Can cities grow a lot more of their own food? Should they? The creators of the Gastropod podcast investigate.

BY CYNTHIA GRABER AND NICOLA TWILLEY

CRAIG F. WALKER/GLOBE STAFF

In March, as the United States began to lock down, shoppers met an unfamiliar and disturbing sight: empty shelves where bags of flour, jugs of milk, and packages of chicken breasts used to be. These shortages, combined with the “Groundhog Day”-like experience of being home day in, day out, for months on end, inspired a wave of gardening novices to try growing vegetables at home — and we at Gastropod, the podcast that looks at food through the lens of science and history, wanted to join in. To our dismay, we discovered that some of the plants we’d hoped to grow had long since sold out, like bags of flour before them, in what has been hailed as the great COVID-19 Victory Garden comeback.

This sudden, shared urge to grow food in the middle of America’s cities intrigued us — enough to make an episode on urban agriculture, featured above. As the creators of a food podcast, we’re well aware of the harms caused by the intensive, industrial system of agriculture that feeds America, from the food miles racked up by the average spinach leaf to the underpaid farmworkers who harvest it. Could the solution to these problems lie in diversifying where food is grown? Advocates claim that urban agriculture, which has been expanding in many ways in recent years, yields healthier diets, environmental benefits, and a host of more intangible outcomes, from beautification to food sovereignty. We couldn’t help but wonder: Might this spontaneous efflorescence of COVID Victory Gardens be part of a genuine shift, as America’s city-dwellers begin to feed themselves?

And, more importantly, is urban agriculture really the panacea our food system needs?

History provides some clues. The World War II Victory Gardens to which today’s COVID gardens have been compared were far from the first American urban garden movement. In the 1890s, faced with hunger and rioting following a stock market panic, Detroit’s mayor Hazen S. Pingree offered vacant lots to the city’s poor to grow food — a popular scheme that became known as the Potato Patch Plan. A few decades later, the Liberty Gardens effort of World War I urged newly urbanized Americans to grow vegetables to support the war.

But neither of these initiatives compared to Victory Gardens, the largest and most popular home gardening effort in the country’s history. Encouraged to pick up shovels and hoes by ubiquitous advertising campaigns, horticultural classes at city halls, and the patriotic urge to save commercial canned food for the troops, more than two-thirds of Americans planted seeds in windowsill pots, backyard patches, city parks, corporate factory campuses, and alongside railways.

The results were impressive: an estimated 43 percent of all the produce that Americans consumed in 1943 came from Victory Gardens. Not self-sufficiency, certainly, but enough to make a huge difference in the country’s food supply. Yet, as soon as the war ended, “whoosh!” said Anastasia Day, a historian of the movement. “They disappeared almost overnight.” Out of the hundreds of thousands of Victory Gardens that sprang up during the war years, only two remain, the oldest of which still occupies seven acres on Boston’s Fenway.

This makes more sense, Day told us, if you look at how those gardening efforts were framed. Contemporary discussions about urban farms position them as an alternative foodway, one that offers a stronger connection to nature, the possibility of regional self-sufficiency, and eco-friendly, organic produce. By contrast, Day told us that Victory Gardens were promoted as temporary replacement food factories for the war effort, in language that mimicked the country’s obsession with science and industry. And so, once the immediate need passed, home gardeners were happy to hand off the business of growing food to companies that could farm more efficiently. Many Victory Gardeners traded their urban veggie patches for the post-war era’s suburban lawns and white picket fences.

Urban gardening and farming largely fell out of favor over the next decades, and as it did, Americans missed out on its many benefits, said Leah Penniman, farm manager and co-director at Soul Fire Farm in Grafton, N.Y., and author of “Farming While Black.” Those benefits include, but extend well beyond, the joy of biting into a sun-warmed tomato. “It’s also the opportunity to get exercise, to be outside and feel connected to the earth, to have a meaningful activity, to engage with your loved ones,” she said.

Penniman told us that many African Americans who moved to northern cities during the Great Migration did try to grow food, and some succeeded, despite a lack of access to land and credit, as well as other obstacles created by systemic racism. Plenty of others, however, shied away from gardening. “For many people, there’s this visceral reaction to land, because land got mixed up with the oppression that took place on the land,” she said. “But to have a garden on your own terms, to grow food for your community that you find delicious — this is the process of healing from that trauma.”

According to Raychel Santo, a Johns Hopkins researcher and co-author of a recent analysis of urban agriculture, the evidence for such socio-cultural benefits from urban agriculture is overwhelming. Based on the more than 200 studies she reviewed, these benefits included getting to know neighbors, meeting people from different backgrounds, and being involved in something productive. “But they’re hard to quantify in numbers,” Santo told us.

The result is that, while anyone who has volunteered at a community garden or coaxed baby seedlings out of the ground understands the power of growing food, urban gardens are often seen as fuzzy, feel-good projects, rather than being taken seriously as an alternative mode of food production. Still, at least one health benefit can be quantified: Santo told us that studies have shown that city-dwellers who participate in some form of urban farming eat more vegetables. History offers support for this finding: During World War II, Americans consumed more produce then they have eaten before or since — at least in part because of the success of Victory Gardens. Given that only one in 10 Americans currently eats enough vegetables to meet federal regulations — and thus reduce their risk for many leading causes of illness and death, including heart disease and type 2 diabetes — the potential health benefits of expanding urban agriculture are significant.

Good for you, but good for the planet?

