Materials You Can Add to Your Compost Bin or Pile

You can compost most plant-based kitchen scraps and yard waste. The best materials fall into two groups: greens (nitrogen-rich, usually wet) and browns (carbon-rich, usually dry). A working compost pile needs both in roughly equal amounts by weight, though the exact ratio is forgiving—most home composters succeed with a loose 1:1 mix.

The materials you choose depend on what you have access to and what your bin or pile can handle. A small kitchen container works differently from a backyard pile, and some materials break down faster than others. The lists below cover what works in most home setups.

Key Takeaways

  • Green materials include fruit and vegetable scraps, coffee grounds, grass clippings, and plant trimmings; brown materials include dry leaves, shredded paper, cardboard, and wood chips.
  • Meat, dairy, oils, and diseased plants should not go in home compost because they attract pests, create odor, or spread disease to your garden.
  • Shredding or chopping materials into smaller pieces speeds decomposition by weeks or months.
  • Layering greens and browns as you add them keeps the pile balanced and prevents odor problems.

Green Materials (Nitrogen-Rich)

Green materials are usually wet and break down quickly. They provide the nitrogen that microbes need to multiply and heat the pile. Kitchen scraps make up most of the greens in a home compost system.

Fruit and vegetable scraps are the easiest to start with: apple cores, banana peels, carrot tops, lettuce leaves, onion skins, squash ends, and tomato scraps all work. Coffee grounds and tea bags (remove the staple from tea bags first) add nitrogen and moisture. Grass clippings from an unmowed lawn are excellent, though let them dry slightly before adding so they do not mat down and block air flow. Plant trimmings from pruning, deadheading, or pulling weeds are fine as long as they are not diseased or covered in pesticide.

Manure from herbivores—horse, cow, chicken, or rabbit—can go in, though it should be aged or mixed into the pile rather than piled alone. Fresh manure can burn plants if the compost is used before it fully breaks down. Seaweed and kelp are excellent if you live near the coast and can collect them.

Brown Materials (Carbon-Rich)

Brown materials are usually dry and break down slowly. They provide the carbon structure that keeps the pile from compacting and allows air to flow through. Most home composters have access to more browns than greens, so you often end up with a surplus.

Dry leaves are the most common brown material. Shred them with a mower or by hand before adding so they do not blow away and decompose faster. Shredded paper, cardboard (remove tape and plastic windows), and newspaper all work—avoid glossy or colored inks if possible, though most modern inks are soy-based and safe. Wood chips, sawdust, and untreated wood shavings break down slowly but are useful for structure. Straw and hay (make sure it is not moldy) add bulk. Pine needles and conifer needles are acidic but can go in; they just take longer to break down.

Avoid treated wood, plywood, or anything with glue or varnish. These contain chemicals that do not belong in soil you will use for food or ornamental plants.

Materials to Avoid

Some materials should not go in home compost because they attract pests, create strong odors, spread disease, or introduce chemicals. Meat, fish, bones, and any animal products besides manure and plant-based food scraps attract rats and raccoons and create odor problems that upset neighbors. Dairy, oils, and fats do the same and also slow decomposition.

Diseased plants, weeds with seeds, and plants treated with pesticide or herbicide should stay out. A home compost pile does not usually get hot enough to kill disease spores or weed seeds—that requires sustained temperatures above 140°F, which is hard to maintain without active management. Diseased material can spread the problem to your garden when you use the finished compost.

Glossy paper, synthetic materials, plastics, metals, and glass do not belong in compost. Pet waste (dog or cat feces) can carry pathogens harmful to humans and should never go in compost used for food gardens. Sawdust from treated or painted wood contains chemicals that accumulate in soil.

How to Prepare Materials Before Adding Them

The smaller you chop or shred materials, the faster they decompose. A whole apple core takes months; chopped apple pieces take weeks. Grass clippings should be spread thin so they do not clump. Leaves break down faster if you run a mower over them or shred them by hand. Cardboard should be torn into pieces roughly 4 to 6 inches across rather than left in large sheets.

Wet materials like fresh grass or kitchen scraps should be mixed with dry materials as you add them. If you dump a bucket of vegetable scraps on top of the pile without mixing, they will mat down, block air, and start to smell. A straightforward practice is to add a layer of scraps, then a layer of shredded leaves or cardboard, then repeat.

You do not need to wash or prepare kitchen scraps beyond removing obvious packaging. Stickers on produce are fine to compost—they are designed to be food-safe and will not harm your compost or garden.

Materials That Work Better in Certain Setups

Some materials work in a large backyard pile but not in a small kitchen container or enclosed bin. Whole branches, thick wood chips, and large leaves take so long to break down that they can outlast the compost itself. In a large pile where you are adding material continuously, this is fine. In a small bin where you want finished compost in a few months, they slow the process.

Citrus peels, onion skins, and garlic scraps are safe but can repel worms if you are using a worm bin (vermicomposting). In a regular pile or bin, they are no problem. Bread, pasta, rice, and cooked food scraps can go in a regular pile but may attract pests in a small or enclosed bin. If you use a tumbler or enclosed container, stick to uncooked fruit and vegetable scraps, coffee grounds, and shredded paper.

Balancing Your Pile for Faster Decomposition

A pile that is mostly greens will smell like ammonia and attract flies. A pile that is mostly browns will sit dormant for a year or more. The sweet spot is roughly equal amounts by weight—or if that is hard to measure, roughly equal volumes of loosely packed material.

If your pile smells bad, add more browns and turn it to introduce air. If it is not heating up or breaking down after a month, add more greens and chop everything smaller. If you have a huge pile of leaves in fall and no greens to mix in, pile them separately and use them gradually through the year as you accumulate kitchen scraps. Leaves stored dry will keep for months.

Frequently Asked Questions

Can I compost bread, pasta, and cooked food?

Yes, in a large outdoor pile or bin. Cooked food breaks down like raw food and adds nitrogen. In a small kitchen container or worm bin, avoid them because they attract fruit flies and rodents. If you do add cooked food to an outdoor pile, bury it under at least 6 inches of browns so it is not visible to pests.

What about pet hair and lint from the dryer?

Pet hair and lint are mostly carbon and will break down, though slowly. They are safe to add to a regular compost pile. In a worm bin, avoid them because they can mat and block air flow. Dryer lint from synthetic fabrics takes years to decompose, so it is not worth the space.

Can I compost sawdust from my workshop?

Sawdust from untreated wood is fine. Sawdust from treated, stained, or painted wood should not go in compost meant for food gardens because the chemicals accumulate in soil. If you are unsure whether the wood was treated, leave it out.

Do I need to add water to my compost pile?

If you are adding kitchen scraps regularly, you usually have enough moisture. The pile should feel like a wrung-out sponge—damp but not dripping. If it is very dry, water it lightly when you add new material. If it is soggy and smells, add more dry browns and turn it to introduce air.

Can I compost glossy or colored paper?

Modern glossy paper and colored inks are usually soy-based and safe. Older glossy paper and magazines with heavy ink coverage are safer left out. Plain newspaper, cardboard, and uncoated paper are always fine. When in doubt, use it as mulch around plants instead of composting it.