What to put in a compost bin

Food waste accounts for 58% of landfill methane emissions, yet it makes up only 28% of what actually ends up in landfills. Most of that waste is good compostable material, from fruit and vegetable scraps to coffee grounds and dry leaves. Knowing what to add to a compost bin is the first step towards turning everyday kitchen and garden waste into nutrient-rich soil.

This guide covers every category of compostable items, the ideal green-to-brown ratio, tips for faster decomposition, and what to keep out to make the process simple and odour-free.

Note: Keep in mind that some of these tips may not apply everywhere. If your area uses urban or municipal composting, check your local or council regulations before adding certain materials to your bin.

What are greens and browns in a compost bin?

Compost bins rely on two types of organic material working together to fuel decomposition:

• Greens are nitrogen-rich, fresh, and moist: fruit scraps, coffee grounds, and grass clippings

• Browns are carbon-rich, dry, and fibrous: fallen leaves, cardboard, shredded paper

A balanced ratio of 2-3 parts browns to 1 part greens by volume keeps moisture in check and decomposition efficient. That means for every bucket of kitchen scraps, two to three buckets of dry material go in alongside it.

Kitchen scraps to put in a countertop compost bin

The kitchen is where most of a household's compostable food waste comes from. Fruit and vegetable scraps, coffee grounds, and pantry leftovers are all good items to add to a compost bin on a regular basis. Sorting them by category keeps the process simple and helps you get the most out of every batch.

Which fruit and vegetable scraps are compostable?

Peels, cores, rinds, and overripe produce are all compostable, along with a few less obvious scraps:

• Fresh herb stems, wilted lettuce, and bruised fruit (deliver nutrients back into the soil)

• Frozen or tinned vegetables (drain the liquid first)

• Citrus peels and onion skins (fine in moderation)

Cutting larger pieces into smaller chunks before adding them speeds up the process, so nothing sits in the bin longer than it needs to.

Coffee grounds, tea leaves, and filters

Coffee grounds are one of the most common nitrogen-rich greens in a kitchen compost bin. Paper coffee filters count as a brown and can go in with the grounds. Loose-leaf tea and paper tea bags are both compostable, but not all tea bags are plastic-free. Check for a shiny or slippery lining before you add them. If the bag feels synthetic, tear it open, compost the leaves, and throw the bag away.

Eggshells, bread, and pantry items

Crushed eggshells add calcium and other nutrients to finished compost, which is why experienced composters save every shell. Other good items to toss in:

• Stale bread and plain pasta

• Rice, crackers, and cereal

• Most nutshells (except walnut, which contains a compound that inhibits plant growth)

One tip: keep grain-based additions moderate. Too much bread or rice in one layer can clump, hold moisture, and attract pests. Mixing these nutrient-rich pantry scraps into a bed of browns prevents that problem entirely.

The kitchen generates compostable material every day, so the transition from bin to garden compost pile gets easier the more familiar you are with what belongs.

Can garden waste be composted?

Garden waste is one of the best sources of both greens and browns for a compost bin. Whether a material counts as nitrogen-rich or carbon-rich depends on how fresh it is and how much moisture it still holds. Green, freshly cut trimmings fuel decomposition, while dry, woody debris provides the structure that keeps the pile aerated.

Are grass clippings good for composting?

Freshly cut grass clippings are high in nitrogen, which makes them one of the fastest-acting greens you can add. Mix them with browns right away to prevent matting and odour. Left in a thick, wet layer, grass compacts and turns anaerobic within days. Fresh weeds are fine as long as they haven't gone to seed. Houseplant trimmings, dead flowers, and soft green prunings all belong in the bin too. Any free garden material that's still green and pliable qualifies.

Dry leaves, twigs, and wood chips

Dry leaves are the most accessible brown material for home composting. Shredded leaves break down faster than whole ones and mix more evenly with greens. Small twigs and untreated wood chips add carbon and create air pockets that keep decomposition aerobic. Avoid large branches unless you chop them first, and never add painted, stained, or pressure-treated wood. Those contain chemicals that contaminate the finished compost.

From grass clippings to fallen leaves, garden waste gives you a steady supply of both greens and browns without spending anything.

Household items safe to compost

Beyond food and garden waste, many everyday household items break down naturally in a compost bin. Paper products, natural fibres, and small organic materials are all easy additions that most people overlook. Recognising these items keeps useful material out of landfill and adds variety to the pile.

Can paper and cardboard be composted?

