Which Items Are "Greens" and Which Are "Browns"?

Composting Questions

Food waste recycling compost
Peter Dazeley

Composting is a great way to turn your kitchen refuse into fertilizer for your garden. The average household produces more than 200 pounds of kitchen waste every year. Reduce the organic trash you send to the landfill if you can.

If you are new to composting, then there is a way to go about it. You have to feed the pile appropriately to make sure that microorganisms that are breaking down the mix are not overwhelmed and can multiply.

Composting includes a balanced "browns mix" and "greens mix." Greens are materials that are rich in nitrogen or protein. They are also the items that tend to heat a compost pile up because they help the microorganisms in the pile grow and multiply quickly.

Browns are carbon or carbohydrate-rich materials. The main job of browns in a compost pile is to be food sources for all of the lovely soil-dwelling organisms that will work with the microbes to break down the contents of your compost pile. Also, brown materials help to add bulk and help allow air to filter through the pile.

All forms of kitchen waste can be composted but you might want to skip composting meat, dairy, and fats. These items will eventually break down but take much longer. And, these items are guaranteed to smell bad and attract flies, rodents, and other unwanted pests. If you truly want to compost your meat scraps, consider a Bokashi compost bin system.

Browns for the Compost Pile

Brown materials for composting includes dry or woody plant material. In most cases, these materials are brown, or naturally turn brown:

  • Fall leaves
  • Pine needles
  • Twigs, chipped tree branches/bark
  • Straw or hay
  • Sawdust
  • Corn stalks
  • Paper (newspaper, writing/printing paper, paper plates and napkins, coffee filters)
  • Dryer lint
  • Cotton fabric
  • Corrugated cardboard (without any waxy/slick paper coatings

Greens for the Compost Pile

Green materials for composting consists mostly of wet or recently growing materials. Green materials are usually green or come from plants that were green at some point. But, this is not always the case.

  • Grass clippings
  • Coffee grounds/tea bags
  • Vegetable and fruit scraps
  • Trimmings from perennial and annual plants
  • Annual weeds that haven't set seed
  • Eggshells
  • Animal manures (cow, horse, sheep, chicken, rabbit, etc. No dog or cat manure.)
  • Seaweed

The Ratio

You will often see recommendations for an ideal ratio of browns to greens. Generally, a ratio of three- or four-parts browns to one-part greens is great, but you do not need to be exact about it.

If you do not get a good mix of brown and green materials, your compost pile may not heat up, may take forever to breakdown, and may start stinking up the place. These issues can usually be remedied easily by tweaking the ratio.

If you find that your compost pile is not heating up, then you may need to add more green material to the compost. If you find that your compost pile is starting to smell, you may need to add more browns.

In the end, decomposition happens. It is a natural process. Pile your compostables, turn them (or not) and, in time, you will have compost. It really is that simple.