How is Compost Made?

The raw materials used to make compost are called feedstock, and include yard trimmings and brush; clean, untreated wood waste; produce; paper; animal byproducts; oils and greases; and some liquid, such as dairy materials, beer, wine, soft drinks and other beverages. The materials are sorted and either ground or stored. The materials are then combined according to specific recipes and added to long rows, called windrows. After forming into compost windrows, temperatures of 110 to 150 degrees Fahrenheit are typically achieved within a week. After composting for two to three months, the material is placed in static stockpiles for curing, followed by screening to remove larger woodchips and foreign materials greater than 3/8-inch diameter. While in the stockpiles, the materials breakdown and beneficial microorganisms further process the materials into rich compost. The final compost is stockpiled and screened once more before it is bagged or sold in bulk for use in gardens, lawns and landscapes to provide essential nutrients to plants. The material is also tested at a laboratory and carries the United States Composting Council’s Seal of Testing Assurance (STA).