In a quiet neighborhood in Berkeley, California, there is a handmade iron gate so beautiful, with whimsically wrought dragonflies and arcing sunflower patterns, you don't even mind being locked out. You get the sense that a secret password rather than a key would open it. Behind the gate (which is unlocked during the frequent visiting hours), a community garden flourishes. Members navigate the terrain on gravel paths wide enough for wheelchairs. As they work, either in their own allotted plots or in the communal space that contains endangered and threatened native plants and flowers, a fountain powered by the sun provides a trickling soundtrack. On the morning I visit, sagey smells of native salvia waft by with bits of conversation from gardeners harvesting winter vegetables, while a little kid with sandy curls and rosy cheeks points at a coveted lettuce leaf she'd like permission to pick.

When garden regular Karl Linn spies 18-month-old Kyla Rain tromping toward her mom with a kid-size plastic trowel in hand, he breaks into an avuncular smile. "She's the most important thing growing here," the 78-year-old says.

Much of the Peralta Community Garden is perched near the yawning mouth of a Bay Area Rapid Transit (BART) tunnel in the neighborhood of North Berkeley. When trains swoosh by, they temporarily drown out the birds and force gardeners to either stop talking or yell to be heard above the din. For years the strangely shaped piece of BART-owned land was fenced off with barbed wire, accumulating weeds and junk. Linn had spotted the property as he worked across the street at another once-blighted plot-now the Karl Linn Community Garden, dedicated in his name at a surprise 70th birthday celebration honoring his lifelong dedication to putting beauty and nature back into cities. After the ceremony, Linn and others got the city of Berkeley, which owns the property, to pony up $10,000 for building materials; then they spent nearly two years making it into a vibrant community garden with 15 individual plots. Today, a small shed in the garden serves as a demonstration station for sustainable ecological innovations. Its green roof sprouts various kinds of succulents, while a cutaway in the wall reveals its adobe-like "cob" construction of earth, sand, and straw.

From North Berkeley to the South Bronx, Linn has seen latent beauty in urban blight. A landscape architect, educator, and psychotherapist, he has transformed his vision into activism, helping create garden "commons" in redlined as well as tree-lined neighborhoods from coast to coast. "One can always turn a liability into an asset," says Linn in a thick German accent from beneath his floppy green gardening hat. It's hard to argue with his optimism-coming as it does from a man who survived Nazi persecution and exile-or with his success.

Linn was born in 1923 to the only Jewish family in the tiny village of Dessow in northern Germany. He grew up on a tree farm-an accredited training center for gardening and "horticultural therapy" that his mother established in 1910. Students would mingle with the mentally ill, and all tended the orchard's 2,000 cherry, apple, plum, and pear trees. Emphasizing digging in the dirt rather than into the psyche, horticultural therapy is one of the oldest healing arts, with benefits not restricted to the sick. "Growing up as an only child I established a deep ecological connection with whatever natural elements and creatures were around me," Linn remembers. "I had wonderful relationships with cats and dogs, mother hens and trees. They were my companions and my source of inspiration and peace-all contributing to my mental health-and remain so to this very day." Linn adds that since all the adults in his life were careful farmers, tilling the land responsibly has also remained important to him.

Linn's idyllic childhood came to a crushing end with the rise of Hitler; his family's stewardship of the land and good standing in the community were unable to protect them from German soldiers. "Our house was a mile up the road from the village and we could hear the Nazis marching in goose-step on the cobblestones," recalls Linn. "Even now, when I hear ladies in high heels on pavement, I experience a shock." His family lost their orchards but saved their lives. They escaped to Palestine in 1934 and settled a new farm, which the young Linn began managing at the age of 14, after his parents became too sick to work. "I enjoyed growing plants but I couldn't stand harvest time-the fields looked plundered," Linn remembers. "I yearned to grow plants and let them unfold in their own beauty."

Linn attended agricultural school and concentrated on the study of ornamental horticulture. After graduating he cofounded a kibbutz, working with others to transform deserts into green pastures and orchards. "It was during this time that I began to see the importance of creating places for privacy and contemplation but also for community participation," says Linn. "Places where young and old could be in each other's presence but not in each other's way."

He also began to feel a need-stemming from his early experience with Hitler's Germany and growing alarm at the way Arabs were being treated in Palestine-to explore human nature and relationships more deeply. In 1946, at the age of 23, he left his adopted homeland to study psychoanalysis in Switzerland. As a displaced person-born to a place he loved and then forced into exile-Linn probed the social, psychological, and ecological dynamics of feeling rooted. From Zurich, he immigrated to New York, where he built successful practices in both child psychoanalysis and landscape architecture.

