Imagine a glass-walled skyscraper in the midst of a bustling American metropolis. Instead of offices and cubicles, though, this high-rise is filled with rows and rows of tomatoes, lettuce, squash and cucumbers. The elevator takes you past whole floors of strawberries, broccoli, and corn plants – all thriving hundreds of feet above the city streets. High above the honking taxis and pedestrians you may even find indoor fish-farms and chicken coops.
Welcome to the Vertical Farm.
With sustainable buildings and "cradle-to-cradle" design already the hottest thing in architecture, Columbia professor Dickson Despommier has an idea for a truly "green" building that is far grander. Leveraging new energy-efficient technologies and "closed loop" systems that reduce or eliminate waste, Despommier and his students have conceived a towering greenhouse-in-the-sky that could produce enough food to feed 60,000 people — winter, summer, spring and fall.
Unlike traditional farms which consume vast amounts of water and spew torrents of toxic run-off, this farm would use a living machine of microbes and algae to treat sewage. The treated water would then be pumped back through 30 stories of organic crops, grown with ultra-efficient aeroponics and 24 hour lighting systems. The building would compost organic waste in a bio-gas reactor, and capture evaporated moisture from the ceilings of the humid grow rooms.
The result? Ripe produce, renewable energy, and fresh water – right in the cities where they’re needed most.
While this may sound too good to be true, Despommier and his students insist that, while still theoretical, their dream can be realized using currently available technologies. What's more, to hear them tell it, transforming this surreal vision into living, breathing reality is vitally important — in fact, they say, the future of farming may depend on it.
Old problem, new approach
Cultivating crops has been the defining act of civilization since the first wheat fields sprang up in the Mesopotamia’s Fertile Crescent. In the ensuing millenia, agriculture has allowed humanity to vastly increase its numbers and spread across the globe - but has wreaked havoc on the environment in the process.
Deforestation and depletion of topsoil have been going on for centuries, while the advent of mechanized, mono-crop farming has led to the use of an increasingly toxic batch of chemical pesticides. As unwanted species adapt to these poisons, farmers must use increasingly potent doses which flood into the ecosystem after every rainfall, and contaminate groundwater year after year. “This is why the single most damaging source of pollution is agricultural runoff,” notes Despommier.
But letting machines and chemicals do the farming has freed us up for other things – among them, urbanization. And lets face it, we’re not going to move out of the city and back to the farm; in fact, the trend is just the opposite. In 1800, nearly 90 percent of the labor force in America was working on farms. That number had fallen to 40 percent by 1900, and is below four percent today. This year, for the first time in history, more than half of humanity will live in urban areas. And by 2050, forecasters say, nearly 80 percent of our species will be city dwellers.
Meanwhile, Despommier points out, we’ve used up virtually all the world’s arable land - and with three billion more humans headed for our crowded planet in the next few decades, we’re flat out of room. After attending a meeting of agricultural experts in August, he says, “I was stunned that they recognize across the board that in 25 years there won’t be farming as we know it in California.”
We are effectively sowing our fields with chemical salts; and large agricultural suppliers like Delmonte, Hunt and Dole are already outsourcing asparagus, spinach, and tomatoes to China, India, and Mexico. The World Bank, which ensures agricultural loans, reports that soil is being used up at a rate twenty times greater than it’s being replaced. And this year, the ‘breadbasket of the world’ is set to become a net food importer for the first time in our history.
Faced with these facts, Despommier argues, why not bring farming back to the people? Urban planners, at long last, have begun to recognize that sprawl is an incredibly inefficient way for people to live. Vertical Farming simply applies that same logic to our crops.
An idea that grew on its own
You might expect the creator of such a bold idea would be an environmental land planner, a sustainable architect, or a visionary horticulturalist. Actually, it was another concern entirely that led Despommier to his agricultural brainstorm. As a professor of microbiology at Columbia University’s Mailman School of Public Health in New York City, Despommier is intimately familiar with the diseases humanity encounters at the agricultural interface, and is an expert in the spread of infectious microbes such as the West Nile virus. From “bird flu” to the recent spinach scare, many potent diseases are encountered and spread through unsafe farming practices, through agriculture’s penetration into new ecological zones, and in the modern pollutants used to combat these diseases.
