Research Suggests Urban Farming Could Meet Almost 30% of Europe’s Fruit and Vegetable Demand

(SeaPRwire) –   Most urban rooftops are far from scenic—they’re either a tar-paper or concrete slab sweltering in summer heat, or a windswept, desolate patch in winter. But according to new research published in the journal Sustainable Cities and Society, city rooftops, alongside vacant lots and urban green spaces, could be transformed into something far different: working farms. When properly developed and repurposed, the study’s authors found, urban gardens could satisfy up to 28% of the fruit and vegetable requirements of 190 million people across Europe.

The study was led by Stepan Svintsov, a researcher at the Leibniz Institute of Ecological Urban and Regional Development in Dresden, Germany. The team used geographic information systems (GIS), a surveying and modeling tool, to catalog available rooftop and ground-level space across 840 cities in 30 European nations. The smallest city by population was Melun, France, with 9,000 residents, while the largest was Paris, home to 7 million people. By land area, the smallest city was Mislata, Spain, at 0.2 square kilometers, and the largest was once again Paris, spanning 100 square kilometers.

Not every potential urban plot mapped for agriculture will make a suitable growing site. The researchers do not plan to use high-tech growing systems like vertical farms or hydroponics. Instead, their focus is on the most accessible option for most people: traditional, low-tech, soil-based farming. This creates a low barrier to entry, but also brings with it the same challenges that must be managed on traditional farms—including soil erosion and nutrient runoff. For this reason, they only selected rooftops with a slope of no more than 2°.

“We need to level the rooftop,” explains Prajal Pradhan, an associate professor in the faculty of science and engineering at the University of Groningen in the Netherlands and a co-author of the study. “That’s how we arrived at the two-degree rule.”

Europe’s regions also vary widely in their suitability for urban farming. Southern Europe faces water shortages and high evaporation rates that restrict urban agricultural efforts. Northern Europe has shorter growing seasons due to lower temperatures and less daylight. Central and Western Europe face local constraints including high population density and competing land uses.

After accounting for all these variables, the researchers determined that between 4,500 and 7,500 square kilometers of urban land and rooftops could be used for farming—an area equal to up to two islands the size of Mallorca. On average, up to 9% of a city’s total land area could support rooftop farming, while 7.2% could be used for ground-level cultivation.

This adds up to a massive supply of fruits and vegetables—between 11.8 million and 19.8 million tons each year. Different cities will see varying benefits from this local produce. For example, Berlin could meet up to 45% of its own produce needs by growing food within city limits. Cerdanyola del Vallè, a town near Barcelona, would actually have a harvest surplus, producing enough food to cover 140% of its annual needs. When scaled up beyond Europe to the global stage, the researchers reference another study that found urban farming could meet 5% to 10% of the world’s fruit and vegetable requirements.

Urban farming does more than stock grocery store shelves and farmers’ markets—it also cuts greenhouse gas emissions by eliminating the carbon footprint created by shipping fruits and vegetables across continents or oceans. “Take a tomato grown in Spain and shipped to Germany,” Pradhan says. “Compare that to a tomato grown right in Berlin.”

The so-called “last mile problem”—the distance consumers travel from their homes to grocery stores to purchase produce—could also be eliminated or drastically reduced. When crops are grown directly on nearby rooftops or adjacent lots, no travel is needed at all. All of this works toward achieving the 15-minute city ideal: designing urban spaces so that residents are no more than a one-km, 15-minute walk or bicycle trip from all of their basic needs.

Urban farming also offers other secondary benefits, most notably reducing urban temperatures. In summer, brick, concrete, and asphalt cities act as nothing short of heat traps, baking in intense sunlight during the day and radiating heat back out at night. Covering rooftops and empty lots with vegetation counteracts this effect, creating an overall cooling impact. Pradhan cites studies showing that residences near an urban garden experience lower summertime temperatures than those located farther away.

Transforming underused urban space into farmland is not a perfect solution. The researchers concede that growing crops within urban centers could expose food to heavy metals like lead, zinc, cadmium, and nickel, carried in runoff from cars, factories, and aging buildings. What’s more, every hectare (2.5 acres) of urban land converted to farming is one less hectare of greenspace available for recreation—a critical feature for any livable city.

Even so, the researchers conclude that the benefits—both literal and metaphorical—of urban farming easily outweigh the downsides, contributing not only to better provisioned residents but also happier, healthier communities.

“There are a great many benefits tied to mental health,” Pradhan says. “It’s not only about biodiversity, not only about the environment, not only about food access—it’s also about embracing a healthy way of living. All of these elements are part of a holistic, healthy lifestyle.”