Our best estimates of the scale of urban agriculture typically come from self-reported lists and non-profit groups trying to keep tabs on shared community gardens. These lists are, like the gardens themselves, informal. One frequent estimate floating around Chicago for several years figured there were maybe 700 food-producing plots in the city.
But when researchers from the University of Illinois tried to visit some of them, they more often found planter boxes or ornamental gardens, nothing that could truly be considered part of the city’s food supply. It then occurred to John Taylor, a doctoral candidate in crop sciences at the university, that Google Earth images might reveal what ground-level surveys of the city had not: the true extent of its urban agriculture.
Taylor spent some 400 hours twice poring over aerial images of every corner of the city. "And lo and behold," he says, "it’s possible to tell whether or not the gardens had vegetables based on these visual indicators."
A vegetable plot in fact has a distinct fingerprint – apart from neighborhood parks and plain old backyards – that’s visible even from thousands of feet overhead. Witness the telltale linear geometry of these sizable gardens on vacant lots in what appear to be railroad rights-of-way on either side of these tracks:
Taylor and collaborator Sarah Lovell, who’ve published their findings in the journal Landscape and Urban Planning, ultimately discovered that many of the city’s suspected community gardens weren’t producing food at all. But it turned out that backyard farmers all over Chicago – the keepers of "invisible" gardens no one sees from the sidewalk – may be seriously supplementing communities’ food supply in a way that researchers and advocates haven’t recognized before.
Of the 1,236 documented "community gardens," recognized by various groups throughout the city, it turned out only 160 – or 13 percent – were really growing food (according to aerial images from June of 2010). But trolling over the city, frame by frame on Google Earth, Taylor found what looked like 4,494 possible sites of urban agriculture, many of which appeared to be small residential gardens. Their total mass adds up to 264,181 square meters of urban agriculture, much of it on the city’s South and West sides and far northwest where minority and immigrant communities are located.
"There is often this idea that urban agriculture is something that’s new and sometimes perceived to be trendy," Taylor says. "But of course it’s just been going on for generations in people’s backyards and in these interstitial spaces, like right-of-ways and vacant lots. Across the city, there are lots of folks who are doing this on their own, or with support from their neighbors."
One garden in the city’s South Shore neighborhood has even been continuously cultivated since it was first planted as a victory garden during World War II. In other neighborhoods, particularly around Chinatown and in Eastern and Southern European communities of the northwest side, nearly every backyard viewed through Google Earth appears to be growing something.
These types of backyard growers seldom figure into public discussion and policy debates about urban agriculture. We more often focus on community gardens. But these images suggest we might think instead about urban agriculture, food deserts and neighborhood sustainability with an eye toward a network of smaller growers rather than a few epicenters.
Taylor followed up on his aerial tours with some “groundtruthing,” by visiting some of these neighborhoods and peering through alleys to ensure that he saw on the ground what Google Earth seemed to be suggesting from above. Some images from his verification:
Automated technology hasn’t yet reached the point where a computer program can find vegetable patterns in aerial imagery so that a human researcher doesn’t have to. But for now, Taylor’s technique is replicable in other cities, if anyone has the patience.
"Community groups could use it," Taylor says. "And there also may be opportunities for crowdsourcing of this kind, using social media to get multiple people involved so that it’s not just one lone graduate student sitting in a darkened room for 400 hours."
All images courtesy of John Taylor.