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Composting Basics

Man shoveling compost

Composting is the process of helping turning "waste" into an earthy smelling material that's like a multivitamin for your garden soil. Compost helps improve your soil structure and water holding capacity, promotes soil fertility, stimulates healthy root development and aids in erosion control. 

However, many gardeners often feel confused about the composting process. Here are some FAQ's and their answers.

Veg scraps in compost bin pixabay

What can I compost?

  • Kitchen: fruit and vegetable scraps, tea bags, coffee grounds, and eggshells.
  • Yard waste: grass clippings (except Bermudagrass), leaves, pine needles, and shredded wood chips.
  • Rotted manures from non-meat-eating animals are allowed, but not necessary.

What shouldn’t I compost?

  • Avoid animal products (meat, bones, fish, grease, dairy).
    turning fork
  • Ashes from the fireplace or BBQ (can cause pH imbalance in soil).
  • Sawdust from treated wood.
  • Dirt: this ends up making it heavy and too hard to turn.
  • Avoid diseased plants.
  • Weeds that have gone to seed, Bermudagrass.

What are “greens” and “browns?”

Greens are moist and rich with nitrogen and include vegetable & fruit scraps, grass clippings, coffee grounds, and rotted manures.

Browns are dry and carbon rich, and include dry leaves, straw, sawdust, wood chips, corn stalks, cardboard, and paper.

How much greens and browns do I need?

When building a pile, you need to add equal amounts of greens and browns. The easiest way to do this is by using two 5-gallon buckets.

Please watch our presentation and download the Composting Basics handout to follow along. You'll learn what compost system to choose, which compost method to use, how often to turn your pile, pests, troubleshooting, and a general demystification of the composting process.

For more resources, you can access the following UC ANR publications:

Compost in a Hurry
Composting is Good for You and the Environment


Presentation recording coming in 2021! In the meantime, read about vermicomposting, the process of composting kitchen waste with worms at https://ucanr.edu/sites/sacmg/files/153018.pdf