In 2001, while teaching a class in medical ecology, Dr. Despommier challenged his students to come up with an agricultural method that would reduce the risk of infectious diseases. They quickly realized that growing crops indoors had many advantages. By eliminating contact with the external environment, you avoid the need for pesticides, so you can grow crops organically. In addition, using artificial light and heat means the plants are never subject to frost or flood, and you can grow crops 24 hours a day, year round.
Of course, all of this is also true of greenhouses, a domain where technology and production capacities have expanded rapidly over the last decade. Fittingly, though, it was New Yorkers who first thought of turning a skyscraper into a farm. Initially, Despommier told ArcWire, “I speculated that abandoned apartment housing in NYC might be available and green house technologies applied to them.” The idea, he says, “has obviously ‘grown’ on its own since that moment in class when I suggested it.”
The Vertical Farm Project
Each year, Despommier’s students form teams to look at cash crop viability, new building materials, efficient energy systems, and marketing strategies. The Vertical Farm Project is thus an ongoing experiment. As each class analyzes and improves upon the work of its predecessors, they advance the model and incorporate the latest developments from a wide-range of disciplines.
The students have followed the work of a Cornell facility that can grow 470 tons of lettuce per acre versus 20 tons per acre using traditional methods – and consumes just 2 gallons of water per pound of lettuce using a hydroponic system, rather than the 70 gallons that “modern” agriculture requires. They note that a strawberry farmer in New Orleans moved his crop indoors after Hurricane Katrina, and now grows on one acre what it took 30 acres of land to grow before. Having studied the market, they calculate that New Yorkers spend $100 million dollars a year on lettuce alone - and conclude that a well run Vertical Farm could earn a million dollars a month.
But the radical gains in efficiency that could make vertical farming a profitable model are only part of the story. Food-safety has also become a major concern. With dozens of ingredients from all over the globe going into the average grocery store product, it is very difficult to know who produces our food. By contrast, imagine a Whole Foods that grew all its groceries organically in a glass tower right above the store: no more searching spinach farms across the country to find out who didn’t wash their hands.
Add to this the fact that transportation represents up to two-thirds of the cost of some produce, and you’ve saved a pile of money by growing food in the same cities where it’s consumed. Consider, too, that since there’s no need to harvest crops months in advance, they can ripen on the vine, providing tastier, more nutritious fruits and vegetables. Protected from the weather – and from climate change - crops won’t freeze, flood, or spoil on the way to market, so consumers end up with a cheaper, more dependable product.
“The NY city farm footprint is the size of Virginia. That’s how much land we could save by feeding 7.5 million people in the city,” says Despommier. He adds that even though real-estate costs in New York are among the highest in the country, “On Governors Island, the South Bronx, and in Harlem, there are still nearly 6,000 acres of land that nobody can find a use for.” These industrial brownfields, vacant lots, or otherwise unusable spaces could be devoted to vertical farming. A city block is five square acres; and with 170 buildings that size, Despommier could feed the entire city on a fraction of the land that nobody else wants.
So why hasn’t this been done before? “It’s because of the engineering integration required,” says Despommier. “Traditional greenhouses are linear, with little pitched roofs, side by side. There’s nothing inside that differs from a normal farm in the way they handle water and waste. It’s simply an indoor version of an outdoor farm. It’s not sustainable.”
The challenges of vertical farming are not so much in coming up with something new, as in putting them all together; a process Despommier likens to having motors, wheels, windows and lights, and suddenly realizing you could build a car.
How it works
Vertical Farming combines the latest high-tech with the oldest practice of settled societies – growing food. And while it promises yields of more than 40 times the amount grown using traditional methods, successfully growing food indoors and off the ground also requires that we synthesize an array of cutting edge technologies:
Aeroponics. In vertical farming, soil is a thing of the past. The latest aeroponic systems have plants’ roots dangling in a computer-controlled mist which provides exactly the right amount of nutrients and moisture. Plants grow three to four times faster while using much less water. And removing all that heavy soil from the equation, means lighter “fields” – a major advantage for the vertical farm.
Electrochromic Glass. By orienting the building toward the sun, the vertical farm will maximize natural solar light for the plants. Using electrochromic windows over much of the building - which can be darkened using low-voltage electrical currents - will allow vertical farmers to control exactly how much heat and light their plants receive.
Fiber optics and hybrid lighting systems. Scientists have discovered that different plants grow most efficiently under different frequencies of light. In a vertical farm, many plants would be shaded by the floors above them. Fiber-optic cables can efficiently transport light to the interior of the building, and multi-spectrum LED lighting systems can be designed to give the exact spectrum and amount of light for each crop, 24 hours a day.
