Composting is a fantastic way to reduce waste, enrich your garden soil, and contribute to a more sustainable lifestyle. By turning kitchen scraps into nutrient-rich compost, you can minimize landfill contributions and create a thriving ecosystem in your backyard. However, not all kitchen scraps are suitable for composting.
Some can attract pests, introduce pathogens, or disrupt the composting process, while others are compost gold. In this comprehensive guide, we’ll explore the top 12 kitchen scraps you should and shouldn’t compost, diving into the reasons why, practical tips for success, and how to maintain a healthy compost pile. Whether you’re a seasoned composter or a beginner, this article will help you make informed choices for a flourishing compost system.
Why Composting Matters
Before we dive into the specifics, let’s briefly touch on why composting is worth the effort. According to the Environmental Protection Agency (EPA), food scraps and yard waste make up about 30% of what we throw away in the United States. Composting these materials reduces methane emissions from landfills, enriches soil, and decreases the need for chemical fertilizers. A well-maintained compost pile transforms organic waste into a valuable resource, benefiting your garden and the environment. However, the key to successful composting lies in knowing what to include and what to avoid.
The Basics of Composting
Composting requires a balance of “greens” (nitrogen-rich materials like fruit and vegetable scraps) and “browns” (carbon-rich materials like dry leaves or cardboard). The ideal carbon-to-nitrogen ratio is about 30:1, which ensures proper decomposition. Aeration, moisture (like a wrung-out sponge), and occasional turning are also critical to prevent odors and speed up the process. While many kitchen scraps are excellent for composting, some can cause problems like foul smells, pest infestations, or even harm to plants when the compost is used. Let’s break down the top 12 kitchen scraps, divided into those you should compost and those you should avoid.
Kitchen Scraps You Should Compost
These scraps are compost-friendly and provide essential nutrients to create rich, healthy compost.
1. Fruit and Vegetable Peels
Fruit and vegetable peels, such as banana skins, potato peels, apple cores, and carrot tops, are composting superstars. They’re rich in nitrogen, break down quickly, and add valuable nutrients like potassium and phosphorus to your compost. Chop larger peels into smaller pieces to speed up decomposition, and bury them in the center of the pile to deter pests.
Tip: Rinse peels to remove pesticide residues if you’re not using organic produce. Avoid adding peels from fruits or vegetables treated with non-compostable waxes, like some citrus fruits.
2. Coffee Grounds
Used coffee grounds are a nitrogen-rich addition to your compost pile. They’re slightly acidic, which can benefit acid-loving plants like blueberries or azaleas when the compost is applied. Contrary to popular belief, coffee grounds don’t significantly acidify the compost pile as a whole, making them safe for most gardens.
Tip: Sprinkle coffee grounds evenly throughout the pile and mix with browns to avoid clumping. Used paper coffee filters can also be composted, as they’re biodegradable.
3. Eggshells
Crushed eggshells are a fantastic source of calcium, which strengthens plant cell walls and promotes healthy growth. They break down slowly, so crush them finely to speed up the process. Eggshells also help balance the pH of your compost pile, reducing acidity.
Tip: Rinse eggshells to remove any residual egg white or yolk, which can attract pests. Avoid adding cooked egg scraps, as they may introduce oils or seasonings that don’t compost well.
4. Stale Bread and Grains
Stale bread, rice, pasta, and other grains can be composted in small quantities. These scraps add carbon to the pile, balancing out nitrogen-rich greens. Break bread into smaller pieces and bury it deep in the pile to prevent attracting rodents or birds.
Tip: Avoid adding bread or grains with butter, oil, or sugary toppings, as these can slow decomposition and attract pests. Moldy bread is fine, as the composting process will break down the mold.
5. Tea Leaves and Bags
Loose tea leaves and used tea bags (if biodegradable) are excellent for composting. Tea leaves are nitrogen-rich and decompose quickly. Some tea bags are made of compostable materials like paper or cotton, but many contain plastic, so check before tossing them in.
Tip: Cut open tea bags to release the leaves and discard any non-compostable materials. Avoid adding tea with milk or sugar, as these can cause odors and attract pests.
6. Nut Shells
Shells from nuts like peanuts, almonds, or walnuts are compostable and add carbon to the pile. They break down slowly, so crush them to accelerate decomposition. Nut shells also improve aeration in the compost pile, preventing it from becoming too compact.
Tip: Avoid adding salted or flavored nut shells, as excess salt can harm plants. Rinse shells if they’ve been exposed to seasonings.
Kitchen Scraps You Shouldn’t Compost
These scraps can disrupt the composting process, attract unwanted critters, or harm your garden when the compost is used.
7. Meat, Fish, and Bones
Meat, fish, poultry, and bones should not be composted in a home pile. These scraps decompose slowly, produce strong odors, and attract pests like rats, raccoons, and flies. They can also harbor pathogens like E. coli or Salmonella, which may survive in a backyard compost pile that doesn’t reach high enough temperatures.
