Quick answer: You can compost fruit and vegetable scraps, coffee grounds, eggshells, dry leaves, paper, and garden trimmings. Avoid meat, fish, dairy, oily or cooked food, diseased plants, and pet waste, as these cause odours, attract pests, or spread disease.
Why the Right Materials Matter
Good compost depends on what you put in. The right mix of materials breaks down into rich, sweet-smelling compost, while the wrong items create smells, attract rodents and flies, or introduce disease. Knowing what belongs in your bin is the key to trouble-free composting.
What You CAN Add to Compost
Greens (Nitrogen-Rich)
These include fruit and vegetable peels, vegetable scraps, fresh grass clippings, green garden trimmings, coffee grounds, and tea leaves. They provide nitrogen and moisture, feeding the microbes that drive decomposition.
Browns (Carbon-Rich)
These include dry leaves, shredded paper and cardboard, straw, sawdust from untreated wood, and dried plant stalks. Browns add carbon and structure, keeping the pile airy and balanced.
Other Safe Additions
Crushed eggshells, nutshells, used paper napkins, and small amounts of wood ash can all be added in moderation. Chopping everything small helps it break down faster.
What You CANNOT Add to Compost
Meat, Fish and Dairy
These rot, smell strongly, and attract rats, flies, and other pests. Keep them out of home compost bins entirely.
Oily and Cooked Foods
Greasy, oily, or heavily cooked leftovers slow decomposition and draw pests, so avoid them.
Diseased or Pest-Ridden Plants
Composting sick plants can spread disease back into your garden, since home compost rarely gets hot enough to kill all pathogens.
Pet Waste and Weeds With Seeds
Dog and cat waste can carry harmful organisms, and weeds that have set seed may survive to sprout later. Leave both out.
Items to Add Only in Moderation
Citrus peels, onion, and garlic are fine in small amounts but can deter worms in vermicompost if overused. Glossy or coated paper, treated wood, and synthetic materials should be avoided altogether.
Boosting Your Finished Compost
Once your compost is ready, you can combine it with bio-fertilizers to add beneficial microbes, or use it alongside fertilizers for hungry, fast-growing crops. Compost improves the soil while these inputs top up specific nutrients.
Why Some Items Cause Problems
Understanding the reasons behind these rules makes composting easier. Meat, fish, and dairy rot quickly and release strong odours that attract rodents and flies, while oily foods coat materials and block the air microbes need. Diseased plants are risky because home compost seldom reaches the high temperatures required to kill plant pathogens, so the disease can survive and return to your garden. Pet waste from dogs and cats can carry parasites and harmful bacteria, which is why it is unsafe for compost used on edible plants.
Tips for a Healthy Compost Bin
To keep your bin balanced, chop materials small so they break down faster, and always cover fresh kitchen scraps with a layer of browns to deter flies and lock in odours. Maintain the rough two-to-three parts browns to one part greens ratio, keep the pile as moist as a wrung-out sponge, and turn it regularly for air. Following these simple habits gives you rich, crumbly compost without smells, pests, or problems.
Frequently Asked Questions
Can I compost citrus and onion?
Yes, in small amounts. In worm bins, use them sparingly, as worms dislike too much acidity.
Can I put cooked food in compost?
Avoid oily or cooked leftovers, as they smell and attract pests. Stick to raw scraps.
Are eggshells good for compost?
Yes. Crushed eggshells add calcium and break down over time.
Can I compost paper and cardboard?
Yes, if it is plain and uncoated. Shred it first and avoid glossy printed material.