After several years working on the yards of wealthy suburban clients on the East Coast, Linn had a Betty Friedan moment in the 1950s and realized how cut off women and children were in the suburban nuclear-family. "The suburbs were designed with the male breadwinner in mind," says Linn. "Men wanted peace and quiet when they returned from the city, so everything was designed for isolation. There were no benches where women could sit and talk; no playgrounds close by; and often no sidewalks, just cars. It was like a green desert." Frustrated with creating disconnected havens of affluence, Linn started teaching landscape architecture at the University of Pennsylvania, drafting his students to work in low-income areas to build what he calls "neighborhood commons"-communal spaces that bring neighbors together.

The idea of a commons is key to understanding Linn's work. In a 1999 article for New Village magazine, he argues that an inherently sacred relationship exists between living creatures and nature. "From time immemorial," writes Linn, "people of indigenous or land-based cultures have celebrated their connectedness with nature as an integral part of their daily lives. Free and enduring access to air, water, and land assured their sustenance and survival." According to Linn, urban community gardens are the last remnants of the commons in contemporary life.

Though Linn was popular with the students he taught at the School of Fine Arts in Philadelphia, the dean was not a fan. At the time, most U.S. institutions had only begun to acknowledge their role in perpetuating racism and segregation, and arts administrators did not smile upon a man who encouraged his white students to leave the ivory tower to work with people in what were then called slums. When told he was confusing social work with art, Linn ignored his detractors. Students and residents planted greenery; salvaged lumber, old brick, and even marble steps from buildings slated for demolition; and built playgrounds for kids and gathering spots for adults.

One of Linn's defenders was Louis Kahn, a fellow professor and world-renowned architect. In a 1963 letter to the dean, Kahn wrote: "Having recognized the signs of a new way of life, [Linn's] efforts are designed to reconstruct a concept of the usefulness of man and his role as a contributor to the community of men. This is in tune with the will to create . . . and would be one of the phases of a declared war against the waste of human wonderfulness and the waste of material and economic means." Linn smiles as he recalls that after Kahn's letter, the university brass left him alone.

It was in Philadelphia that Linn met a 21-year-old African American named Carl Anthony. At the time, Anthony was a high school dropout working with a cultural center called Heritage House. "The organization had just been given a building with a great courtyard," says Anthony, an architect and activist who now lives in Oakland, California. "And here comes this short little guy talking with a serious accent, his students in tow, offering to provide some technical assistance and design proposals for the courtyard." The two men struck up a friendship that has lasted more than 40 years.

"In high school I had studied architectural drafting," Anthony says. "When I met Karl I was trying to make a connection between urban design and the struggle of black people for human rights." The two men would spend hours walking the back alleys of Philadelphia, the older Karl talking to the younger Carl about what he saw as the human, spiritual, and ecological dimensions of urban design. "He taught me how to see," Anthony says matter-of-factly. "He'd describe his love for this tree that grew all over North Philadelphia, the ailanthus-something I'd always considered a big weed. He actually helped me see how the trees, their patterns of growth, and the neighborhood architecture created a powerful visual character."

Linn got Anthony involved in one of his neighborhood commons projects. "There was a little alleyway behind a vacant lot," remembers Anthony. "It was right across from a women's prison. Karl got the neighbors to each bring an old dinner plate from home and made this incredible event out of smashing plates and then using the pieces to pave the alley. They made the most beautiful mosaic I've ever seen." Most of these neighborhoods were considered beyond help, says Anthony. "They'd been declared blighted by the development agencies, and all the city wanted to do was tear everything up and clear people out. To me what was so wonderful was the way Karl participated in celebrating what people had."

"What Karl has always insisted upon," Anthony says, "is that people have the capacity to spontaneously transform their environment with very few means. I've always been kind of irritated at that idea." It's been an ongoing yet collegial conflict between them: Linn emphasizing the right to beauty and the ability to create it anywhere, anytime; Anthony giving a higher priority to the slow work of changing the social and economic conditions of minority communities. "My sense has always been that you have to raise an army before you can fight a war," says Anthony, referring to his emphasis on traditional political activism.

"Karl always responds, 'No. Let's change the world now!'"

Carl Anthony went on to study architecture at Columbia University. In 1989, the two men joined forces again, cofounding the Urban Habitat program at Earth Island Institute in San Francisco. "Karl and I started having conversations long into the night, rekindling our arguments about beauty and social justice. We concluded that we could fight for both." Anthony continues, "In spite of everything-that the city is paved over, that there are miles upon miles of mind-numbingly ugly buildings, pollution, and all the things that make city life so difficult-Karl has asserted his connection to life, to beauty, to being, and has encouraged this celebration in others."

Linn is more down-to-earth about his passions. "The essence of my work is awakening the commons and the spirit of community," he tells me as we tour Northside, a third garden he helped set up alongside the Peralta and Karl Linn oases in North Berkeley, where he retired in 1987. "For me, this kind of spirit is the basis for democracy-it encourages vital neighborhoods."

