Fruits, vegetables, dairy products, grains, bread, unbleached paper napkins, coffee filters, eggshells, meats and newspaper can be composted. If it can be eaten or grown in a field or garden, it can be composted. Items that cannot be composted include plastics, grease, glass, and metals — including plastic utensils, condiment packages, plastic wrap, plastic bags, foil, silverware, drinking straws, bottles, polystyrene or chemicals. Items such as red meat, bones and small amounts of paper are acceptable, but they take longer to decompose. Add red meat and bones to only a well-controlled compost pile to avoid attracting vermin, pests and insects to partially decomposed meat scraps.
Food Waste Is Unique as a Compost Agent
Food waste has unique properties as a raw compost agent. Because it has a high moisture content and low physical structure, it is important to mix fresh food waste with a bulking agent that will absorb some of the excess moisture as well as add structure to the mix. Bulking agents with a high C:N ratio, such as sawdust and yard waste, are good choices. Food waste is highly susceptible to odor production — mainly ammonia — and large quantities of leachate. The best prevention for odor is a well-aerated pile that remains aerobic and free of standing water. Leachate can be reduced through aeration and sufficient amounts of a high carbon bulking agent. It is normal to have some odor and leachate production. Captured leachate can be reapplied to the compost.
Benefits of Compost to the Environment and Agriculture
- Water and soil conservation.
- Protects groundwater quality.
- Minimizes odors from agricultural areas
- Avoids methane production and leachate formation in landfills by diverting organics from landfills into compost.
- Prevents erosion and turf loss on roadsides, hillsides, playing fields and golf courses.
- Drastically reduces the need for pesticides and fertilizers.
- Binds heavy metals and prevents them from migrating to water resources, being absorbed by plants, or being bioavailable to humans.
- Off-farm materials can be brought in and added to manure to make compost.
- Facilitates reforestation, wetlands restoration, and wildlife habitat revitalization efforts by amending contaminated, compacted and marginal soils.
- Composted manure weights about one-fourth as much as raw manure per ton.
- Long-term stable organic matter source.
- Buffers soil pH levels.
- Adds organic matter, humus and cation exchange capacity to regenerate poor soils.
- Suppresses certain plant diseases and parasites and kills weed seeds.
- Increases yield and size in some crops.
- Increases length and concentration of roots in some crops.
- Increases soil nutrient content and water holding capacity of sandy soils and water infiltration of clay soils.
- Reduces fertilizer requirements.
- Restores soil structure after natural soil microorganisms have been reduced by the use of chemical fertilizers; compost is a soil innoculant.
- Increases earthworm populations in soil.
- Provides slow, gradual release of nutrients, reducing loss from contaminated soils.
- Reduces water requirements and irrigation.
- Provides opportunity for extra income; high quality compost can be sold at a premium price in established markets.
- Moves manure to non-traditional markets that do not exist for raw manure.
- Brings higher prices for organically grown crops.
- Minimizes odors from agricultural areas.