Composting turns food scraps and yard waste into nutrient-rich soil, but not everything belongs in the compost bin. Vegetable peels and grass clippings are great for compost, while meat and pet feces should be avoided.
Knowing what you can and cannot compost ensures that your pile breaks down efficiently and produces high-quality soil. Adding the wrong materials can slow the process, introduce harmful bacteria, or even damage plants when compost is used. By composting correctly, you reduce waste and contribute to a more sustainable environment.
In this guide, we’ll break down exactly what can and cannot be composted, helping you make informed choices for a healthier compost pile. We’ll share expert tips on balancing greens and browns, avoiding common mistakes, and ensuring your compost stays odor-free and nutrient-rich.
What is composting?
Composting is the process of breaking down organic materials like food scraps and yard waste into a nutrient-rich soil additive called compost. Microorganisms, worms, and fungi help decompose these materials over the course of weeks to months, turning them into a dark, crumbly soil amendment that improves the health of your lawn, garden, and plants.
Composting reduces the amount of waste that ends up in landfills. “In the U.S., food is the single most common material sent to landfills, comprising 24.1 percent of municipal solid waste. When yard trimmings, wood, and paper/paperboard are added to food, these organic materials comprise 51.4 percent of municipal solid waste in landfills,” according to officials at the Environmental Protection Agency.
In landfills, these materials decompose without oxygen and emit methane, a potent greenhouse gas. By composting, we can reduce landfill waste, lower harmful emissions, and produce a valuable resource that enhances soil health and promotes plant growth.
Composting is a long process and can be overwhelming for some homeowners. Contact a local Lawn Love pro to discuss your options, including lawn fertilization.
Read more detailed information in our guides:
- What Is Compost?
- How to Use Compost
- The 12 Best Compost Bins
- 13 Easy DIY Compost Bin Builds for Beginners
- What is Bokashi Composting?
- What is Vermicomposting?
What you can compost
To successfully compost, it’s essential to maintain a balance between two key ingredients: greens and browns.
Greens, including fruit and vegetable scraps as well as fresh grass clippings, provide nitrogen, which fuels the microorganisms that accelerate decomposition. Browns, such as dried leaves and cardboard, contribute carbon, helping to prevent excess moisture and unpleasant odors.
“Greens provide moisture and nutrients, while browns help with aeration and moisture retention. Two-to-three parts brown to one-part green is a recommended ratio,” explains Eliza Hensel, an extension agent at Michigan State University.
To speed up decomposition, chop materials into smaller pieces before adding them to your compost pile. Keep the pile moist but not overly wet. Regularly turning the compost every one to two weeks with a pitchfork or aerator introduces oxygen, which supports beneficial microbes and prevents foul odors.
Read more: The Basics of Backyard Composting
Kitchen waste
- Fruit and vegetable peels and scraps: Break down quickly and add valuable nutrients.
- Coffee grounds and paper coffee filters: Rich in nitrogen, unbleached filters decompose easily.
- Tea bags: Many are made from synthetic fibers; only use those that are free of plastic.
- Eggshells: Provide calcium but decompose slowly unless crushed.
- Corncobs: Take longer to break down but decompose faster when cut into smaller pieces.
- Stale bread, rice, and pasta: Break down well in small amounts but can attract pests if oily or sauced.
Yard waste
- Grass clippings: Provide nitrogen but should be added in thin layers to prevent matting.
- Leaves: Rich in carbon, shredded leaves decompose faster.
- Small twigs and branches: Break down slowly but compost more efficiently when chopped into small pieces.
- Dead plants and flowers: Safe to compost unless they are diseased, which can spread pathogens.
- Thatch: Helps aerate compost but should be used in moderation to prevent clumping.
- Wood chips and sawdust: Decompose slowly and should come from untreated wood to avoid chemicals.
- Manure: Adds valuable nutrients but should come from plant-eating animals like cows, horses, or rabbits.
Paper products
- Paper towels and napkins: Only use if free from grease, oils, or chemical residues.
- Cardboard: Breaks down faster when shredded, and must be free from coating, ink, or plastic.
- Newspaper: Only use pages with black-and-white ink, as colored inks may contain toxins.
- Shredded paper: Decomposes well but should be non-glossy and free from colored dyes.
- Brown paper bags: Provide carbon and break down easily when torn into smaller pieces.
What you cannot compost
Not all organic materials are suitable for composting. Keeping the wrong materials out of your compost pile ensures that it remains balanced, decomposes efficiently, and provides safe, nutrient-rich soil for your plants.
“Some items that should not be used are grease, fat, meat scraps, and bones,” recommends David Trinklein, a horticulture extension specialist at the University of Missouri. “These materials may attract dogs, rats, or other animals. They also may develop an unpleasant odor during decomposition. Fats are slow to break down and greatly increase the time required before the compost can be used.”
Food items to avoid
- Meat, fish, and bones: Attract pests and decompose slowly, causing odors.
- Dairy products: Create foul smells and encourage unwanted animals.
- Oily or greasy foods: Prevent airflow in compost and slow decomposition.
- Cooked food scraps: Often contain oils, fats, or dairy, which can cause odor and attract pests.
Non-organic materials
- Plastic, metal, or glass: Don’t break down and contaminate compost.
- Coated or glossy paper: Contains plastic or chemicals that do not decompose.
- Synthetic fabrics: Made from non-biodegradable fibers like polyester and nylon.
Yard waste to avoid
- Diseased or pest-infested plants: Can spread disease or pests to healthy plants when compost is used.
- Large branches or logs: Too difficult to break down.
- Weeds with seeds: Will infest your pile and sprout in your garden.
- Treated or painted wood: Contains chemicals that can harm soil and plants.
Other problem materials
- Pet feces or litter: Can carry harmful bacteria and parasites.
- Harsh cleaning products or pesticides: Contain chemicals that disrupt compost microbes.
- Chemical-treated lawn clippings: May introduce harmful residues to your compost.
- Coal or charcoal ash: Contains toxins that can damage plants.
FAQs about composting
No, pet feces should not be added to regular compost because it can contain harmful bacteria and parasites that pose health risks.
Cooked foods shouldn’t be composted because they often contain oils, fats, dairy, or meat, which can create strong odors and attract pests like rodents and flies.
If you compost something you shouldn’t, it may slow down decomposition, create unpleasant odors, attract pests, or introduce harmful bacteria. If you notice issues like a bad smell or unwanted animals around your compost, try removing the problematic material and balancing the pile with browns, like dry leaves or cardboard, to absorb excess moisture and odors.
Find a lawn care professional near you
At first, learning what to compost and what to avoid took some trial and error, but once I understood the basics that I outlined in this guide, my lawn and garden thrived like never before.
If maintaining your lawn feels overwhelming, a local lawn care professional can assist with essential tasks such as mowing, leaf removal, and aeration before compost application. Their expertise ensures a well-maintained yard year-round.
Sources:
- “Composting.” Environmental Protection Agency.
- “Tips for composting in the summertime.” By Eliza Hensel, extension agent. Michigan State University.
- “Making and Using Compost.” By David Trinklein, Horticulture extension specialist. Missouri State University.
Main Photo Credit: Pexels
