But Drexel University, which bought the 14-acre school site from the Philadelphia School District in June, plans to build a $1 billion complex of laboratories, offices, housing, and, possibly, a public school there.
Gardeners have been told to vacate the site by the end of the summer, and some trees on the perimeter have already been felled.
Lucy Kerman, Drexel's vice provost for university and community partnerships, said that the garden would not survive construction and that remediation would be necessary at the site.
She said Drexel offered to help find a replacement site, such as at the Mantua Urban Peace Garden at 37th and Brown Streets, about three-quarters of a mile away.
Donkey Dover, schoolyard garden manager for the nutrition initiative, a program of the University of Pennsylvania's Netter Center, said the farm's rich soil and mature trees could not be replaced easily.
He pointed out a 14-year-old plum tree, many students' favorite.
"That's the first place where they make that connection with growing food. The idea of pulling a carrot out of the ground, or a beet, it's not something that the youth might be used to," he said. "But the plums are irresistible."
That's not the only reason advocates want to stay put.
"This particular garden has this special situation where it really represents forced removal of a neighborhood by eminent domain," said Tony Larson, a former employee of the program.
The site was the heart of Black Bottom, which stretched from 32d Street west to 40th and from Lancaster and Powelton Avenues south to Sansom Street. The neighborhood was all but eradicated by 1970, through strategic purchases and condemnations.
Rowhouses at this particular site were razed to make way for University City High School, which was closed last year.
"The grandsons and granddaughters of the people who were kicked off this land cultivated this garden," Larson said. "It's like, here we go again."
Powelton Village Civic Association president John Phillips said the garden came up in community meetings about the development, but it was not the top priority. A number of community groups and interests had stakes in shaping the Drexel development, he said, and the gardeners "didn't squeak as loudly as some other people."
But he said community representatives value the garden and would advocate to preserve it in its current location or elsewhere.
The Urban Nutrition Initiative was created to improve food access and education in Philadelphia, but as students learned about the history of the garden site, they came up with the idea of adding a neighborhood memorial. They took oral histories from displaced residents and wrote text for panels hung in a gazebo they built themselves.
Former residents told them of an extraordinarily close-knit community where neighbors took care of one another like family.
When parents wanted to scare children straight, they would tell them to be home before dark, lest Penn medical students kidnap them for experiments, said Walter Palmer, a former resident. But, he said, their relationship with the university was symbiotic, since many residents worked there.
That changed in the 1960s, as rowhouse blocks were condemned to make way for the University City Science Center and the high school.
Palmer, 80, recalls cars burning in the streets, and racially charged protests over the removal of primarily African American residents. "I remember running barbed wire down 40th Street," he said.
The protests failed to exact many concessions, though two acres were carved out from the school complex, saving a handful of houses.
The farm, with its neighborhood history memorial, does not offer a happy ending to the story of Black Bottom, said Danny Gerber, who founded the nutrition initiative. But it does offer a quiet place to reflect and remember.
It also provides one or two tons of produce each year, to be donated or discounted for low-income residents or sold at Clark Park Farmers' Market. It also provides jobs and training to a dozen teens a year, inspiring many to follow careers in farming, cooking and food advocacy.
Because of uncertain access to the site this summer, though, Dover had to call off youth programming.
But he's been allowed to harvest the last of the garden's yield.