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Classroom Resources

Compost Basics

Compost Basics

". . . by which dongyng and compostyng the feldes gladeth"
(William Caxton, pioneer 15th century printer)

According to the Environmental Protection Agency (EPA), 1/4 of the food bought in America ends up in the waste stream -32 million tons per year. Of that, less than 3 percent gets composted. The rest ends up in landfills, where it slowly rots, emitting methane, a greenhouse gas 21 times more potent than carbon dioxide. The EPA reports that wasted food in landfills accounts for 1/5 of US methane emissions, the second largest human-related source of methane in the US.

Composting is not complicated. It happens naturally, without any help from us. We can speed up the process, however, by balancing carbon-rich materials (Browns) with nitrogen-rich materials (Greens), by turning the compost pile regularly for aeration and by keeping the pile wet (but not too wet.) Below is a list of readily available materials that can go into a compost pile.

Greens (nitrogen-rich)

Browns (carbon-rich)

Ingredients not suitable for composting are oil, grease, bones, fat, dairy products and diseased plants.

Cold Compost Pile

A pile which is made up of greens and browns and then left alone to rot in place for several months to several years.

Hot or Active Compost Pile

A pile which is made up of greens and browns and then turned and aerated often to incorporate air, water, and/or fresh ingredients. Requires more effort but often results in finished compost within a several weeks to a few months.

Sheet Composting or "Lasagna" Bed

A specific sort of compost pile in which green and brown materials are built up in layers over a present or future garden bed site.

Pit or Trench Composting

A method where you bury organic material directly in the ground, sometimes along side of plantings, in a shallow trench.

How to Build a Sheet Compost Bed

  1. Mark the area for your garden using a water hose or a long rope to get the desired shape. Do NOT remove sod or weeds.
  2. Cover the area you've marked with wet newspapers or flattened cardboard boxes (available free from most large stores). This is your weed barrier.
  3. Cover the weed barrier with organic material—leaves, grass clippings, straw, wood chips, etc. Wood chips are often available free from your city's sanitation department.
  4. Layer several inches of organic material on top of the weed barrier. Make sure you balance greens
    • freshly cut grass
    • plant prunings
    • spent flowers
    • coffee grounds
    • kitchen scraps
    • barnyard animal manures (cow, horse, chicken, goat, sheep, and rabbit. NEVER use dog, cat, or human manure/feces as they may contain pathogens or diseases that could be harmful.)
    with browns
    • black and white newsprint
    • brown paper bags from grocery store
    • torn/shredded carboard (brown boxes, brown packing tubes, toilet paper and paper towel rolls, tubes egg cartons)
    • aged wood chips
    • sawdust from untreated lumber (check with a lumber yard)
    • straw
    • dried grass
    • dead leaves
  5. Water until the garden is the consistency of a damp sponge.
  6. Plant, plant, plant. Mulch, mulch, mulch.

Try it. It's easy.