![[logo] US EPA](https://cybercemetery.unt.edu/archive/oilspill/20120924204911im_/http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}
Basic Information
Compost Pile – Photo Courtesy of Campaign Recycle Maui Inc./Compost Maui
Organic Materials | What to Compost | What Not to Compost | Which Compost to Use
Compost is organic material that can be used as a soil amendment or as a medium to grow plants. Mature compost is a stable material with a content called humus that is dark brown or black and has a soil-like, earthy smell. It is created by: combining organic wastes (e.g., yard trimmings, food wastes, manures) in proper ratios into piles, rows, or vessels; adding bulking agents (e.g., wood chips) as necessary to accelerate the breakdown of organic materials; and allowing the finished material to fully stabilize and mature through a curing process.
Natural composting, or biological decomposition, began with the first plants on earth and has been going on ever since. As vegetation falls to the ground, it slowly decays, providing minerals and nutrients needed for plants, animals, and microorganisms. Mature compost, however, includes the production of high temperatures to destroy pathogens and weed seeds that natural decomposition does not destroy.
Did You Know That Compost Can...- Reduce or eliminate the need for chemical fertilizers.
- Promote higher yields of agricultural crops.
- Facilitate reforestation, wetlands restoration, and habitat revitalization efforts by amending contaminated, compacted, and marginal soils.
- Cost-effectively remediate soils contaminated by hazardous waste.
- Remove solids, oil, grease, and heavy metals from stormwater runoff.
- Capture and destroy 99.6 percent of industrial volatile organic chemicals (VOCs) in contaminated air. See Innovative Uses of Compost: Bioremediation and Pollution Prevention
- Provide cost savings of at least 50 percent over conventional soil, water, and air pollution remediation technologies, where applicable. See Analysis of Composting as an Environmental Remediation Technology
Organic Materials
Digging in a Compost Pile with a Shovel
Yard trimmings and food residuals together constitute 27 percent of the US waste stream, as documented by EPA. An estimated 57.5 percent of yard trimmings were recovered for composting or grasscycled in 2010, a dramatic increase from the 12 percent recovery rate in 1990. Accompanying this surge in yard waste recovery is a composting industry that has grown from less than 1,000 facilities in 1988 to over 2280 in 2010 (October 2010 Biocycle State of Garbage report). Once dominated by public sector operations, the composting industry is increasingly entrepreneurial and private-sector driven, led by firms that add value to compost products through processing and marketing. Bulk retail yard waste compost sells for between $15.00 and $32.00 per cubic yard in the United States (August 2011 Compost News).
While yard trimmings recovery typically involves leaf compost and mulch, yard trimmings can also be combined with other organic waste, such as food residuals, animal manure, and biosolids to produce a variety of products with slightly different chemical and physical characteristics. In contrast to yard trimmings recovery, only 2.8 percent of food waste was composted in 2010. The cost-prohibitive nature of residential food waste separation and collection is the primary deterant to expanding food waste recovery efforts. Yet in many communities, edible food residuals are donated to the needy, while inedible food residuals are blended into compost or reprocessed into animal feed. In some areas, composting operations are working with high-volume commercial and institutional food producers to recover their food byproducts, saving these firms significant disposal costs. For more information on organic materials, please visit our Organic Materials website.
What to Compost – The IN List
- Animal manure
- Cardboard rolls
- Clean paper
- Coffee grounds and filters
- Cotton rags
- Dryer and vacuum cleaner lint
- Eggshells
- Fireplace ashes
- Fruits and vegetables
- Grass clippings
- Hair and fur
- Hay and straw
- Houseplants
- Leaves
- Nut shells
- Sawdust
- Shredded newspaper
- Tea bags
- Wood chips
- Wool rags
- Yard trimmings
What Not to Compost – The OUT List
Leave Out/Reason Why- Black walnut tree leaves or twigs
- Releases substances that might be harmful to plants
- Coal or charcoal ash
- Might contain substances harmful to plants
- Dairy products (e.g., butter, milk, sour cream, yogurt) and eggs*
- Create odor problems and attract pests such as rodents and flies
- Diseased or insect-ridden plants
- Diseases or insects might survive and be transferred back to other plants
- Fats, grease, lard, or oils*
- Create odor problems and attract pests such as rodents and flies
- Meat or fish bones and scraps*
- Create odor problems and attract pests such as rodents and flies
- Pet wastes (e.g., dog or cat feces, soiled cat litter)*
- Might contain parasites, bacteria, germs, pathogens, and viruses harmful to humans
- Yard trimmings treated with chemical pesticides
- Might kill beneficial composting organisms
* Check with your local composting or recycling coordinator as some commercially run composting facilities may be able to process the asterisked materials.
NOTE: Finished compost can be applied to lawns and gardens to help condition the soil and replenish nutrients. Compost, however, should not be used as potting soil for houseplants because of the presence of weed and grass seeds.
Which Compost to Use
Did you know there are different composts produced for different uses? To help homeowners ensure they get the right product for the right use — in 2011 the US Composting Council (USCC) launched its Consumer Compost Use Program 
for the three most common homeowner uses: flower & vegetable gardens, trees & shrubs, and lawns. Each compost use classification is represented by easily interpreted icons that reflect the best use (or uses) of that particular compost.
Here’s what to look for to find the compost that you need:
