This post is from one of the 16 interns in the Real Time Farms Food Warrior Summer Internship Program (our Fall 2011 Food Warriors will be starting soon!). These interns are collect data, pictures, and video on the growing practices of our nation’s farms, collect food artisans’ stories, and document farmers markets. We all deserve to know where our food comes from!

While visiting a friend in San Francisco recently, I was surprised when while making dinner, I saw her grab our leftover scraps of vegetables and toss them into a small green bin next her sink. Composting is far from an unfamiliar concept to me, but what surprised me was that the bin was provided to her by her city, and that San Francisco requires all properties in the city to compost leftover food and garden debris. Thanks to systems like this, San Francisco is actually the greenest city in North America.

In 2009 the city of San Francisco created the first large-scale urban composting system in the country. They provide each residential property with both a small bin, designed to go in kitchens, and a larger bin, to put all the compost in to be collected weekly, along with recycling and trash. Acceptable green waste includes food scraps (described as anything that used to be alive), food-soiled paper (such as coffee filters, greasy pizza boxes, and used paper cups and plates), and plants (including branches, flowers, leaves, grasses and weeds).

The materials are sent to Recology’s Jepson-Prairie compost facility located in Vacaville, California, and the company collects about 540 tons of food scraps and plants daily. This creates about 95,000 cubic yards of nutrient-rich soil, which is then sold to farms and vineyards in Northern California and is used to produce the organic food and wine that this region is so famous for having.

There are numerous environmental benefits to composting. The organic soil that results from composting reduces the need for fertilizers and pesticides, and it also helps the farmland retain water, so less irrigation is needed. Composting also reduces landfill waste and methane emissions, and recent research has also shown that the increase in composting in San Francisco has decreased carbon emissions in the area drastically. Recology’s compost is frequently used to help grow crops that help farms manage soil quality, and these crops draw carbon in from the air, and the carbon is deposited deep into the soil by the roots of these plants. According to Recology’s public relations manager, using compost on one acre of land can eliminate 12,000 pounds of carbon in one year. This means that San Francisco’s composting offsets their carbon emissions by 354,000 metric tons.

Going by those numbers alone, it seems surprising that more cities in the United States haven’t adopted this composting system. Research has shown that, in 2008, Americans generated about 32 million tons of food waste, but less than 3 percent of that was composted. Cities like Seattle have made steps to adopt successful compost systems as well, but there are still numerous other cities that could pull off a system like San Francisco’s.

Maddy Kiefer

Summer 2011 LA Food Warrior Intern