In terms of environmental efforts, community gardens foster a local food system that’s beneficial for both the wallets and the environment of their communities. Gardens are an environmentally sound mode of food production: large amounts of food can be grown in small areas, and the food doesn’t need to travel as far. In addition to reducing fossil fuel usage (it takes a lot less gas to transport a tomato down the street than to transport a tomato from Florida), it also has a much lesser environmental impact than large, industrial-style monoculture farms. Instead of depleting the soil year after year by planting the same crop, community gardens are diversified and can be shifted and rotated to the needs of the neighborhood—one is unlikely to see a community garden planted fencerow to fencerow with “Roundup Ready Corn” for twenty years straight.
Local food production also encourages local small business: large grocery chains find it hard to integrate produce from local farms, meaning that small businesses are given a better chance of success because their products are unique. A grocery store like Price Chopper (or even Whole Foods) is going to be much less adaptable to changing seasons and small producers; their supply chain necessarily demands large-scale and centralized production. Community gardens provide an incubator stage for small producers—people interested in growing their own food can learn from seasoned veterans in a relatively low-stress environment before striking out on their own. Access to agricultural knowledge is crucial to building a more sustainable food system, and community gardens provide a space for that knowledge to be transferred and gained.
Nonprofits like the Intervale Center in Burlington, Vermont provide a stepping stone between community gardens and small farmers by providing space for ‘incubator farms.’ There are community gardens throughout the area, but for those who are interested in turning their hobby into an occupation the Intervale Center lowers the barrier for entry by offering business planning, larger plots, and communal farm equipment. Through their incubator program, over 40 small farms have started throughout the Champlain Valley, providing a not-insignificant amount of produce for the area. These programs go hand in hand with community garden programs, and prove that the establishment of community gardens is a solid step towards the establishment of a sustainable, local food system.
 “Success Stories,” http://www.intervale.org/what-we-do/farms-program/success-stories/