Where gardens bloom amidst concrete and traffic

It's spring time in Germany, and in cities all around the country, apartment dwellers are digging in the dirt.

For Daniela Jovanovic, her small plot of flowers, vegetable rows, and grass is all she needs to disconnect from a numbing week at the factory and reconnect with the farm life she left behind in Serbia. She even spends some weekend nights in the garden's green-shuttered hut. "This garden is my life," she says. "It's good for my heart." Nestled among high rises and roaring traffic, her plot is one of more than 100 grouped into the "Bockenheim Neighborhood Small Garden Club."

In a longstanding tradition that sprung from an effort to combat the effects of industrialization, German law mandates that all cities set aside land for public use. Small and affordable, the Kleingartenkolonien – or small garden colonies – provide city dwellers with a bit of green space they can call their own.

This time of year, the country's 15,200 colonies – containing 1.3 million individual gardens – transform into a patchwork of colorful flowers and vegetables scattered along railway tracks or on "spare" pieces of land in the heart of cities. Each has its own personality, and the plots can be leased for a small fee (about $88 a year) and a promise to obey the rules.

In the Bockenheim [Frankfurt] club, for instance, a blackboard at the entrance tells members that pear, apricot, and cherry trees shouldn't be taller than 4 meters, and raspberry bushes no higher than 70 centimeters. Blackberry bushes must sit at least 1.5 meters from the border, and pesticides are forbidden.

The seeds of the tradition date to the 19th century, when industrialization pushed people into cities and a Leipzig teacher named Dr. Daniel Schreber suggested "paupers' gardens" as a way to help needy children escape basement apartments and keep men from bars.

When post-World War I housing shortages hit, people lived in self-made huts on their plots. And after the devastation of World War II, the gardens helped provide cities with produce. In communist East Germany, where fresh food was often rare, small gardens played a particularly important role, producing one-fourth of all fruits and vegetables.

Today, the law is the gardens' best friend. If a city takes over plots for building projects, it must find other spaces for the gardens. Depending on the individual city, it must set aside one plot of garden for every nine to 13 apartments.

Now, however, garden communities are at the crossroads of change. As young German families travel more, some no longer make time for garden responsibilities. "Today, life is more individualistic," says Heinrich David, president of the Small Garden Association in the state of Hesse, where Frankfurt sits. Increasingly, it's immigrants like Ms. Jovanovic who are assuring the healthy future of these gardens. The clubs, in turn, are helping foreigners ease into German society.

Demirezen Ayhan's garden sits next to Jovanovic's. Though Ms. Ayhan came from Turkey decades ago, as a guest worker, she says she didn't feel a part of Germany until she got her plot. She enjoys the community spirit here – the restaurant, the annual picnic, the garden contest. "We have our peace here," says Ayhan. "Our neighbors are good people."