California Department of Resources Recycling and Recovery (CalRecycle)

Backyard Composting

Households

Food Scraps

To reduce wasting food at home, we suggest better meal planning. Use a shopping list, and prepare only enough food to be eaten during a meal. Meal planning benefits you by saving money and benefits the environment by saving resources. For the scraps that are produced at home, set up a compost bin to make compost by mixing food scraps and greenwaste in your backyard.

In the kitchen, first things first. Here are a few suggestions:

  • Meal portion planning is the best way to save money and resources. Plan weekly meals and buy only what you can cook before it spoils.
  • Rediscover the art of soup and making soup stock with wilted vegetables. Boiling animal bones makes a tasty stock for soups and stews, but put the bones in the garbage after boiling.
  • Store leftovers in single portion containers so you can use them for lunch the next day.
  • Store some things in the freezer. Properly frozen bread, for example, can be used as needed throughout the week. Bake it back to freshness as you need it.
  • Collect food prep scraps neatly, and then take them out to the backyard bin before they get smelly. Collect vegetable scraps, egg shells, paper towels, left-over rice, pasta, or bread. Don't include oils, dairy, or meats.

There are plenty of functional under-sink containers; check out the online resources list below or visit a local hardware store.

Backyard Composting

The best way to compost food waste is to mix it with dry leaves, sticks and twigs, wood chips, sawdust, dried/dead plants, shredded newspaper, or paper from a home shredder, and mixed yard waste. Always cover fresh material with a layer of wood chips and a dusting of dirt, or with unscreened, mature compost. A compost pile in your backyard will have lots of microbes taking up residence. Keep in mind that the microbes need oxygen, water, and food; the same things we need to survive. If the pile gets too wet or dense with food scraps, it will smell bad and composting will slow down or stop altogether.

Here are some helpful links:

 

Recipe for Backyard Composting

Ingredients

While a multitude of organisms, fungus and bacteria are involved in the overall process, there are four basic ingredients for composting: nitrogen, carbon, water, and air. The easiest compost recipe calls for blending roughly equal parts of green or wet material (which is high in nitrogen) and brown or dry material (which is high in carbon). Simply layer or mix these materials in a pile or enclosure; chop or shred large pieces to 12" or shorter. Water and fluff the compost to add air. Then leave it to the microorganisms, which will break down the material over time.

Nitrogen

Green materials such as grass clipping and landscape trimmings are ideal sources of nitrogen for composting. Vegetable and fruit trimmings and peels can also provide nitrogen for composting. Coffee grounds and tea bags may look brown, but are actually potent nitrogen sources. To reduce the potential for pests or odors, avoid meat or dairy scraps and always bury food scraps deep within the compost pile. Avoid pet feces due to concerns about pathogens. However, manure from chickens, turkeys, cows or horses is rich in nitrogen, and can help your compost pile get to proper temperatures, and make very good compost.

Carbon

Brown (dry) yard and garden material such as dry leaves, twigs, hay, or shredded paper can provide the carbon balance for a compost pile. Chop or shred large pieces to 12 inches or shorter (thick, woody branches should be chipped, ground up, or left out). Untreated wood chips and sawdust are a powerful carbon source which may be useful if the pile contains excess nitrogen.

Water

One of the most common mistakes in composting is letting the pile get too dry. Your compost pile should be moist as a wrung-out sponge. A moisture content of 40 to 60 percent is preferable. To test for adequate moisture, reach into your compost pile and grab a handful of material and squeeze it; if a few drops of water come out, it's probably got enough moisture, if it doesn't, add water. When you water, it is best to put a hose into the pile so that you aren't just wetting the top. You can also water as you are turning the pile. During dry weather, you may have to add water regularly. During wet weather, you may need to cover your pile. A properly constructed compost pile will drain excess water and not become soggy.

Air

The bacteria and fungus that are in your compost pile need oxygen to live. If your pile is too dense or becomes too wet, the air supply to the inside is cut off and the beneficial organisms will die. Decomposition will slow and an offensive odor may arise. To avoid this, turn and fluff the pile with a pitchfork often, perhaps weekly. You can also turn the pile by just re-piling it into a new pile. Wash hands after handling compost, or use gloves.

Size

Ideally, the compost pile should be at least three feet wide by three feet deep by three feet tall (one cubic yard). This size provides enough food and insulation for the organisms to live. However, piles can be larger or smaller and work just fine if managed well.

Composting Techniques

Composting can be done gourmet style, requiring more effort, with quick results--or can be done more casually.

  • Gourmet compost piles that have the right blend of nitrogen (greens) and carbon (browns) and are kept moist and fluffed regularly, will heat up to temperatures of 120 to 140 degrees Fahrenheit. The high temperature will kill most weed seeds and speed up the decomposition process so that the compost may be ready in 2 to 3 months or less.
  • Casual compost piles are also quite workable since compost will happen even if you just pile on yard and food waste, water sporadically, and wait. Since these piles don't get too hot, often worms will migrate into these and they will breakdown material. Casual composting can take several months.

If you are thinking about starting a compost pile in your backyard, you may want to familiarize yourself with the microbes that live in your compost pile.

How to Tell When it's Finished Compost

  • Compost is finished when the original material has been transformed into a uniform, dark brown, crumbly product with a pleasant, earthy aroma. There may be a few chunks of woody material left; these can be screened out and put back into a new pile.
  • You may want to stop adding to your compost pile after it gets to optimal size (about 3 cubic feet) and start a new pile so that your first pile can finish decomposing.

Give it a Try

Home composting is best learned by practicing. Through practice and observation you will find what works best for your home situation, and you can modify the process to suit your needs. For more information about composting, check with your local community or city for workshops, handouts, or guides on composting.

Backyard Composting Bins

Composting can be practiced in backyards in a homemade or manufactured composting bin or simply an open pile (some cities do require enclosed bins).

Typical homemade bins can be constructed out of scrap wood, chicken wire, snow fencing or even old garbage cans (with holes punched in the sides and bottom). For additional information on building your own bin, see CalRecycle's Building You Own Composting Bin: Designs for Your Community guide.

Manufactured bins include turning units, hoops, cones, and stacking bins. Take the time to consider your options and then select a bin that best fits your needs.

Troubleshooting a Backyard Composting Bin
Symptom Problem(s) Solution(s)
The pile smells bad Not enough air
OR
too much moisture
Turn the pile if not enough air

Add dry materials if too moist

The pile will not heat up Not enough moisture
OR
Pile size is too small
OR
Lack of nitrogen-rich material
OR
Particle size is too big
Add water if dry

Build pile to at least 3' x 3' x 3'

Mix in grass clippings or fruit/vegetable scraps

Chip or grind materials

The pile attracts flies, rodents, or pets Pile contains bones, meat, fatty or starchy foods, or animal manure Alter materials added to pile; bury fruit/vegetable scraps in the middle of the pile, or under 8" to 10" inches of soil, or compost them in a worm bin.
Pile has slugs in it (and so does garden) Pile is easily accessible and provides daytime hiding place and breeding ground for slugs Remove slugs and slug eggs from pile (eggs look like very small clusters of pearls). Locate compost pile far from vegetable gardens and/or create barriers around pile/garden (for example, traps and copper flashing).

Other Ways to Reduce Organic Waste

In addition to composting, you can also help reduce organic waste by grasscycling (leaving grass clippings on the lawn when you mow) and vermicomposting (composting with worms).

Food Scraps Management Home

Last updated: November 7, 2012
Organic Materials Management http://www.calrecycle.ca.gov/Organics/
Contacts: http://www.calrecycle.ca.gov/Organics/Contacts.htm