Alternative: Check if your local municipal composting program accepts meat and bones, as industrial facilities often reach higher temperatures to safely process these materials.
8. Dairy Products
Cheese, butter, yogurt, and other dairy products are problematic for composting. Like meat, they break down slowly, create foul odors, and attract pests. The fats in dairy can also coat other compost materials, slowing decomposition.
Alternative: Dispose of dairy in the trash or explore worm composting (vermicomposting) for small amounts, as worms can sometimes handle minimal dairy if managed carefully.
9. Oily or Greasy Foods
Foods cooked in oil, like fried items, or scraps with butter or salad dressing should be avoided. Oils and fats create a barrier that slows decomposition and can lead to anaerobic conditions, causing a smelly pile. They also attract pests and can rancidify, further complicating the process.
Alternative: Scrape off excess oil or grease and dispose of it in the trash before composting any associated vegetable scraps.
10. Diseased Plant Material
Vegetable scraps or garden trimmings from plants affected by diseases like blight, mildew, or fungal infections should not be composted. Many pathogens can survive the composting process, especially in a home pile that doesn’t reach high temperatures (above 140°F), and spread to healthy plants when the compost is used.
Alternative: Burn or bag diseased plant material and dispose of it through municipal waste services to prevent spreading pathogens.
11. Citrus Peels in Excess
While small amounts of citrus peels (like orange or lemon rinds) can be composted, large quantities can disrupt the pile. Citrus peels are acidic and break down slowly, potentially lowering the pH and harming beneficial microbes. They can also deter worms in vermicomposting systems.
Tip: Limit citrus peels to no more than 10% of your compost pile and chop them finely to aid decomposition. If you have excess, consider using them for homemade cleaners before discarding.
12. Pet or Human Waste
Pet feces, cat litter, and human waste should never be composted in a home system. These materials can contain harmful pathogens like Toxoplasma gondii or E. coli, which pose health risks if the compost is used on edible crops. Even high-temperature composting may not eliminate all pathogens.
Alternative: Use specialized pet waste composters designed for non-edible gardens, or dispose of waste through municipal systems.
Tips for Successful Composting
To make the most of your compost pile, follow these best practices:
- Balance Greens and Browns: Aim for a 3:1 ratio of browns (leaves, cardboard) to greens (kitchen scraps). Too many greens can make the pile slimy and smelly, while too many browns slow decomposition.
- Turn Regularly: Aerate the pile every 1-2 weeks with a pitchfork or compost tumbler to introduce oxygen and speed up breakdown.
- Monitor Moisture: The pile should feel like a wrung-out sponge. Add water if it’s too dry or browns if it’s too wet.
- Bury Kitchen Scraps: Place scraps in the center of the pile and cover with browns to deter pests and reduce odors.
- Use a Compost Bin: A enclosed bin or tumbler helps control pests and maintains consistent conditions.
- Be Patient: Depending on conditions, compost can take 2-6 months to mature. Finished compost should be dark, crumbly, and earthy-smelling.
Common Composting Mistakes to Avoid
Even with the best intentions, composters can run into issues. Here are pitfalls to watch out for:
- Adding Too Many Greens: Excess fruit and vegetable scraps without enough browns can lead to a smelly, anaerobic pile. Always balance with carbon-rich materials.
- Ignoring Pest Attraction: Failing to bury scraps or adding prohibited items like meat can invite rodents and insects. Use a secure bin and avoid problem scraps.
- Not Chopping Scraps: Large pieces, like whole banana peels or corn cobs, take longer to break down. Chop or shred scraps for faster results.
- Neglecting the Pile: A forgotten pile can become too dry, too wet, or compacted. Regular turning and monitoring keep it healthy.
Composting Alternatives
If you’re unable to compost certain scraps at home, consider these options:
- Municipal Composting: Many cities offer food scrap pickup programs that accept items like meat and dairy, which are processed in high-temperature industrial facilities.
- Vermicomposting: Worm composting is ideal for small spaces and can handle some scraps (like coffee grounds) that backyard piles struggle with, though it requires careful management.
- Bokashi: This anaerobic fermentation method can process meat, dairy, and oily foods in a sealed bucket, producing a pre-compost that can later be buried or added to a traditional pile.
Conclusion
Composting kitchen scraps is a rewarding way to reduce waste and nourish your garden, but it requires careful selection to maintain a healthy pile. Stick to compost-friendly scraps like fruit and vegetable peels, coffee grounds, eggshells, stale bread, tea leaves, and nut shells, and avoid problem items like meat, dairy, oily foods, diseased plants, excessive citrus, and pet waste. By following best practices—balancing greens and browns, turning regularly, and monitoring moisture—you can create nutrient-rich compost that benefits your plants and the planet. Start small, experiment, and watch your kitchen scraps transform into garden gold. Happy composting!