The people building edible cities 541e42

But what "new" spaces can cities offer? Some urban farms, like Peas&Love, use unexpected sites in cities to create "third places" where people can reconnect with nature and their alimentation. Office building roofs, railway tracks and even underused parking lots can now host urban farms.

While large areas of flat roofs provide suitable growing spaces in some cities – particularly in the US, and parts of Europe rebuilt after World War Two – for a city like Paris and other historic centres, the majority of roofs are not flat and buildings might be protected by law. 

Three young architects from MIT co-founded Roofscapes, a start-up company to "tackle the untapped spaces in Paris". Their idea takes after Venetian terraces – known as altane – and aims to green the sloping Parisian roofs without damaging them. Many Haussmanian zinc roofs are classified as national patrimony in the French capital – a status that prevents them from being modified. But, as the horizontal space available in cities decreases, verticality gains interest in urban design. 

Eytan Levi, one of the three Roofscapes entrepreneurs, explains that their project started as a student challenge and their interest grew as they explored the value of adding green space in a dense city. At the 2021 Seoul Biennale of Design, they displayed a model sharing their vision for alternative walkways above the city, on which gardening plots line paths. Their belief, which they share with other open-air urban farmers, is that urban agriculture should contribute to increasing urban biodiversity, such as by providing a source of food for insects.

Beekeeping in cities is growing in popularity – the 50% rise in beekeepers in Berlin between 2006 and 2012 is one example among many. But hives can only function if there are also more plants for bees to collect nectar from, especially as the urban beekeeping trend seems to create competition with wild native species. Therefore, the keepers need to ensure a balance between their honeybees, other insects and the flora available.

If we need to increase flora to provide food for insect species amid global declines in their numbers – might it be sensible to make those plants edible? That's one of the founding principles of permaculture. For example, in the British town of Todmorden, the network "Incredible Edible", started by Pam Warhurst and Mary Clear, grows edibles in public spaces to increase biodiversity and access to food.

Other than biodiversity, do city farms have any other positive environmental impacts? At the cutting edge of urban farming are cities like Tokyo, Singapore and Hong Kong. Cultivating in these cities is not new, especially in Japan. The metropolis of Tokyo has been questioning its need to import 80% of its food. Some high-end restaurant chefs interested in sustainability have turned to hydroponic and aeroponic urban farms for locally grown products. 

As a result, Japanese urban farmers are encouraged to grow high value products, especially micro herbs and greens, and exotic plants that could not be grown locally otherwise. At the moment, the scarcity of urban farm spaces and a narrow range of technical solutions encourages a niche type of agriculture. 

While indoor urban farms like those in Tokyo allow growers to reduce air miles and food waste, unlike Incredible Edible and the other movements to introduce flora to cities, they have little impact on urban biodiversity. Open-air urban farmers also acknowledge the efficiency of their indoor counterparts but claim their own methods are more sustainable, as indoor farms rely on electricity to power lighting and provide heat – which an outdoor farm can obtain from the Sun. 

But, defendants of indoor farms argue their farms use up to 90% less water. Indoor vertical farms can be a precious solution for areas with a lack of agricultural land such as Singapore, which is a leader in this industry. It is also a valuable tool in places with climate conditions unfavourable to outdoor cultivation, like Nordic countries for instance.

Both indoor and traditional farms are also turning to automation to harvest their crops in an efficient way. But there is still much that needs perfecting. Robots find it harder to pluck fresh produce without damaging it, for example. In the video below, James Wong looks at suction-powered strawberry pickers that can pick fruit without leaving a mark.

With the technology available to farm in cities, an increasing appetite for local produce and enterprising farmers finding spaces in unusual places, you might wonder if the future farm will be entirely urban. But does total urban farming really make sense?

"I really question what we are doing," says Yohan Hubert, founder of urban farm Sous les Fraises and pioneer of urban farms in . With his successful enterprise (30 sites across major French cities, mostly opened in the past six years), this remark sounds surprising. 

However, the entrepreneur points out that urban farms face many barriers. Roofscapes, for example, had complexities in getting legal authorisations to install a pilot terrace. Urban farms are also not well suited to producing some crops like grains, which require large surface areas to grow at scale. It may never be possible to grow wheat for flour in a city, yet cereals and grains make up the vast majority of the calories the world consumes.

"Your farm may be kicked out of a roof almost overnight, and people expect you to pay high rents when your activity already makes little profit in rural areas," adds Hubert. "If you want to have employees, let alone pay them decently, you are on a mission." All these constraints illustrate the challenges of this activity, popular on the surface, but difficult to make a living from. Newcomers want to be competitive, and abide by market forces, but their chances of being profitable are slim at present. 

Levi, Hubert and Brassier all agree on the necessity of a good economic model and that many hurdles remain for the urban farmer. It is not easier to grow in an urban environment, and a clear vision of the goals is needed, they say. 

Questions still remain for these farmers: should urban producers align their prices to each other? Should there be regulations on the use of urban space for activities that benefit urban biodiversity" says Hubert.

Given the constraints of urban farming, it is unlikely to ever replace rural agriculture as the main source of food, especially in countries with favourable growing conditions. But it may offer new local growing options and shorter supply chains in certain areas, while also enriching urban biodiversity and creating new bonds between urban and rural environments. Hubert and Brassier's work has made them reflect deeply on the experience of life in the city and in the countryside, leaving them keen to find solutions to improve quality of life in each. 

"Our aim is to reconnect people and the city to the land," Brassier says about their effort to create growing spaces in the centres of Brussels and Paris. Even if only half of their sites are profitable to this day, he remains hopeful about his mission based on the change he has seen in his subscribers week after week. 

"I enrol people in February and if they make it through the toughest part of the year, I know they will stick with us for the nicer months," he adds with a smile. And if they do, they might also have the chance to enjoy a fresh strawberry plucked from a kitchen garden high above the hustle and bustle of the city.

*Axelle Parriaux is an agricultural engineer and urban designer who holds a master's degree in urban design and city planning from The Bartlett School of Planning, University College London