The environmental benefits of growing food in cities seem like they should be easier to pin down. Certainly, Santo said, like most urban green spaces, farms and vegetable gardens boost biodiversity, improve rainwater drainage, filter air pollution, and reduce the urban heat island effect. They also offer another tangible good, albeit one that can be challenging to implement: the opportunity to turn food scraps into compost and thus close the loop on some of the city’s waste.

Logic dictates that eating locally grown produce would also reduce emissions from food miles — but evidence for that has thus far been spotty. One widely cited analysis, published in 2008 by researchers at Carnegie Mellon, found that transportation accounted for only 11 percent of food’s carbon footprint. The authors used this finding to conclude that eating less meat and dairy was substantially more climate-friendly than eating local — but their analysis failed to take into account the greenhouse gas emissions associated with refrigerated warehouses and food spoilage. “There’s a lot of debate in this area,” Santo said. “I would say the literature is not very clear.”

Neil Mattson, professor of horticulture at Cornell University, is halfway through a three-year project that aims to tease out these nuances, at least when it comes to growing leafy greens in northern U.S. cities year-round versus shipping them from California. Lettuce is usually a seasonal harvest in community gardens, but, in recent years, there’s been increasing interest — and investment — in more high-tech urban farms. Some of these facilities are greenhouses, but others, often called “vertical farms,” resemble automated food factories, with rows of baby greens growing under glowing LEDs and in perfectly calibrated climactic conditions inside skyscrapers and tunnels from London to Tokyo.

This is where the promise of urban farming meets its most significant challenge: replicating the sun. When it comes to more traditional greenhouses, Mattson’s research shows that the energy needed to provide optimal heat and humidity levels is similar to the transportation energy of trucking lettuce across the country, making their carbon footprint at least comparable. (He is still working on a full life-cycle analysis that includes everything from the embodied cost of the glass and steel used in greenhouse construction to the emissions from transport refrigeration units.)

But those fully controlled vertical farms so beloved by techies, architects, and VC-funded entrepreneurs? Mattson has found providing sufficient electric light for photosynthesis and controlling the humidity sucks up twice the energy of growing lettuce in California and shipping it across the country. Until we get significantly more energy from renewable resources or invent dramatically more efficient lighting, even the most advanced vertical farms aren’t necessarily more sustainable than California’s Imperial Valley.

That said, both vertical farms and heated greenhouses do use significantly less water than California farms — 10 times less water, according to Mattson — and, as the West becomes more arid, water will likely become a limiting factor. In the future, Mattson says, climate-controlled urban farms of all sorts may well look like increasingly attractive options. They might be priced out of real estate in downtown Boston or New York, but traveling just an hour or two out of the city can connect growers to much cheaper places for indoor agriculture.

Mattson pointed out that our current food system is extremely centralized, meaning that the majority of produce is grown in a relatively small area. If drought, floods, or an E. coli outbreak hit, supermarket shelves are left empty across the nation. “Producing some proportion of our food in cities could make for a more robust system,” he said.

Self-sufficiency

Critics argue that we only get about 10 percent of our calories from vegetables and fruits, and so cities can neither feed themselves nor transform the country’s farming systems. Even the most passionate urban agriculture advocates, such as Keep Growing Detroit’s Tepfirah Rushdan, don’t imagine that cities will grow and process all their own grains. But could cities at least grow the vegetables they need? Here the data look promising. Rushdan told us that Keep Growing Detroit’s goal is food sovereignty, meaning that more than half the produce consumed in the city is grown there. Though that’s not yet reality — the organization says the results of their last produce weigh-in shows the city growing around 5 to 10 percent of what’s eaten — a Michigan State University study demonstrates that the city could theoretically supply nearly two-thirds of the demand. Similarly, researchers in New England have mapped out how the region could produce up to half of its vegetables in urban and suburban plots by 2060.

Kevin Washington, 14, waters plants at the Michigan Urban Farming Initiative in Detroit. The farm has taken over three acres of vacant lots and turned them into a green oasis of fruit trees, vegetables, and a sensory garden. Solely run by volunteers, the farm gives back all of the produce to the community for free.

Elsewhere, researchers have calculated that empty land in Cleveland could provide half the city’s fresh vegetables, and if commercial rooftops and a small amount of residential land were added, up to 100 percent — plus 94 percent of the city’s eggs and chickens. This spring, a study showed that Sheffield, England, has sufficient vacant land to grow enough fruits and vegetables to feed all its residents. Of course, urban farming will look different in different cities: In Boston, it might include city farms along the lines of the Fowler Clark Epstein Farm in Mattapan, as well as high-tech greenhouses on the outskirts of the city, such as Little Leaf Farms a half-hour away. There’ll be rooftop beehives, like those on top of the Lenox Hotel, and community plots in the South End. New York City’s expensive real estate might push much urban farming to the periphery; Detroit, where 17 percent of the city is considered vacant, is perfectly situated to expand internally.

Finally, though we agree with critics that putting your hands in the dirt won’t solve all the problems of the industrial agricultural system, we believe it could help, by connecting people to their food. “We do have to do both,” Rushdan told us. “We have to make time to focus on local production, and then we have to make time to address the larger systematic issues.”

The urban gardeners we spoke with hope that COVID-19 gardens won’t just be a temporary fad, but will, as Penniman put it, trigger “an awakening as to the type of structural changes that we need to make to have an equitable, just, and sustainable food system.”

After all, as Anastasia Day pointed out, World War II’s Victory Gardens may have vanished practically overnight, but the children who grew up tending them turned into adults who celebrated the first Earth Day in 1970.

Cynthia Graber and Nicola Twilley are journalists who host the Gastropod podcast, which explores the science and history of food.