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Guide to effective composting

Tools for living    Natural gardening    Composting guide

Learn how you can save money and reduce waste by composting certain food scraps and yard waste. See information on different methods, and read about easy solutions to composting problems.

compost bin

Composting is easy and inexpensive and the resulting mix will help your garden grow healthy and strong. Finished compost is a dark, crumbly mixture of decomposed organic matter and you can use it to control weeds, provide nutrients to plants, improve soil and save water.

Composting methods

There are several composting methods - select the option that works best for you...More

Composting problems and solutions

Simple steps to speed up composting, eliminate odors and keep away pests...More

Composting with worms

Want a compact, easy way to turn fruit and vegetable scraps into food for your plants? A worm bin is the answer...More

Buy a value-priced compost bin

Metro now offers two different value-priced compost bins to turn food and yard waste into gardeners' gold...More

Composting demonstration sites

Open to the public every day for self-guided tours, these demonstration sites feature active household-scale composters, worm bins and other information...More

Uses for compost

While it is not a substitute for fertilizer, compost contains nutrients and holds them in the soil until plants can use them. It also loosens and aerates clay soils, and retains water in sandy soils. Here are some common ways to use finished compost:

  • Soil amendment: Mix 2 to 5 inches of compost into vegetable and flower gardens each year before planting.
  • Potting mixture: Add one part compost to two parts commercial potting soil, or make your own mixture by using equal parts of compost and sand or perlite.
  • Mulch: Spread an inch or two of compost around annual flowers and vegetables, and up to 6 inches around trees and shrubs.
  • Top dressing for lawn: Mix finely sifted compost with sand and sprinkle evenly over lawns.

Recipes for success

A compost pile is a teeming community of micro-organisms that help break down yard debris into compost. Help speed up the composting process by following Metro's recipes for success:

  • Two parts brown to one part green
    The best mix of nutrients for the microorganisms is two parts carbon-rich "brown" materials, such as dried leaves, mixed with one part nitrogen-rich "green" materials, such as grass clippings. A compost pile with these proportions of brown to green will promote large populations of microorganisms that will heat up yard debris and produce compost quickly. Other proportions of brown to green will create good compost, but will decompose more slowly.
  • Air and water
    Most life on earth needs a certain amount of water and air to survive. The microorganisms in the compost pile function best when the materials are as damp as a wrung-out sponge and have many air passages. Extremes of sun or rain can adversely affect the balance of air and moisture in your pile. The air in the pile is usually used up faster than the moisture, so the materials must be "turned" or mixed up occasionally to add air that will sustain high temperatures and control odor.
  • Chop it small
    Smaller pieces of material compost faster. Chop garden debris with shears or a machete, or use a chipper-shredder or lawn mower to shred material.
  • Size matters
    Compost piles trap heat generated by the activity of millions of microorganisms. A 3-foot square compost pile is considered a minimum size for hot, fast composting. Piles wider or taller than 5 feet don't allow enough air to reach the center.
  • Time and temperature
    The most efficient decomposing bacteria thrive in temperatures between 110 degrees and 160 degrees Fahrenheit. Thus, the hotter the pile, the faster the composting. If you achieve a good balance of carbon and nitrogen, provide lots of surface area within a large volume of material, and maintain adequate moisture and aeration, the temperature will rise over several days.

Download brochure or bin plans

View plans for building a three bin composting system or a basic wood and wire compost bin. The 16-page composting booklet includes what to compost and how to do it, different methods and uses, ideas for yard debris, grasscycling, and solving common problems.

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Portland composts food scraps

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Portland residents can throw food scraps in their green roll cart. Fruit, vegetables, meat and dairy products are all fit for pickup. Find out more at Portland Composts! Go

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Find eco-friendly businesses at and accredited organic yard care at to help you grow green.

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It's easy to make your own compost

Composting is easy and fun and will help you grow a strong, beautiful garden. Even the first-time composter can make quality compost. Use this guide to help you get started. Download the PDF

Did you know?

Metro's online calendar shows a full listing of all Metro natural gardening events, plus other natural gardening events from around the region.

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