What Can Go Into a Compost Bin? | Greens, Browns & What To Skip

A healthy home compost bin needs roughly two to three times more carbon-rich browns than nitrogen-rich greens, plus a careful list of materials you should keep out.

The short answer to what can go into a compost bin is most plant-based kitchen scraps and yard waste—and the secret to keeping the pile working well is getting the ratio right. Fruit and vegetable trimmings, coffee grounds, eggshells, grass clippings, dry leaves, shredded cardboard, and small twigs all belong there. But meat, dairy, oily foods, and dog or cat waste create odors and attract pests, so those stay out of standard backyard bins.

What You Can Compost: The Full List By Category

Compostable materials fall into two categories: greens (moist, nitrogen-rich) and browns (dry, carbon-rich). A balanced mix keeps the pile breaking down fast without smelling. Here is the breakdown of what goes in a typical home bin.

Greens (Nitrogen) — these supply the protein microbes need to multiply:

• Fruit and vegetable scraps (peels, cores, rinds)
• Fresh grass clippings (add in thin layers to avoid matting)
• Coffee grounds and paper filters
• Tea leaves (check that the bag is plastic-free)
• Plant trimmings and fresh weeds (avoid weeds that have gone to seed)
• Eggshells (rinse and crush for faster breakdown)

Browns (Carbon) — these provide energy and create the air pockets that prevent odors:

• Dry leaves and straw or hay
• Shredded cardboard and newspaper (uncoated, non-glossy)
• Paper towels, napkins, and uncoated paper plates
• Small twigs and wood chips
• Sawdust from untreated, raw wood only
• Shredded office paper and brown paper bags

Other accepted items (in moderation): bread, pasta, plain cooked rice, nutshells, hair, natural-fiber clothing or fabric scraps, and small amounts of wood ash. If you are ready to start indoors, our tested product roundup of the best small compost bins for kitchen counters makes collecting scraps cleaner and easier.

What Should Stay Out of a Home Compost Bin

The EPA and university extension services agree on a short no-go list for standard backyard bins. These materials either attract pests, create bad smells, or survive the process without breaking down.

• Meat, fish, bones, and shellfish shells
• Dairy products (milk, cheese, yogurt)
• Cooked food scraps and oily or greasy foods
• Dog and cat waste (contains pathogens harmful to humans)
• Diseased plants and invasive perennial weeds (bindweed, quackgrass)
• Plastics, metal, and glass of any kind
• Coal or charcoal ash (contains sulfur and heavy metals)
• Compostable plastics (most require industrial facilities, not backyard piles)

Sealed hot-compost systems can handle some of the no-go items like cooked food or small amounts of dairy because they sustain higher temperatures. Check your unit’s manual before adding anything not on your standard list.

How To Keep Your Compost Healthy: Ratio and Preparation

Getting the mix right is the single most important composting habit. The US EPA recommends starting with a 4- to 6-inch layer of bulky browns like twigs and wood chips at the bottom for airflow, then layering about 2 to 3 parts browns to 1 part greens by volume. That ratio is the sweet spot: too many greens and the pile gets slimy and smelly; too many browns and it takes forever to break down.

A few preparation tricks make everything work faster. Chop or shred large pieces of cardboard, woody prunings, and whole leaves—cutting surface area speeds decomposition and creates air pockets. Sprinkle grass clippings in thin layers so they don’t form wet, airtight mats. Limit wood ash to a thin sprinkle per layer, because too much raises the pH and slows microbial activity. If you use sawdust or wood chips, confirm they come from untreated lumber only; pressure-treated wood contains chemicals that don’t belong in garden soil.

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