What Can Be Composted?

Rich soil? Yes. Less waste? Yes-Yes. Environmental benefits? Yes-Yes-Yes! Next time you take out the trash, ask yourself if you’re bagging up things that you could compost to improve your garden soil. The answer is probably yes.

Compost organic scraps, and immediately cut back on the volume left to decay in landfills. Composting has a direct effect on the environment, as the organic materials we throw away undergo anaerobic decomposition (rotting without oxygen) and produce methane gas, which is among the most dangerous of the greenhouse gases. Adding scraps to a compost pile is advantageous for eco-enthusiasts and gardeners of all levels, because the items discarded can rot in an open area and undergo aerobic decomposition (with oxygen) and produce carbon dioxide instead of methane.

If you’re just starting your own at-home compost (or you've made a container to accessorize your kitchen), or even think you’re doing a fair job at composting food scraps instead of putting them through the disposal, remember that a nice balance of green and brown organic materials is important to generating a good pile of compost.

Think beyond “ordinary” compost additives like orange peels and eggshells, and challenge yourself to add more variety to your bin. Your resulting compost will be nutrient-rich, and you’ll have a lot more of it.

What Can You Compost?

Natural Fibers: More fibers qualify for composting than you might think: silk, leather, cotton, wool or wool felt, linen are all carbon-rich and will decompose with time. Cut the fibers into smaller pieces to help them break down faster.

Hair: Add nitrogen to the soil by composting hair pulled from hairbrushes, pet grooming tools or --ugh-- from the shower drain.

Nail Clippings: Keratin is good for the soil, and those nail clippings, though they’re tiny, will decompose well and add to the earth. Toss your pet's nail clippings in, too (chop them into smaller pieces if needed, so they break down faster).

Wood: All kinds of small pieces of wood add carbon to the soil; add layers of natural wood chips, short branches or even toothpicks, burnt matches and sawdust generated from outdoor landscaping (not treated lumber) to make the microbes in the compost more balanced. Don't use painted or treated wood.

Pine Needles: Slower to decompose, pine needles are a great brown organic material that aids air circulation in the soil. They are acidic, however, so keep the amount you add balanced with other additives. Next holiday season, add the needles swept from beneath your Christmas tree to the compost bin.

Dryer Lint: The collected fibers from your lint trap are still carbon-rich and will decompose easily in the compost, so keep a jar next to the dryer to make it easy to remember to harvest them with every load.

Unbleached Paper Products: Opt for unbleached “disposable” products such as napkins, paper plates and paper towels for your next picnic, and set up a separate bin to collect the throw-aways. These carbon-rich items will break down relatively quickly in the compost, but be wary of adding too many at one time. Also, consider folding in the items to help expedite decomposition. (Better yet, skip the paper products and ask your friends and family to use reusable items — it’s really not that inconvenient.)

Newspaper: These days, newspaper ink is non-toxic, so shred your newspapers up into narrow strips. When you put the strips in your compost, it will remain light and fluffy and the newspaper will break down more easily.

Dust: Deposit the dust you sweep or vaccum from your home into the compost. What you collect from the floors is typically all organic matter from our bodies or from soil we track into the house.

Corn Cobs: Post-picnic, toss your corn cobs in the compost to help with soil aeration. Remember to compost the husks, too, even if they've been grilled or roasted.

Rabbit or Bird Droppings: Whether from caged pets or free-roaming animals, droppings from non-carnivorous pets are a super nutrient-rich additive for your compost. Always wear gloves when handling droppings and wash your hands thoroughly afterwards.

Coffee Grounds: This daily addiction’s good for something! Add nitrogen to your soil by sprinkling grounds into the compost. Many coffee shops will offer their grounds too, so even if you’re not caffeinated, there are easy ways to get your hands on this great additive. (Throw in the coffee filter too, as long as it’s unbleached paper.)

Tea Bags: Put in tea bags without a staple or remove the staples, or opt for loose-leaf to deliver additional nutritional value to your compost.

Ashes: Natural wood, burnt, is an excellent source of potassium for the soil. As a rule of thumb, add no more than one part wood ash to 10 parts of other compost materials, so your compost won't become too alkaline. Use only ash from untreated wood; don't use ash from painted or treated wood or charcoal ashes.

Old Spices: Have they gone stale? Compost the remnants instead of simply tossing the jars. Avoid using spices with a high salt content, like taco seasoning. A bonus: spices like cayenne pepper may deter pests from plundering your pile.

Eco-friendly Packaging: Check packaging for compostability; cornstarch- and wheat-based styrofoam, which dissolves when put underwater or added to your compost, as well as BioBags, made of a plant-derived compostable resin named Mater-Bi®, are becoming more mainstream. (Special claps to Misfits Market, whose bi-weekly grocery deliveries are an absolute treat for Emily's compost bin.)

Freezer-Burned Foods: They might look icky and become mushy when they thaw, but freezer-burned foods are still organic matter, and they'll compost perfectly well. What about old, freezer-burned ice cream? Sure, but add it only in small amounts and bury it under other materials in the pile because it can attract pests.

Gelatin (jelled or powder): This protein-rich product is a great additive to the soil, as it acts as a fertilizer for plants.

Cut Flowers: When they begin to wilt and dry, cut flowers can be transferred into your compost as brown material. However, avoid putting weed flowers, such as dandelions, into the compost as it can become a spot for them to self-seed.

Cotton Swabs (if paper): If the product has a plastic stem, skip the compost, but if the swabs and stems are paper, throw the used ones into the compost to break down.

Tissues: Relatively quick to disintegrate, used tissues are safe to compost. It'll free up a lot of space in your garbage cans during allergy and cold season.

Limestone: While it naturally acts to balance topsoils in lawns and gardens, limestone is a soft rock that you can buy pre-crushed if you also need to neutralize your compost. While many gardeners once added limestone to their compost, current research indicates that it's no longer necessary or desirable. According to a 2022 article from the University of Missouri Extension, "Compost naturally becomes less acid as it matures." It goes on to say that adding ground lime can create odor, decrease the nutritional content of the compost and raise the pH of the finished compost too high for optimal plant growth.

Blood Meal: A natural additive to spike nitrogen levels in soil, blood meal doubles as a weapon against garden pests such as deer, moles, and squirrels. Use it in your compost to enhance the nutrient quality.

Peat Moss: If you’re want to fertlize plants that favor acid-rich soil, add peat moss to your compost. It’s good for holding moisture too, making it especially good if you plan to use compost as mulch or in potted plants.

Water: If you live in a dry climate or are experiencing a lack of rainfall, add water to your compost to keep it moist. Use a watering can or your garden hose. Your compost should never be soggy (and should have adequate drainage), but water is essential to help break down materials.