Most of us know the gist of composting. Organic waste naturally decays, creating a material rich in the minerals and nutrients that make healthy soil. But while gardeners across Seattle have been turning food scraps into fertilizer for years, few of us know exactly how important composting can be.

According to the EPA, yard waste and food scraps make up nearly one-fourth of the trash generated in the United States. No big deal, since it's biodegradable, right? Wrong. In a landfill, which is an anaerobic environment (there's no oxygen), the rate of decomposition can be up to 100 times slower than under natural conditions, even for a banana peel.

When organic material does break down under these conditions, it generates greenhouse gases like CO2 and methane. In fact, landfills are the largest source of human-related methane emissions in the United States.

Composting is a simple but perfect solution that keeps waste out of landfills while creating humus that'll help any garden grow. In addition to feeding plants, composted material can help prevent erosion, remove volatile organic compounds from contaminated soil, and reduce concentrations of toxic heavy metals.

It's all around town: Seattle's food banks are starting a composting program, and all dining areas and kitchens at the University of Washington now feature composting systems. UW cafeterias use biodegradable corn-based cutlery and food containers made of sugar cane and straw, so that all table scraps can be collected and sent to Cedar Grove Composting in Everett. The aim, according to the student newspaper, is to "reduce the waste stream down to a trickle." 

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