Paper products and natural fibres are compostable browns that add carbon and absorb excess moisture:

• Shredded newspaper

• Uncoated cardboard, egg cartons, and toilet rolls

• Paper towels and paper bags

• Cotton and wool scraps, along with natural-fibre tumble dryer lint, which also break down over time

These pair well with wet kitchen scraps. The rule is simple: if the material is dry, uncoated, and free of heavy ink or wax, it can go in the bin. Glossy magazines, wax-coated containers, and heavily printed packaging don't qualify.

Hair, nail clippings, and other organic materials

Hair, nail clippings, and other small organic items are compostable and contribute to the nutrient-rich mix that finished compost delivers to soil:

• Human and pet hair

• Nail clippings

• Wine corks and wooden toothpicks

• Pencil shavings

• Fireplace ash (thin layers only, because it's alkaline and too much shifts the pH)

Using a wide range of organic materials speeds up decomposition and produces a more balanced end product over time.

Knowing what belongs in the bin is only half the equation. Keeping the wrong materials out matters just as much.

What should not go in a compost bin?

Not everything organic belongs in a compost bin. Certain food waste, weeds carrying seeds, and treated garden material can introduce pests, strong odours, or harmful chemicals into the pile. Knowing what to throw away instead of tossing in keeps the compost clean and the process trouble-free.

Meat, dairy, and oily foods

Meat, fish, bones, cheese, and dairy products attract rodents and produce strong odours as they break down. Fats and greasy food waste slow decomposition and create anaerobic pockets in the pile. Small amounts of plain cooked grains or vegetables are fine, but anything with oil, butter, or animal-based ingredients belongs in the rubbish or kerbside food waste collection. Keep these out, and the bin stays odour-free.

Diseased plants, weeds with seeds, and treated wood

Diseased plants can spread pathogens through finished compost and infect new plantings. Weeds that have already gone to seed may survive the composting process and sprout in the garden, which defeats the purpose. Treated, painted, or stained wood contains chemicals that leach into the material and contaminate the end product. Pet waste and cat litter also don't belong, because they carry bacteria that home composting temperatures can't reliably eliminate.

With the wrong materials out of the way, the next step is getting the right balance between what goes in.

Maintaining the right green-to-brown ratio for composting

The ratio of browns to greens is the single most important factor in how well a compost bin performs:

• Ratio: 2-3 parts browns to 1 part greens by volume

• Turning frequency: every 1-2 weeks to distribute moisture and oxygen evenly

• Target moisture: a wrung-out sponge, damp but not dripping

Too much nitrogen-rich green material makes the pile wet, heavy, and foul-smelling. Too much carbon-heavy brown material dries it out and slows everything down. You need to get these two categories in balance for the bin to work properly.

A simple diagnostic helps you adjust on the fly: if the compost smells, add more browns and turn the pile to reintroduce air. If it's dry and barely breaking down, add greens and a bit of water. Once you start using this ratio as a baseline, much of the guesswork disappears, and the process means less maintenance over time.

How long does compost take to decompose?

Finished compost can take anywhere from 2 to 12 months, and the speed of decomposition depends on the bin type, materials, and how often you turn the pile.

Cutting materials into smaller pieces before adding them speeds things up across both methods.

You don't need any special tools to tell when it's done. Finished compost looks and smells like dark, crumbly soil, with no recognisable food or plant matter left. That's your first sign it's time to start a new batch.

Start composting with Compost Genie® today

All of the tips in this guide come down to one thing: getting the right material into your container. Using the Compost Genie® kitchen compost bin makes that first step simple with bins that provide a unique ventilation system to help reduce moisture and control odours.

Frequently asked questions about what to put in a compost bin

What happens if a compost bin smells bad?

A foul odour usually points to too many greens or excess moisture in the bin. Add a layer of browns like dry leaves or shredded cardboard, turn the pile to let air circulate, and check that the base of the bin drains properly.

Do compost bins attract pests?

A well-maintained bin with a balanced green-to-brown ratio and no meat, dairy, or oily food rarely attracts pests. A secure lid, regular turning, and burying fresh scraps under a layer of browns keep rodents and insects from showing up.

Can cooked food go in a compost bin?

Plain cooked vegetables, rice, and pasta are compostable in small amounts. Avoid anything with oil, butter, sauces, or meat-based ingredients, because these attract pests and create odours.

Can you put citrus peels in a compost bin?

Citrus peels are compostable and safe to add in moderate amounts. They break down slower than softer scraps, so cutting them into smaller pieces helps speed up the process.