Compost made from yard wastes, such as leaves and grass clippings, rarely contains any harmful materials. Problems can occur, however, when compost is made from partially sorted municipal refuse, certain industrial wastes, or sewage sludge. In those cases, unacceptable levels of toxic metals, chemicals, or harmful bacteria may be present.
Composting 101: What Is Compost?
Make a habit of adding compost to the soil each planting season because it is rich in nutrients, and it promotes soil microbes that aid plant growth. In a nutshell, compost is decomposed organic matter. Composting is a natural process of recycling organic material such as leaves and vegetable scraps into a rich soil amendment that gardeners fondly nickname Black Gold.