Northside's 16 individual plots, like Peralta's 30, are on BART-owned land. Once the area was an eyesore in an otherwise well-maintained mixed-income neighborhood where tenants live in apartments next to private homes with fenced-in yards. Like 90 percent of the more than 10,000 community gardens nationwide, these exist on a temporary basis. Seattle is currently the only city with community garden allotments written into its general plan. Linn and others are now working to insert a similar clause into the general plan for Berkeley, where a tight housing market and increasing property values make open space especially vulnerable. In the New York City area, for example, 20 community gardens were bulldozed in 1997, and the city agency that administers the garden leasing program has been directed not to issue or renew long-term leases. The land is too valuable, say agency representatives, and new housing developments are needed. This Giuliani-esque attitude goes against the city's own open-space plan, first authorized in 1990, which states that the preservation of community gardens is a critical part of providing equity for urban populations chronically and severely short of open space. "Lands, which in an urban area can be used for community gardens . . . are as significant to the environmental health of city residents as areas in pristine environmental condition are to people in rural areas," the plan states.

Impermanence was built into the BART lease for the Peralta and Northside Community Gardens: It stipulates among other things that only temporary structures can be built. At first, the gardeners worked to honor this condition. For instance, when artist Dmitry Grudsky volunteered his considerable talents to design a GaudĄ-like mosaic bench, he and volunteers tried to construct it in segments. But after a while they gave up and instead built one long, curving, and absolutely immovable beauty of a bench, with mosaic pieces that pick up the seasonal colors of the plants growing around them. A similar dynamic happened with a tool shed. It started out on blocks, but then somehow took root over the two years of construction with volunteer labor. "It's sometimes easier to ask forgiveness than permission," says Linn with a conspiratorial smile. He's not as worried about being displaced as he once was. "After the director of BART real estate brought his staff here for a picnic, they became community-garden converts," he says. BART had been criticized for decades for allowing its Berkeley lots to fill with weeds and junk; now the area is a neighborhood highlight.

Alongside its individual plots, the Peralta garden has communal beds planted with butterfly-attracting plants and native California flowers and shrubs. Carol Bennett-Simmons, a Berkeley grade school teacher, was instrumental in designing the commons area. "For me, the design process had a lot to do with creating habitat for the creatures that have evolved with the native plants," says Bennett-Simmons. She notes that it took a while for the butterflies, bees, and birds to locate their ecological mates, but with each season she's seeing more flutterings.

Gardener Mike Menning knew next to nothing about plants before he got involved with the Peralta garden three years ago. Today, he's the citizen scientist who propagates native seeds. "My focus is getting to know each native plant intimately and learning which plant works best where," says Menning. "Aldo Leopold said that we can't really save anything unless we know about it, so I'm just trying to learn, and share what I know with others."

Ted Vorster, a landscape architect, also has a plot in the garden. He says he was happy puttering in his own backyard but became intrigued by an interpretive greenway exhibit Linn was spearheading in the neighborhood. The Ohlone Greenway is a bicycle and pedestrian path that passes directly in front of the Peralta and Northside gardens. The project will use a large kiosk made with volunteer labor to depict the history of the Ohlone people-the area's original residents-as well as the Mexican "Californios" who moved there in the 19th century. Biodiversity will also be on display along the path, as Menning, Vorster, and others continue planting native species. "This project is pushing against the whole direction of the landscape industry, which focuses on exotics rather than on plants appropriate to the ecological realities of a place," says Vorster. Linn agrees. "When I practiced landscape architecture in the fifties, those who were affluent liked to show off-the model of success being a huge lawn or a big tree that stood alone, looking like a king with a poochy belly, taking up all the nutrients in the soil." He adds that, thankfully, a growing ecological awareness has led to a focus on the profound relationships between things, "to the natural habitat and the healthy need for diversity."

Monika Bauerlein, a San Francisco resident who's writing a book about community gardens, is amazed by what Linn has achieved in Berkeley. "While community gardens are often insulated from the world around them-there are many with fences or signs discouraging casual visitors-Karl's are designed as public spaces from the start," says Bauerlein. The Berkeley gardens also have fences, but visiting hours are posted and the community is welcome. Linn does not apologize for the fences and locked gates, calling these protections a social-justice issue. "Private-property owners are privileged to have secure backyards," Linn argues. "Community gardeners who rely for sustenance on the food they grow should have the same security." What Linn describes as eco-justice-an idea that all people, regardless of race, creed, or class, should have access to nature's beauty, tillable land, and the fruits of their labor-remains a central theme in his life. That, and what Louis Kahn recognized nearly 40 years ago: the nurturance of human wonderfulness.