Backyard Composting

What is Composting?

Composting is the biological decomposition of organic wastes by bacteria, fungi, worms and other organisms under controlled conditions where oxygen is available. Decomposers are not much different than people in terms of their basic needs, so be sure to provide your microbes with all of the basics:

  • FOOD Carbon and Nitrogen (Browns & Greens)
  • WATER Moist, not soggy
  • AIR Oxygen
  • VOLUME 3' long x 3' high x 3' deep or
  • 3-5 foot diameter by 3 feet high cylinder
  • PARTICLE SIZE Less than 2-3 inches

What can I compost?

Anything that was a plant. All plant materials contain nitrogen and carbon. Materials high in nitrogen are called "greens", e.g. grass clippings, manure, and kitchen scraps. Materials high in carbon are called "browns", e.g. leaves, sawdust, and wood chips. Before adding materials to the compost bin, chip or shred items so they are no more than 2-3 inches long.

Where do I compost?

There are many different types of compost systems. Choose one that you think would work best for your yard or living space.

  • Worm Bins - This is one of the most interactive and fun ways to see your food waste disappear and turn into a rich compost of worm-castings (worm poop-don't worry, it's actually pretty clean). Worm bins are easy to maintain with little oversight and are one of the quickest ways to process organic materials into compost. Worm bins can also live on a porch, on a balcony, under a sink, or out in the yard.

  • In-Vessel Stackable Bins - These are plastic boxes that have stackable layers to sit on the ground in order to keep compost piles contained and are easy to turn. For $69.00, we offer our customers at-cost BioStack compost systems. Call customer service for more information.

  • In-Vessel Tumbler - Put food materials in a tumbler that uses heat breakdown method. Turning tumbler regularly will assist the breakdown process.

  • Compost Cake - This is an open compost pile using the natural breakdown organisms that your pile will attract. Layer brown carbon materials with green nitrogen materials (see below) and watch your pile shrink! Properly watering and turning the pile every few months assist the breakdown process.

Each bin system uses the balance of nitrogen materials ("greens"- fruits and vegetables, green grass cuttings, coffee grounds and tea bags, egg shells, etc.) and carbon materials ("browns"- dry grass cuttings, straw, paper materials, dry brush, and wood shavings). Achieving the best mix is more an art gained through experience than an exact science. The ideal ratio approaches 3-parts browns to 1-part greens. Judge the amounts roughly equal by weight. Too much carbon will cause the pile to break down too slowly, while too much nitrogen can cause odor. The rule of thumb is to have your compost the moisture of a ringed-out sponge: you don't want any drops of water if you squeeze it. If your pile is dry, you can add more nitrogen materials or water the pile to give moisture.

After I build the compost pile, then what?

The compost may heat up due to biological activity and will certainly settle as the materials decompose. To speed up the process turn the compost bin periodically. Turning means taking everything out of the bin and then putting it back. Try to move the materials from the outer sides to the center.

You may add more materials at any time. Bury food wastes in the center of the pile or cover with brown materials such as leaves. You can also start a new bin for handling additional materials.

When is compost ready to use?

The compost is finished composting and ready to use when it has a uniform look (like soil), dark color, small particle size, and "earthy" odor. Most of the materials you put in will no longer be recognizable. Use finished compost as a mulch, soil amendment, or potting soil.

Need help?

  • Sonoma County Waste Management Agency's website at www.recyclenow.org

  • Marin County Hazardous & Solid Waste JPA website at www.marinrecycles.org

  • Master Gardeners is a partnership with the University of California Cooperative Extension Program. They are a dedicated, trained group of volunteers with a shared love of gardening who provide information about using compost to enrich your garden.
    Sonoma County website: groups.ucanr.org
    UC Davis Master Gardener Program: camastergardeners.ucdavis.edu/

Click here for "Compost in a Hurry" publication from the University of California on compost basics.