A city's community gardens can be as diverse as its communities of gardeners. Some choose to solely grow flowers, others are nurtured communally and their bounty shared, some have individual plots for personal use, while others are equipped with raised beds for disabled gardeners.
Community gardens encourage an urban community's food security, allowing citizens to grow their own food or for others to donate what they have grown.The gardens also combat two forms of alienation that plague modern urban life, by bringing urban gardeners closer in touch with the source of their food, and by breaking down isolation by creating a social community. It has also been found that active communities experience less crime and vandalism.
Like traditional public parks, most community gardens are open to the public, and provide green space in urban areas, along with opportunities for social gatherings, beautification, education and recreation. However, in a key difference, community gardens are managed and maintained with the active participation of the gardeners themselves, rather than tended only by a professional staff. A second difference is food production: Unlike parks, where plantings are ornamental (or more recently ecological), community gardens often encourage food production by providing gardeners a place to grow vegetables and other crops. To facilitate this, a community garden may be divided into individual plots or tended in a communal fashion, depending on the size and quality of a garden and the members involved.
Community gardens vary widely throughout the world. In North America, community gardens range from familiar "victory garden" areas where people grow small plots of vegetables, to large "greening" projects to preserve natural areas, to tiny street beautification planters on urban street corners. In Europe, closely related "allotment gardens" can have dozens of plots, each measuring hundreds of square meters and rented by the same family for generations. In the developing world, commonly held land for small gardens is a familiar part of the landscape, even in urban areas, where they may function as mini-truck farms.
For all their diversity, however, most community gardens share at least four elements in common: Land (or a place to grow something); plantings; gardeners; and some sort of organizing arrangements.
Land for a community garden can be publicly or privately held. One strong tradition in American community gardening in urban areas is cleaning up abandoned vacant lots and turning them into productive gardens. Alternatively, community gardens can be seen as a health or recreational amenity and included in public parks, similar to ball fields or playgrounds. Historically, community gardens have also served to provide food during wartime or periods of economic depression. Access to land and security of land tenure remains a major challenge for community gardeners and their supporters throughout the world, since in most cases the gardeners themselves do not own or control the land directly.
Two national surveys sponsored by the American Community Gardening Association in the late 1980s and mid-1990s, and other research, strongly support the observation that there is no "standard" community garden plot size, at least in the United States and Canada. Individual plot sizes vary widely depending on many factors, including location, land available for gardening, demand, physical and time limitations of the gardeners, among others. As a general rule, North American community garden plots so tend to be smaller than European allotments. 6m × 6m (20ft × 20ft) is one common plot size (larger gardens in parks); 3m × 3m (10ft × 10 ft) or 3m × 4.5 m (10 ft × 15 ft) is another (inner city gardens on small lots).
While food production is central to many community and allotment gardens, not all have vegetables as a main focus. Restoration of natural areas and native plant gardens are also popular, as are "art" gardens. Many gardens have several different planting elements, and combine plots with such projects as small orchards, herbs and butterfly gardens. Individual plots can become "virtual" backyards, each highly diverse, creating a "quilt" of flowers, vegetables and folk art.
Gardeners may form a grassroots group to initiate the garden, such as the Green Guerrillas of New York City, or a garden may be organized "top down" by a municipal agency. The community gardening movement in North American prides itself on being inclusive, diverse, pro-democracy, and supportive of community involvement. Gardeners may be of any cultural background, young or old, new gardeners or seasoned growers, rich or poor. A garden may have only a few people active, or hundreds.
Finally, all community gardens have a structure. The organization depends in part on whether the garden is "top down" or "grassroots". There are many different organizational models in use for community gardens. Some elect boards in a democratic fashion, while others can be run by appointed officials. Some are managed by a Non-profit organizations, such as a community gardening association, a church, or other land-owner; others by a city's recreation or parks department, a school or University. In most cases, gardeners are expected to pay annual dues to help with garden upkeep, and the organization must manage these fees. The tasks in a community garden are endless - keeping up the area's appearance, mulching paths, recruiting new members, reminding members to tend plots when they get weedy, fundraising, the list goes on... Sensible rules and an 'operations manual' are both invaluable tools, and ideas for both are available at ACGA and other sites.