1. Vegetable waste of any kind. This would include waste products from making your salads, rotted vegetables, and anything that didn’t go over at dinner. We even put in an entire large pumpkin and it disappeared within 2 weeks or so into compost. Just don’t add anything hard like an avocado pit. They take too long to compost. Some say not to use cooked vegetables as well. YMMV.
2. Fruit waste. This is pretty much anything you would expect left over after eating or preparing your fruit or making fruit juice, but no hard items such as peach pits or mango pits.
3. Coffee Grounds. These add a great medley of nutrients that are very beneficial to your lawn or garden. You can apply them directly, but they are great in compost as well.
4. Fish waste including skin, fish heads, etc. Just about anything from a fish is great for the compost bin. Just no shells that will take forever to compost. Note, if your compost is close to the house, or you are using a compost heap, you may want to skip this recommendation.
5. Egg shells. Nice calcium source.
6. Some cooked meat waste is fine, but get it out of the house fast. No bones. Note to only do this inside a compost bin or it will attract pests. And no raw meat. If pests do become a problem such as raccoons and the like, stop adding meat.
7. Stale or garbage pasta, bread or rice. Note to only do this inside a compost bin or it will attract pests.
8. Leaves, just don’t overdo it. Don’t rake your yard into your compost bin. Mulch them instead.
9. Grass. Again, just don’t overdo it. Mulch it as well in large amounts.
10. Used paper towels and napkins (only if used to clean up spills of wipe your face at dinner). Do not compost towels used with chemicals and only compost towels and napkins that are made from all natural products.
11. Cheese and milk products. Note again, to only compost them in a sealed compost bin. They will attract pests in an open compost heap.
12. Horse or Cow manure.
13. All cotton underwear or socks.
3. Weeds, and this is most important. Weeds often have seeds that will survive the composting process. Then the compost will carry the weeds to the garden or lawn where it is applied.
4. Tomato clippings or cuttings from garden plants. Many plants acquire disease, and even though composting may kill most of bacteria and viruses, we still think it advisable to avoid composting them and potentially spreading disease.
5. Branches or any solid yard waste.
6. Newspaper & junk mail, we have seen some recommendations to compost your newspaper and junk mail. Don’t do it. Ink is not a healthy addition to your garden, especially not colored ink. We have seen it said that many newspapers have changed over to vegetable based dyes which are safer, but we would rather not trust that until we know for sure.
7. Used tissues. These are disease spreaders. It is unclear if the diseases could survive the composting process, but we don’t want it in our garden.
8. Human or pet feces, we have seen some recommendations saying you can use it. Don’t. However, horse manure and cow manure are fine.
9. Fat or used vegetable oil. It can attract pests, but it also can interfere with the friendly critters involved in the composting process.