Composting is an eco-friendly activity that can also save homeowners money on fertilizer and pesticides. Organic material that can be added to soil to help plants grow, compost reduces the amount of waste that would otherwise end up in landfills, reducing the amount of methane gas that such landfills produce. But the U.S. Environmental Protection Agency notes that not everything can be added to compost piles. The following are some items homeowners should not add to their compost piles or bins, courtesy of the EPA.
- Black walnut tree leaves or twigs: Leaves or twigs from black walnut release substances that might prove harmful to plants.
- Coal or charcoal ash: Coal or ash from charcoal, such as the ash that builds up in the bottom of charcoal grills, may contain substances that are harmful to plants.
- Dairy products: When added to compost piles, dairy products, including butter, milk, sour cream, yogurt and eggs, can be malodorous and may attract pests, including rodents and flies.
- Diseased or insect-ridden plants: The diseases and insects that plague plants may survive being transferred to compost piles. When the compost is ultimately distributed, these diseases and insects might then plague other plants.
- Fats, grease, lard, or oils: Fats, grease, lard or oils also may attract rodents and flies, and that might be due to the unpleasant odors such substances can produce when added to compost piles.
- Meat or fish bones and scraps: Like fats, grease, lard or oils, scraps from meat and fish and fish bones can smell unpleasant, potentially attracting rodents and flies.
- Pet waste: Pet waste, including soiled cat litter, may contain parasites, bacteria, germs, pathogens, and viruses that can be harmful.
- Grass trimmings treated with chemical pesticides: Trimmings from grass that was treated with chemical pesticides can negate the effects of composting by killing beneficial organisms produced within compost piles or bins.