Biogas Generation. To offset the five million dollars it will cost to run these lights for a year, the vertical farm will use waste food generated by homes and businesses. Current technology allows this biomass to be converted into dried pellets and burned. The copious amounts of methane gas which are then released can be converted to electricity in a fuel cell, with the heat from the reaction used to run refrigeration systems or control building temperature. Not only does this provide an overall 90 percent efficient renewable energy source, but it could provide an efficient disposal mechanism for the many tons of compostable garbage that are generated in the city each day, then hauled to landfills - at a significant financial and environmental cost. And because of the extraordinary efficiency of the vertical farm, this system could potentially generate extra electricity for the urban power grid.
Living Machines. New York dumps over a billion gallons of chlorinated wastewater into the Hudson river every single day. That’s right: a billion gallons. Every day. Despommier proposes using a multi-stage organic water filtration system, or living machine to treat this water for use in the vertical farm. “Zebra mussels are the size of your pinky finger, and each one processes a quart of water a day. A single square meter can hold 400,000 mussels which can treat 100,000 gallons a day. With baffles of these mussels in tanks, you run the greywater through, and by the time it comes out the last tank it’s odor-free and gin clear. You can filter it through charcoal, treat it with UV light, and it’s drinkable.” And while some view the mussels as an invasive species, Despommier argues that since we’re stuck with them, we might as well put them to use. IBM and NASA are currently investigating how to use similar methods to recycle water on spaceships.
Evapotranspiration. The vertical farm could grow more than food: it could be a water farm as well. Because plants thrive in a humid environment, the vertical farm will use gas-cooled tubes running across the roof of each floor to attract condensation of water. This process, called evapotranspiration, will allow the vertical farm to collect freshwater - potentially millions of gallons a year – which could be provided cheaply to the community, or sold to augment profitability.
If it works, it will spread
The Vertical Farm is thus an attractive - though untried - idea from a sustainable business perspective. But if it could be made to work in one city, it would very likely spread, and if introduced on a large scale, Despommier argues, it could have many benefits to society. For instance:
~Converting abandoned urban properties into food prodution centers to create ‘green-collar’ jobs
~Allowing farmland to be restored to natural ecosystems which would increase biodiversity and CO2 absorption
~ Dramatically reducing agricultural run-off, transportation pollution, and the incidence of infectious diseases
~Turning cruise ships into giant mobile farms which could be available for disaster relief, international aid, or refugee programs.
~Improving health and economic development in poor and less developed countries, reducing armed conflict over resources, and lessening population growth
~Using plants for more than food, the vertical farm could also be used to grow medicinal plants, flowers, herbs, or bio-fuels
Of course, to be effective, the project would also require an unprecedented level of collaboration among different industries, technologies, and social and regulatory agencies. But it is precisely this synergy which makes it a truly “green” idea. “Transforming cities into entities that nurture the best aspects of the human experience is the goal of every city planner,” states Despommier, “and with vertical farming serving as a centerpiece, this concept has a real chance to succeed.”
And he is not the only one who thinks so. Engineering giant Arup, fresh from building the elegant 2008 Olympic Stadium, is now embarking on a project to build the world’s first green city on an island outside Beijing. Dongtan is a bold experiment to design a city from the ground up which could serve as a revolutionary model for the urban expansion going on at break-neck speed across China. The designers’ plans call for clusters of superefficient buildings; walkable neighborhoods laced with canals and parks; an electrical grid completely powered by local, renewable energy; a system to recycle 90% of their waste; and, of course, the ability to grow their own food.
Just this summer, Arup formally approached Columbia University about integrating vertical farms into Dongtan. The Chinese, says Despommier, “are happy to invest in the R&D as long as we share the solutions, because their big question is: How are we going to feed the next generation?”
Despommier estimates it will be five years before the first vertical farms are up and running. “Last year I wouldn’t have said that.” If he is right, the future of farming has just taken a major leap forward. Ultimately, Despommier says, the current system of farming is inefficient. Dozens of government subsidies, tax-breaks and tarriffs are required to make farming profitable. “You’re looking at hundreds of billions of dollars just to make farming work. I’d rather spend that money showing cities how to survive in an ecologically sound manner.”
Despite the challenges of the idea, vertical farming makes too much sense to ignore. One way or another, it’s probably just a matter of time before lettuce and tomatoes are enjoying that south-facing view from the corner office on the 30th floor.