Karl was born March 11, 1923, and grew up on a fruit tree farm in the small village of Dessow in der Mark, about 60 miles north of Berlin. Karl's mother, Henrietta (Henny) Rosenthal had founded the Immenhof (literally "beekeepers farm") in 1910. Her cherries, plums, and berries were eagerly awaited in the marketplaces in Berlin. The farm was also an accredited training center for gardeners and one of the first sites to practice horticultural therapy. In 1921 Henny married Josef Lin, a widower with three children, whom she adopted. Josef was Chief Librarian of the Jewish Community Center in Berlin. He edited Hakeshet, a journal of Jewish poets and writers, and published a book on the evolution of the Hebrew press.
As the only Jews in Dessow, Karl's family faced Nazi persecution. They were forced to flee to Palestine in 1934 and started a small farm near Haifa. At age 14 Karl left school to farm to support his parents, who had become too sick to work. Later he graduated from the Kadoorie School of Agriculture and joined with other youth to found a kibbutz. At age 20 he moved to Tel Aviv where he developed an elementary school gardening program that engaged students in growing food for their own lunches.
At age 23, he moved to Switzerland and was trained as a psychoanalyst at the Institute for Applied Psychology in Zurich. He later immigrated to New York, where he cofounded a school for emotionally disturbed children and conducted a private practice as a child psychoanalyst.
Karl returned to landscape architecture in 1952 eager to contribute to building a healthy society by shaping open spaces. He pursued a distinguished private practice in landscape architecture during the 1950s. He was landscape architect for the Seagram Building in New York and designed the indoor landscape for the building's Four Seasons Restaurant. Gradually he experienced the wealthy suburbs as "green deserts," devoid of public playgrounds, sidewalks, and benches where people could sit and talk.
In 1959, he accepted an invitation by Ian McHarg to join the Landscape Architecture faculty at the University of Pennsylvania. Linn took his students into economically disenfranchised communities in the inner city, to provide planning and design service to neighborhood residents, building combination park-playgrounds Linn called neighborhood commons. Linn also engaged volunteer professionals, youth teams, social service agencies, and city governments in constructing the commons.
During the early 1960s Linn founded and directed pioneering community design-and-build centers in Philadelphia and Washington, DC, which became models for the Domestic Peace Corps. Subsequently he inspired the creation of similar centers in eight other cities.
He also guided students and audiences in creating instant commons in lecture halls on college campuses. He served as a ceremonialist for a number of conferences and events, transforming hotel ballrooms and other institutional settings into vibrant temporary commons.
He taught for four years at Massachusetts Institute of Technology (MIT) in Boston, for nine years at New Jersey Institute of Technology (NJIT), and shorter terms at a number of other colleges. He gave numerous lectures and workshops and received many honors and awards.
When the nuclear arms race heated up in the early 1980s, Linn began to conduct workshops to help students break through fears and anxiety about the future that hampered their ability to design spaces. He worked with Interhelp, an international organization of psychotherapists, who used exercises developed by Buddhist scholar Joanna Macy to help participants release their suppressed feelings about the possibility of nuclear destruction. By sharing their grief with others they renewed their commitment to work to preserve life.
Retiring early from his tenured position at the New Jersey Institute of Technology in 1986, Linn worked full-time for nuclear disarmament as a founding member of the national organization of Architects, Designers and Planners for Social Responsibility (ADPSR). Chairing its committee on education, he worked with students to organize conferences and workshops on the creation of peace gardens and peace parks, and other places for peacemaking.
Linn moved to the San Francisco Bay Area in the late 1980s. After volunteering for a year at Earth Island Institute (EII), he teamed up with his old friend African-American architect Carl Anthony to start the Urban Habitat Program, with support from EII founder David Brower.
Linn served on the Board of San Francisco League of Urban Gardeners for seven years and helped found East Bay Urban Gardeners and the People of Color Greening Network. He held key positions in Berkeley Partners for Parks and Berkeley Design Advocates and served on the steering committee of Berkeley's Community Gardening Collaborative after cofounding it in 1995.
In 1993 a small community garden in the Westbrae neighborhood was dedicated as the Karl Linn Community Garden at a surprise 70th birthday to honor his lifelong service to community and peace. Linn soon began collaborating with neighbor and UCB landscape architecture professor Linda Jewell, whose class worked with gardeners, neighbors, and a team of volunteer professionals to refurbish the garden and construct a handcrafted commons.
As the waiting list for garden plots grew longer, Linn spotted unused land across the street, owned by Bay Area Rapid Transit (BART), the regional light rail system. With support from Berkeley City Councilwoman Linda Maio, Linn guided the development of the Peralta and Northside Community Art Gardens, Westbrae Commons where ecological innovations and works of art intermingle with lush vegetation. The circular commons of the Peralta Garden, surrounded by a mosaic Snake Bench and colorful native California plants, is widely used for meetings and workshops by neighbors and local organizations.
In 1999, Linn collaborated with community and environmental activists, city officials and other supporters to establish Berkeley EcoHouse -- acquiring a small house that had come up for sale right next to the Karl Linn Community Garden. EcoHouse is a model of ecological construction and renovation and houses a solar energy education project that serves Berkeley schools.
Later that year, as part of the American Society of Landscape Architects' Centennial Celebration, Linn conceptualized the creation of an interpretive exhibit of the natural and cultural history of the Westbrae neighborhood in a section of the Ohlone Greenway adjacent to the Peralta Garden. He coordinated several phases of its implementation, culminating in an exhibit to honor the original inhabitants of the area, the Ohlone peoples. A coastal prairie habitat is being restored alongside the Greenway path by members of California Habitat Indigenous Activists (CHIA), a group founded by Peralta gardeners.
Video documentarian Rick Bacigalupi worked for several years with Linn and the Peralta gardeners to create "A Lot in Common," an hour-long feature about how the garden grows community along with produce. Distributed to public television stations by National Educational Television Association (NETA) and to educational and home viewers by Bullfrog Films, the film has been aired on PBS stations nationwide.
The concept of commons relates not only to land; it also relates to the airwaves. Through his wife Nicole Milner, Karl became deeply concerned about the years-long struggle to preserve the tradition of the Pacifica network of radio stations -- of which KPFA Berkeley is the oldest -- as outlets for free and unfettered reporting closely connected to the communities they serve.
Karl was also active in establishing Arab-Jewish dialogue in the Bay Area. Over three years ago, he cofounded the East Bay Dialogue Group, a group of 40 Jews and Arabs who continue to meet monthly.
The College of Environmental Design at UC Berkeley now houses Karl's archives.
The Regional Oral History Office (ROHO) at UC Berkeley's Bancroft Library conducted a series of interviews about his life and work.