What Can’t Be Composted?

These items are not environmentally sound or are not safe to compost or will reduce the quality of the fertilizer that is created by composting so these items, even if they are organic, should be discarded in the trash instead of being added to your compost pile.

animal feces

Items that Cannot be Composted

  • Dairy products (e.g., butter, egg yolks, milk, sour cream, yogurt) – Dairy products release sulfur and other odors as they decompose, which smell terrible and can create bad odor problems. The smell of rotting dairy products also sometimes attracts rodents and flies. This does not apply to eggshells, which are great for composting.
  • Diseased or insect-ridden plants – If you use plants or plant clippings that have diseases, infections, or insect infestations you will just be adding those toxins to your compost.
  • Fats, grease, lard, or oils – Just like dairy products these substances smell terrible and can attract insects and rodents as they decompose.
  • Meat bones and scraps – You can use meat bones in your compost if they have been thoroughly cleaned but if there is any meat left on the bones the smell of rotting meat will attract insects and can cause contamination of the compost.
  • Pet wastes (dog or cat feces, soiled cat litter) – If these items are handled responsibly they can be used in compost that will be used on flowers but they should not be used in compost that might be used on vegetables because they can contain parasites, viruses and other illnesses that can be hazardous for humans.
  • Yard trimmings treated with chemical pesticides – These will just put pesticides and insecticides into your compost, which will contaminate the compost and defeat the purpose of using organic compost.
  • Black walnut tree leaves or twigs – This particular species of tree has a chemical that can harm plants so don’t use it to make fertilizer.
  • Coal or charcoal ash – Also contains chemicals that are harmful to some plants.

Click here to Return from What Can’t be Composted? to Basics of Gardening