Beckman said the test results weren't a surprise. His neighborhood is mostly made up of homes built in the 1940s, when lead paint was in wide use.
"I probably should have been more aware of it at the time, but it (the TV show) was one of those 'ah-ha moments,'" Beckman said.
Filippelli, an earth sciences professor at Indiana University-Purdue University Indianapolis, said Beckman's test results were typical of what he sees around the city: Lead levels were higher in soil near the street, where cars burning leaded gasoline once drove, and near the area where water runs off the house, known as the drip line. Based on tests at about 60 gardens around the city, Filippelli said about 90 percent need some kind of work to make gardening safe.
Beckman said the tests made him think about steps, such as putting down mulch near the house, to keep dust from lead-tainted areas from blowing into his garden beds. With the planting season approaching, other alternatives for gardeners include trucking in clean soil that can be placed on top of potentially contaminated land to create raised beds and moving their plants away from contaminated areas.
While no one knows exactly how many urban residents are growing food, the U.S. Department of Agriculture estimates there are thousands of community gardens nationwide. The American Community Gardening Association said it has more than 2,600 active listings in its online database and has seen a steady increase in people inquiring about community gardening in recent years.
In the Boston suburbs of Roxbury and Dorchester, where four out of five backyard gardens tested had high lead levels, new research has suggested that a one-time fix isn't enough to keep soil safe. The nonprofit Food Project installed raised beds filled with freshly composted soil, but tests showed the lead content in some tripled in just four years. Researchers say that while more study is needed, the early results suggest growers need to change the way they think about city soil and test not only when they first plant but as years go by.