Composting

Turn household vegetative waste into fertilizer. All organic matter eventually decomposes. Composting speeds the process by providing an ideal environment for bacteria and other decomposing micro-organisms. The final product, compost, looks and feels like fertile garden soil. This dark, crumbly, earthysmelling stuff works wonders on all kinds of soil and provides vital nutrients to help plants grow and look better. Decomposing microorganisms need four key elements to thrive: nitrogen, carbon, moisture, and oxygen. For best results, mix materials high in nitrogen (such as clover and fresh grass clippings) and those high in carbon (such as dried leaves and twigs). Moisture is provided by rain, but you may need to water the pile to keep it damp. Be careful not to saturate the pile, use a cover to prevent saturation. Oxygen is supplied by turning or mixing the pile. More turning yields faster decomposition.

Getting started

Many materials can be added to a compost pile, including leaves, grass clippings, straw, woody brush, vegetable and fruit scraps, coffee grounds, sawdust (excluding sawdust from treated lumber), and shredded paper. Avoid using meat scraps that attract animals, and dog or cat manure which can carry disease. Composting can be as simple or as involved as you would like, and depends on how much yard waste you have, how fast you want results, and the effort you’re willing to invest.

Cold composting

With this method, you can add grass clippings and dry leaves on the ground or in a bin. It requires no maintenance, but you’ll have to wait several months for the pile to decompose. This works well if you’re short on time or have little yard waste. Keep weeds and diseased plants out of the mix. Add yard waste as it accumulates.

Hot composting

This requires more work, but with a few minutes a day and the right ingredients you can have finished compost in a few weeks. Hot piles must be built all at once in a four to five foot cube and turned regularly. As decomposition occurs, the pile will shrink. A three foot cube is needed to maintain necessary heat. Hot piles can reach 110 to 160 degrees Fahrenheit, killing most weed seeds and plant diseases. On a level site, lay down bricks or prunings to promote air circulation. Spread several inches of the high-carbon material, then mix high-carbon and high-nitrogen material together. Water periodically. Punch holes in the sides of the pile for aeration. The pile will heat up and then begin to cool. Start turning when the pile’s temperature begins to drop. Move materials from the center to the outside and vice versa. Turn every day or two and you should get compost in less than four weeks. Turning every other week will give compost in one to three months. Finished compost will smell sweet and be cool and crumbly to the touch.

Additional Resources

Source: "Hawaii Backyard Conservation" (PDF), The U.S. Department of Agriculture.

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