May 17, 2016
By: Conrad De Aenlle
It is a staggering challenge: feeding the seven billion-plus people in the world and delivering fresh food to the rapidly rising number of them who live in cities.
One solution, more theoretical than practical so far, amounts to killing two birds with one stone and adding a third benefit: vertical farming.
By growing crops on the sides or roofs of buildings, or in stacks inside, in the large cities where they will be consumed, food can be produced in a way that saves energy and time, proponents of vertical farming assert.
The advantages will become even clearer, they say, as techniques and technologies improve, urban populations expand and factors such as increasing water scarcity and climate change hamper traditional flat-earth farming.
“Growing outdoors is more challenged than ever before, especially when you layer in the increasing volatility of weather and climate change and issues of food safety and pesticides,” said Marc Oshima, marketing director and co-founder of AeroFarms, a New Jersey company that produces leafy green vegetables and herbs on 30,000 square feet (about 2,800 square meters) of vertical farms in Newark. “We need a new paradigm. Vertical farming gives us control over a lot of these variables.”
They are the same variables that any farmer hopes to control, including water, light, the growing medium and the insects and other pests that might reduce yields.
AeroFarms, which expects to operate 25 facilities of 45,000 to 60,000 square feet each all over the world in five years, uses a closed-loop irrigation system that allows food to be grown with 95 percent less water than conventionally cultivated vegetables, Mr. Oshima said. Using light-emitting diodes instead of sunlight means that a growing cycle takes about two weeks, allowing for up to 30 harvests a year and resulting in 75 times greater productivity per square foot, he said. And because its Newark farm is indoors, there are no bugs or rodents to contend with.
“Nothing touches the plant,” he said. “With the right lighting spectrum, we can optimize for taste, nutrition, texture and color.”
AeroFarms uses repurposed warehouse space for its farms. Plantagon International, a Swedish company designing prototype farms with real estate developers, government authorities and universities around the world, hopes to incorporate its farms into multipurpose buildings.
Plantagon intends to make vertical farming more efficient through various forms of symbiosis. It plans, for instance, to integrate farms into ventilation systems, delivering oxygen produced by plants to a building’s human occupants and sending the carbon dioxide they exhale in the opposite direction.
Hans Hassle, chief executive of Plantagon, explained how two projects underway in Sweden will try to keep energy costs down by warming the buildings housing the farms with heat thrown off by the artificial lighting. That’s a sensible idea — in Sweden. Mr. Hassle conceded that the excess heat from a farm that Plantagon is building in Singapore would not be put to such effective use.
“Vertical farming won’t be proven until we see the technology working and the business model working in different markets,” he said.
Proven or not, vertical farming has existed for more than 100 years, often on the pages of books and magazines spitballing ideas for creating a utopian society. What is believed to be the first vertical farm in the real world was a hydroponics facility built in Armenia sometime before 1951.
Commercial vertical farming expanded after the 2011 earthquake and tidal wave in Fukushima, Japan, destroyed a substantial amount of cropland, said Dickson Despommier, emeritus professor of public health and microbiology at Columbia University.
“Japan has emerged as a leader in vertical farms,” Mr. Despommier said. “There are 150 or so, all commercial, producing crops for mass consumption. The government poured lots of money into projects, and universities and corporations helped. The next thing you know, they were up and running.”
Vertical farms also can be found in fairly large numbers in Taiwan, Singapore and the American Midwest, he said. In one conspicuous example in Europe, the United States Pavilion at Expo 2015 in Milan featured fields of leafy vegetables on its outer walls.
How much food comes from vertical farms is hard to calculate, though it is thought to be a very small fraction of all food grown. The United States Department of Agriculture keeps no statistics on production from vertical farming, according to a spokesman, Damon Thompson, but the agency is about to issue an “urban agriculture toolkit,” available online for anyone interested in pursuing the practice, he said.
One reason that vertical farming remains a small, obscure niche is that farmers need to make money, not just food. Mr. Oshima said that AeroFarms was “cost competitive today with the field farmer.” But vertical farming has many skeptics and critics who expect that whatever energy and money are saved by shortening the distance from farm to table to be lost, and then some, by the high cost of artificial lighting and other equipment needed to produce food indoors and even outdoors in many urban settings.
It may be feasible to grow certain crops efficiently in certain circumstances in certain settings, they say, but only to a certain extent and at certain times. They consider it unlikely for the foreseeable future that vertical farming could produce enough food of different varieties to feed a significant number of people in a commercially viable way.
“It’s such an appealing idea — ‘Press Floor 10 for lettuce’ — that people picked up on it right away,” said Bruce Bugbee, a professor of crop physiology at Utah State University. “The fundamental problem is that plants need a lot of light. It’s free outside. If we’re going to do it inside, it will require the burning of a lot of fossil fuels. Vertical farming is fine if you’ll let me have a vertical nuclear reactor next to it.”
If that’s not an option, then success in urban vertical farming is likely to be confined to a small number of crops, such as the varieties that AeroFarms cultivates.
“There are situations in dense urban areas where space is highly limited that growing food with artificial lights, stacked vertically, makes sense, especially highly perishable products like sprouts or salad greens where there is an immediate market for them,” said Stephen J. Ventura, a professor of environmental studies and soil science at the University of Wisconsin.
“The local-food movement has made people more aware of where their food is coming from and helped create a general trend toward more production in and around cities,” he added. “That has led to innovations for relatively small-scale urban farming and people growing oregano and basil on a stoop. Whether we build dedicated buildings for vertical farming, I’m skeptical.”
Mr. Ventura also pointed out that the middle of nowhere and the middle of Broadway aren’t the only possible locations for food production. Many cities have arable land on the outskirts of town that is far cheaper than prime urban real estate and close enough to consumers to keep shipping costs and logistical headaches to a minimum.
Mr. Hassle, at Plantagon, acknowledged that whatever problems may be solved, producing food in the heart of a city can create other difficulties. There’s more to making a vertical farm successful than growing crops.
“It’s not just one thing that has to happen,” he said. “If you’re going to grow inside a city, there won’t be farmers standing there waiting to buy products. We’re trying to find bulk buyers that don’t add a lot of transportation to a city.”
The challenges of doing vertical farming profitably on a large scale are so daunting that even a true believer like Mr. Hassle can’t help but be skeptical.
“Vertical farming as an industry is very much at the beginning,” Mr. Hassle said. “We have focused on making it industrial and scalable, and that’s a little bit crazy. It’s like trying to do the impossible. It looks almost like science fiction.”
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