Composting

Reduce food waste and greenhouse gas emissions while building healthy soil by composting.

Did you know that when food waste decomposes in a landfill it releases methane, a greenhouse gas 20 times more potent than carbon dioxide? By instead composting food waste, yard trimmings, and other biodegradable items like paper we can create high quality fertilizer for our plants, reduce greenhouse gas emissions, and build soil health, which in turn sequesters carbon!

 

OPPORTUNITIES

96% of food that could be composted ends up in the landfill, and compostable materials comprise roughly 41% of landfills in California according to Californians Against Waste. Compost reduces the need for new landfills, eliminates a source of greenhouse gas emissions, helps sequester carbon when added to soil, and provides locally sourced fertilizer for plants that need it.

SIMPLE COMPOSTER DESIGNS
  • Mesh Ring: Create a 3 foot round mesh circle with 10 feet of hardware cloth, connecting the ends together. If you like, use 3-4 T posts to hold the wire ring in place, and fill it with compost.
  • Shipping Pallets: Gather 4 shipping pallets. Be sure that the stamp on them reads HT - for heat treated, rather than MB, which stands for methyl bromide, something we don't want in the garden. Screw three pallets together to create a back and two sides of a square, use a rope or wire to create a front that can be removed to turn the pile. Expand this to a 3 bin system where you store cover material like extra leaves in the first bin, have an active pile in your second bin, and leave the third bin for finished compost ready for the garden.
  • Cinderblock: Use cinderblock or brick to create a structure similar to what was described above. Be sure that your cinderblock square is at least 3 feet wide, and 3 feet deep so that your compost has enough mass to heat up and kill weed seeds or any potential pathogens.

 

BUILDING THE PILE:
  1. All compost requires the same 4 basic ingredients: Air, water, carbon (browns) and nitrogen (greens).
    • Browns: Carbon material or "browns" are biodegradable materials that you could sit out on your counter for a week without it smelling funky.  Newspaper, sawdust, leaves, corn husks, and woodchips are all examples of a "brown".
    • Greens: "Greens" are biodegradable materials that have a higher nitrogen content. These are things like fruits and vegetable scraps, fresh grass clippings and chicken manure.
  2. In your chosen composting container, layer greens and browns together, always covering the pile with leaves, mulch, or another brown material to avoid attracting pests.
    • Air: Your compost pile should not be heavily compacted - bacteria and fungi that do the work of composting need to breathe.
    • Water: As you layer your greens and browns together, ensure that the pile is moist enough to keep the fungi and bacteria alive. In some climates, not much is needed to make that happen. In others, its important to turn and water your compost pile regularly. In desert climates it may make sense to tarp compost to keep it moist.
  3. Turn your compost with a pitchfork, moving it around after a resting period of your choosing. Some people turn their compost every two or three days. Others once every 6 months, or only when they need to harvest compost for the garden. Some people screen their compost with hardware cloth to keep larger pieces of wood and sticks out. Others are unbothered by some additional organic material continuing to decompose in the garden.
COMPOST DON'TS
  1. Don't compost salty food scraps, weeds with seeds, Bermuda grass if you are trying to eliminate it, pet waste, or obviously non-biodegradable materials like polyester clothing, plastic, rubber, or produce stickers.
  2. Don't add only food scraps, the pile will begin to smell like anarobic bacteria, which is to say it will smell awful. Compost needs browns and greens together to be balanced.
COMPOST DO'S
  1. Consider gathering food scraps in a kitchen bin, and taking it to add to your compost pile at the end of a cooking session.
  2. Chop yard waste into small pieces, no larger than a foot. 6 inches is a good size for most small branches and twigs.
  3. Check on your pile using a compost thermometer, or your hand. If the pile is emitting heat, it's actively breaking down. When it cools, decomposition has slowed and it could use turning to introduce more air, water, and to mix brown and green elements together.
  4. Locate your compost in a shady area that is not too far from your kitchen door.
  5. Alternatively, locate your compost pile where you will need it delivered, in your garden, near fruit trees, etc.
RESOURCES:

EPA's Guide to Worm Composting: For apartment dwellers or renters, vermicomposting or worm composting with red wriggler worms offers a solution.

USDA Backyard Composting Tip Sheet: A overview with a bit more detail about composting