UC Master Gardeners of Sonoma County
UC Master Gardener Program of Sonoma County

Compost for the Garden

Decomposition occurs naturally over time, affecting all organic matter. Managing the process for soil improvement in a compost pile provides rich organic material for the garden. It is a simple process, often likened to a recipe for baking a cake—combining the right ingredients in the right proportions under proper conditions.

Following a composting “recipe,” however, is only one method; yet, it is the route to generating a final product in the least amount of time. When there is no concern about time, a simple pile may be added to as materials are generated, then ignored. Eventually the collected organics will decompose and become compost.

Why Compost?

  • Recycle organic wastes generated in your home, landscape, and community.
  • Turn kitchen and garden residues, animal wastes, and woody materials into a rich and useful soil amendment.
  • Create a material that will improve structure, aeration, and drainage in all soil types.
  • Provide nutrients in compost that will be available to plants over a long period of time.

Build a Hot Pile

  • Make compost in only a few weeks using ingredients classified as carbohydrates and nitrogen, simply called greens and browns.
    • Reduce ingredients to small pieces—shredded or chopped.
    • Green ingredients are food wastes, plant residues, and manures.
    • Wood chips, dry leaves, paper products, and straw are examples of browns.
    • More greens than browns are needed to supply energy for the organisms that break down the pile. The ideal ratio is 30:1, generally achieved by using an equal volume of each.
    • Prevent lawn clippings and paper materials from matting by mixing them with dried ingredients.
  • Moisten the pile periodically to keep it as damp as a squeezed-out sponge.
  • Attempt to build the pile about 3 feet high and wide to generate and maintain heat created by microorganism activity.
  • Alternate greens and browns as you build the pile.
  • Turn the pile every few days to aerate and add moisture but avoid soggy conditions. Move materials in the outer edges to the center of the pile.
  • In cool or rainy weather, cover the pile to maintain heat.
  • High heat—best at 160 degrees F.—is needed for rapid decomposition and killing weed seeds. (Burr clover and cheeseweed seeds and oxalis bulbs are not killed.)
  • Continue to add easily decomposed nitrogenous materials such as food scraps when turning the pile.

Notes

  • Include other useful ingredients when available, such as urine—a sterile waste product—feathers, cotton or wool fabric, and hair.
  • Make compost with materials stacked in an open pile or layered in a bin.
  • Select a convenient, easy to access location for composting, optimally within the easy reach of a hose, out of wind and direct sun.
  • Do not include any ashes—they do not decompose—or manure from dogs and cats.
  • Avoid problems by keeping greens and browns in balance and by watering only as needed. Very dry piles slow down the process; excess moisture creates an odor.

Additional Information

When schools are open, we offer a program to Pre K-12th grade classes in Sonoma County.

  • We provide a worm bin to a classroom or a school garden.
  • We do an introductory lesson on worm composting and worm anatomy.
  • We provide additional curriculum for the teacher.
  • Call or email our Info Desk to reserve a space: 707-565-2608; mgsonoma@ucdavis.edu.

*Published with assistance from Zero Waste Sonoma

November 2022