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Vertical Farms: From Vision To Reality


Renee Cho / State of the Planet 

Vertical Farms

Dr. Dickson Despommier laughs when he recalls how people thought he was crazy just a few years ago. But Despommier, the most passionate proponent of vertical farming—the growing of crops indoors in multi-story urban buildings—is now seeing his vision being realised. He believes vertical farming can help feed the growing global population and undo the environmental damage caused by conventional agriculture. 

“Farming has upset more ecological processes than anything else—it’s the most destructive process on earth,” Despommier told me. As of 2008, 37.7 percent of global land and 45 percent of U.S. land was used for agriculture. The encroachment of humans into wild land has resulted in the spread of infectious disease, the loss of biodiversity and the disruption of ecosystems. Over-cultivation and poor soil management has led to the degradation of global agricultural lands. The millions of tons of toxic pesticides used each year contaminate surface waters and groundwater, and endanger wildlife.

Agriculture is responsible for 15 percent of global greenhouse gas emissions, and accounts for one-fifth of U.S. fossil fuel use, mainly to run farm equipment, transport food and produce fertiliser. As excess fertiliser washes into rivers, streams and oceans, it can cause Vertical Farms eutrophication: Algae blooms proliferate; when they die, they are consumed by microbes, which use up all the oxygen in the water; the result is a dead zone that kills all aquatic life. As of 2008, there were 405 dead zones around the world. 

More than two-thirds of the world’s fresh water is used for agriculture. And around the world, farmers are losing the battle for water for their crops as scarce water resources are increasingly being diverted to expanding cities. As climate change brings warmer temperatures and more droughts, the water crisis will worsen. 

To feed the growing and increasingly urban global population of 9 billion expected by 2050, we need to boost food production by 70 percent through higher crop yields and expanded cultivation. The FAO estimates that we will need nearly 300 million more acres of arable land to do this, but most of the remaining arable land lies in developing countries, and many of the available land and water resources are currently providing other important ecosystem functions. Pressing them into service to produce food will upset many more of the planet’s ecosystems. 

In 1999, while exploring the negative impacts of agriculture, Despommier, a professor of environmental health sciences at Columbia University’s Mailman School of Public Health, and 105 graduate students came up with the concept of the vertical farm—a multi-story building growing layers of crops on each floor. Vertical farm crops can be grown using hydroponics, where plants grow in water or a growing medium with nutrients delivered directly to their roots; aeroponics uses a mist to deliver nutrients to plant roots; when fish are raised concurrently and their waste is used as nutrients for crops; or even in soil if the building is designed accordingly. 

Grown Crops in Vertical Farms

At present, lettuce, leafy greens, herbs, strawberries and cucumbers are the most commonly grown crops in vertical farms, but in theory, corn and wheat could be grown, as well as biofuel crops and plants used to make drugs. Hydroponics use 70 percent less water than conventional agriculture; aeroponics use even less; and all water and nutrients not taken up by the plants are recycled.

Climate controls and LED lights programmed to deliver the wavelengths of light that plants prefer create optimum growing conditions. Methane generated from restaurant or crop waste can supply energy and heat for vertical farms. 

As a balanced mini-ecosystem, the vertical farm has many advantages. A vertically farmed acre can produce the equivalent of 4 to 6 soil-based acres, depending on the crop (for strawberries, 1 vertical farm acre produces the same amount as 30 outdoor acres). Plants can be grown year-round, unaffected by weather conditions such as droughts, floods or pests. Vertically farmed food is safe from contamination (for example, from e-coli or radiation), and is grown sustainably and organically without the use of fertilizer, pesticides or herbicides. 

Fossil fuel use is minimal because there’s no need for farm equipment, transportation of produce into cities, storage or distribution. Unused urban buildings can be revamped as sustainable centres providing healthy food in neighbourhoods where fresh produce is scarce, and also creating new job opportunities. In war or disaster zones or refugee camps, modular vertical farms could provide much needed fresh produce. And if vertical farms were implemented on a large scale, we might one day be able to reclaim farmland and restore our soil, forests and ecosystems. Without fertiliser runoff, coastal waters could be revitalised and our fisheries might once again flourish. 

Some skeptics have said that the amount of electricity that would be needed to replace sunlight in vertical farms would be prohibitively expensive and unachievable. But Despommier counters that the cost of LED lighting is offset by savings from the elimination of fossil fuel use in fertiliser, transport, storage and distribution, as well as from less spoilage and waste. This, however, remains to be proven, since no one has yet done a life cycle cost comparison between vertical farm-grown crops and those produced conventionally. 

Another criticism, no doubt in response to early designs of futuristic vertical farms towering over a city, is that the steep capital investment needed is prohibitive and doesn’t make economic sense. Despommier himself acknowledges that integrating multiple stories of crop growing presents engineering issues that need to be solved. But why do vertical farms have to be in skyscrapers? 

One year ago, no vertical farms existed. Today the modestly sized vertical farms springing up around the world are proving the skeptics wrong... 

In Seattle, ecological designer Dan Albert and his wife run a 100-square-foot, two-level vertical farm called Civesca (the name is due to change) in a simple warehouse. They will begin selling their aeroponically grown salad greens, mustard greens, and kale to a few local restaurants on Nov 1st. 

Albert gives high praise to his aeroponics technology, created by Ithaca, NY-based AeroFarms. The modular system incorporates aeroponics, programmable LED lights, climate controls, and a proprietary horizontal cloth conveyor that takes the plants from seed to harvest. AeroFarms says its customisable system increases yield up to 60 times that of conventional agriculture, uses 80 percent less water than hydroponic systems and only 3 percent of the land required by conventional agriculture. 

For more about AeroFarms:

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