A new life for empty offices: Growing kale and cucumbers
In some cities, as many as one in four office spaces are vacant. Some start-ups are giving them a second life – as indoor farms growing crops as varied as kale, cucumber and herbs.
Since its 1967 construction, Canada's "Calgary Tower", a 190m (623ft) concrete-and-steel observation tower in Calgary, Alberta, has been home to an observation deck, panoramic restaurants and souvenir shops. Last year, it welcomed a different kind of business: a fully functioning indoor farm.
Sprawling across 6,000sq m (65,000 sq ft), the farm, which produces dozens of crops including strawberries, kale and cucumber, is a striking example of the search for city-grown food. But it's hardly alone. From Japan to Singapore to Dubai, vertical indoor farms – where crops can be grown in climate-controlled environments with hydroponics, aquaponics or aeroponics techniques – have been popping up around the world.
While indoor farming had been on the rise for years, a watershed moment came during the Covid-19 pandemic, when disruptions to the food supply chain underscored the need for local solutions. In 2021, $6bn (£4.8bn) in vertical farming deals were registered globally – the peak year for vertical farming investment. As the global economy entered its post-pandemic phase, some high-profile startups like Fifth Season went out of business, and others including Planted Detroit and AeroFarms running into a period of financial difficulty. Some commentators questioned whether a "vertical farming bubble" had popped.
But a new, post-pandemic trend may give the sector a boost. In countries including Canada and Australia, landlords are struggling to fill vacant office spaces as companies embrace remote and hybrid work. In the US, the office vacancy rate is more than 20%.
"Vertical farms may prove to be a cost-effective way to fill in vacant office buildings," says Warren Seay, Jr, a real estate finance partner in the Washington DC offices of US law firm ArentFox Schiff, who authored an article on urban farm reconversions.
There are other reasons for the interest in urban farms, too. Though supply chains have largely recovered post-Covid-19, other global shocks, including climate change, geopolitical turmoil and farmers' strikes, mean that they continue to be vulnerable – driving more cities to look for local food production options.
Office-to-farm conversions have made headlines in recent months. Workers are currently aiming to transform a floor of 32-story historic Niels Esperson building in Houston, Texas, into an indoor farm. In September 2024, US indoor farm startup 80 Acres, which opened its first indoor farm inside a vacant building in Hamilton, Ohio, developed a 200,000-sq-ft (18,600-sq-m) facility inside a former commercial building in Florence, Kentucky.
One obvious use of vacant office space is to convert it to residential housing. But a vertical farm conversion is, perhaps surprisingly, often easier. "When converting an office space into apartments, you need to carve out individual units, each needing access to natural light and plumbing," Seay says. "That's not an easy task in a building designed for cubicles and conference rooms."
On the other hand, the open-plan nature of most modern offices, or warehouses, can be more amenable to indoor farm use. Still, retrofitting, particularly to ensure a space can fit the proper equipment as well as have appropriate electrical, heating, ventilation and air conditioning (HVC) systems, can be difficult.
The Calgary Tower project, developed by the company Agriplay Ventures, has worked to overcome these hurdles. Agriplay uses silo technology, made of 1-by-2.5m (4-by-8ft) wide racks rising up to 3m (10ft) tall, that can easily adapt to any space with ventilation. The modular racks are also easy to remove once a project is done, leaving landlords with the option of converting the premises for different uses, says Agriplay's chief executive Adam Morand.
Thanks to artificial light and controlled temperatures, offices are proving surprisingly good environments for indoor agriculture, spurring some companies to convert part of their facilities into small farms. Since 2022, Australia's start-up Greenspace has worked with clients like Deloitte and Commonwealth Bank to turn "dead zones", like the space between lifts and meeting rooms, into 2m (6ft) tall hydroponic cabinets growing leafy greens.
On top of being adaptable to indoor farm operations, vacant office buildings offer the advantage of proximity to final consumers.
In a former paper storage warehouse in Arlington, about a mile outside of Washington DC, Jacqueline Potter and the team at Area 2 Farms are growing over 180 organic varieties of lettuce, greens, root vegetables, herbs and micro-greens. By serving consumers 10 miles away or less, the company has driven down transport costs and associated greenhouse emissions.
This also frees the team up to grow other types of food that can be hard to find elsewhere – such as edible flower species like buzz buttons and nasturtium. "Most crops are now selected to be grown because of their ability to withstand a 1,500-mile journey," Potter says, referring to the average distance covered by crops in the US before reaching customers. "In our farm, we can select crops for other properties like their nutritional value or taste."
Overall, vertical farms have the potential to outperform regular farms on several environmental sustainability metrics like water usage, says Evan Fraser, professor of geography at the University of Guelph in Ontario, Canada and the director of the Arell Food Institute, a research centre on sustainable food production. Most indoor farms report using a tiny fraction of the water that outdoor farms use. Indoor farms also report greater output per square mile than regular farms.
Energy use, however, is the "Achilles heel" of this sector, says Fraser: vertical farms need a lot of electricity to run lighting and ventilation systems, smart sensors and automated harvesting technologies. But if energy is sourced from renewable sources, they can outperform regular farms on this metric too, he says.
Because of variations in operational setup, it is hard to make a general assessment of the environmental, social and economic sustainability of indoor farms, says Jiangxiao Qiu, a landscape ecologist at the University of Florida and author of a study on urban agriculture's role in sustainability. Still, he agrees with Fraser: in general, urban indoor farms have higher crop yield per square foot, greater water and nutrient-use efficiency, better resistance to pests and shorter distance to market. Downsides include high energy use due to lighting, ventilation and air conditioning.
They face other challenges, too. As Seay notes, zoning laws often do not allow for agricultural activity within urban areas (although some cities like Arlington, Virginia, and Cincinnati, Ohio, have recently updated zoning to allow indoor farms). This means it is hard for them to produce staple crops like wheat, corn or rice indoors. However, these crops are rarely the focus for indoor farms, as crop range is also a limitation, says Fraser. Aside from leafy greens, most indoor facilities cannot yet produce other types of crops at scale.
But as long as the post-pandemic trends of remote work and corporate downsizing will last, indoor farms may keep popping up in cities around the world, Seay says.
"One thing cities dislike more than anything is unused spaces that don't drive economic growth," he says. "If indoor farm conversions in cities like Arlington prove successful, others may follow suit."
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