The nonprofit San Francisco Planning + Urban Research Association (SPUR) was instrumental in pushing for the legislation [PDF], which Upton notes, "follows zoning changes last year that made it easier to operate small farms and legal to sell food grown in San Francisco. This new set of laws will take it further by removing additional bureaucratic barriers for hopeful gardeners and actively searching for land they can use while providing them with seeds, tools, and advice."
The legislation establishes an Urban Agriculture Program for the city and county of San Francisco, that, "will audit city-owned land and rooftops in a quest to dig up potential new public gardening sites. It will also develop incentives for owners of vacant lots to allow their land to be used for community farming."
"San Francisco's adoption of the new urban farming programs follows a trend that has seen Detroit, Portland, Baltimore, New York, Seattle, Oakland, and other major cities craft programs and laws in recent years to encourage agriculture and gardening within city limits," notes Upton.