Urban gardeners don’t like to talk about contaminated soil. After all, who wants to dwell on the chemical legacy of industry, illegal dumping, paint chips, and leaded gasoline when you can discuss bees, the weather, or the cool purple beans you’re growing?
But city growers must tackle this elephant-in-the-room subject. That’s the message Brent Kim, a program officer at the Bloomberg School of Public Health at Johns Hopkins University, wants you to know.
A community gardener himself, Kim works closely with Baltimore’s urban farmers and gardeners. A few years ago, he began to wonder about the “known unknowns” of urban ag. What, if anything, did Baltimore’s farmers and gardeners know about the risks associated with soil that might contain lead, arsenic, petrochemicals, cleaning solvents or worse?
So Kim and five colleagues surveyed 70 gardeners in 15 of Baltimore’s community gardens. As an older, East Coast city with an industrial past, Baltimore has a panoply of potential soil issues that complicate life for anyone growing their own food. In other words, it’s fertile ground to gauge how worried people are—or aren’t—about contaminants.
In a paper that appeared in the journal PLOS One this February, Kim and his team laid out their findings. Almost half the gardeners (30 out of 70) had farmed their soil without testing it. Among those whose soil had been tested, there was a general sense that the soil had remained the same since the test.
Oddly, even when gardeners tested their soil and found contamination, they didn’t seem particularly worried. In the words of the study’s authors: “There was no apparent association between levels of concern and whether gardeners thought their soil had been tested, or what they thought the test results indicated.”
“Many leaders in the gardening community are saying, ‘Just use a raised bed and you’re good to go,’” Kim said.
It seems that these two useful techniques—soil sampling and raised beds—have given urban growers a false sense of security. But both have significant limitations that more gardeners need to understand.
For one, many tests commonly available at a reasonable price, “don’t really test for the spectrum of possible contaminants,” Kim explained. “It will test for lead and maybe cadmium or arsenic, but it’s not going to paint the full picture.”