two weeks using a pitchfork. Move material from the outer edges into the center, where temperatures are highest. Consistent turning can cut decomposition time by half.

Finished compost is dark brown, crumbly, and smells like damp earth. You should not be able to identify the original materials. The pile will have shrunk to roughly half its original volume. This process typically takes two to six months depending on temperature, materials used, and how often you turn the pile.

To harvest, stop adding new material and let the pile cure for two to four weeks. Then fork the finished compost into a wheelbarrow or garden cart. Any unfinished chunks can go back into a new pile.

Spread 1 to 3 inches of finished compost over garden beds and work it into the top 6 inches of soil before planting. For established beds, apply it as a top dressing and let rain and earthworms incorporate it over time. Compost improves sandy soils by increasing water retention and loosens compacted clay soils by adding organic matter that separates soil particles. For container gardens, blend compost with potting mix at a ratio of about one part compost to three parts mix. See our container gardening guide for specific soil mix guidance by plant type.