Of course, not all city property is best saved for farming -- at least, according to officials in Seattle.
Recently, the city's transportation department has taken pains to discourage people from planting crops on city-owned strips of land alongside highways and suburban roadways.
The city provides permits to people seeking to grow plants on such land, but Department of Transportation spokesman Rick Sheridan said that officials worry that food plants there might fall prey to contamination from automobile exhaust and storm water runoff.
"We're supportive of the idea of people growing crops for themselves," he said, but "not all land is necessarily the best land for urban farming."
Even if fumes and contamination aren't an issue, growing your own food in a city or elsewhere isn't easy.
Openlands, a nonprofit group that works to preserve open space in northern Illinois, offers urban agriculture classes every winter. Classes focusing on growing edible plants are the most popular, said Jamie Zaplatosch, Openlands' education coordinator.
Food plants, Zaplatosch said, can be more temperamental, especially in northern cities where growing seasons are less than ideal. Would-be urban growers learn which time is the best for planting different plants -- spinach, for instance, can be planted in the springtime, while tomatoes should wait until June -- and various gardening techniques.
"We're getting a lot of people in the city really interested in getting the most out of their small urban spaces as they can," Zaplatosch said.
In some cases, it's more than just the gardener who reaps the rewards of community gardens.
The nonprofit group Urban Farming has established some 500 gardens in Detroit and more in other cities across the country. The gardens, said executive director Taja Sevelle, are "borderless" and maintained by volunteers, ranging from retirees to church youth groups. Anyone, she said, can walk on to the gardens to harvest and pick food.
About half of the food grown at Urban Farming's gardens, Sevelle said, is picked by local residents, while the rest is donated to food pantries.
Sevelle thinks of the gardens as a throwback to the old Victory Gardens of the 1940s, when Americans grew food in their backyards to supplement the nation's food supply during a time of war.
"Our goal is to get rid of hunger in our generation," Sevelle said.
"We've had people come to us crying more than once on these gardens and thanking us," she said, "but this year, it's even deeper because food prices have gone up."
Detroit resident Cynthia Johnson, 55, is among those grateful for the gardens. Johnson volunteers at an Urban Farming garden right near her home, and already has plans to eventually make dinner out of what she's helping to plant this season.
"I think it's very inspiring," she said. "To know that you can come to a garden and pick food if you need it, without penalty, is a blessing."