DNRP > SWD > Composting & Soils > Composting

Composting

Compost is a natural organic material that is produced when leaves, plant residue, grass clippings and other yard waste break down over time.

Organic materials decompose in nature to feed soil and make it healthy. You can imitate nature in your own yard by composting your yard waste and kitchen waste. Compost is used as a soil amendment rather than a fertilizer because its nutrients become available slowly. Worm castings, is a nutrient rich top dressing and soil amendment, which provide nutrients for your plants in a form the plants can use as needed. Apply two to three inches of worm castings to your soil as a top dressing in small areas of your garden to feed the plants and nurture their growth.

You can buy compost and worm castings or make your own:

• Buy bagged compost and worm castings during the Northwest Natural Yard Days promotion
• Buy a compost bin online (external)
  King County Solid Waste Division sponsors online compost bin sales for up to 29% off retail prices. The compost bin sales are offered year-round.

Benefits of Composting

• Encourages the growth of earthworms and other macro-organisms, whose tunneling makes room for water and air
• Provides nitrogen, phosphorus, potassium, sulfur and micro-organisms that are essential for plant growth
• Acts as a glue, holding water and soil particles together, and makes soil resistant to erosion
• Binds itself to polluting metals, pesticides and other contaminants to prevent them from washing into waterways or being absorbed by plants
• Suppresses soil-borne diseases and plant pathogens (a number of plant and lawn diseases are suppressed by micro-organisms found in compost)

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