Introduction

Keeping the wrong materials out of your compost bin prevents odors, pests, and contamination. Use this quick list to know what to avoid—and why.

Never Add

  • Meat, fish, oils, and dairy: Attract pests and create strong odors.
  • Greasy/processed foods: Slow to break down; can go rancid.
  • Pet waste (dogs/cats): May contain harmful pathogens and parasites.
  • Coal or charcoal ash: Contains substances harmful to plants.
  • Diseased plants & pest-infested residues: Risk spreading problems back into the garden.
  • Invasive weeds with seeds or runners: Can survive and spread when compost is used.
  • Glossy/colored paper and synthetic fibers: Inks/coatings can be problematic; plastics won’t break down.
  • Large branches or thick wood: Extremely slow to decompose (chip first or keep out).

Use with Caution

  • Citrus peels & onion skins: Fine in small amounts; chop and mix well.
  • Compostable packaging: Only if certified and torn into small pieces.
  • Bread & grains: Attracts pests—bury deeply and cover with browns.
  • Weeds without seeds: Hot piles are safer; avoid if your pile is cool.

Safe Alternatives

  • Bokashi: Can handle small amounts of meat/dairy by fermenting first.
  • Municipal green waste programs: Good for materials your home system can’t process.

Conclusion

Stick to fruit and veggie scraps, coffee grounds, tea, garden trimmings, and plenty of browns. When in doubt, leave it out—or use bokashi as a pre-treatment.