Growing upwards

With a global food crisis apparently looming, a group of scientists is advocating an innovative alternative to conventional farming that could radically transform the way that food is produced. Maryrose Fison investigates
Picture a farm, and a freshly ploughed field may spring to mind: brown soil ridged with neat furrows that turn gold as the sun sets. Or perhaps it’s harvest time and the earth has been transformed into a sea of green, lettuce leaves colliding as far as the eye can see.

Unfortunately, such images may not exist for much longer. With intensive farming and climate change wreaking havoc on farmland, fertile soil is rapidly being eroded and new land becoming ever more sparse. A recent study by the Government Office for Science in London’s Foresight Project found that 24 per cent of the world’s 11.5 billion hectares of vegetated land has already undergone human-induced soil degradation, particularly erosion. It goes on to warn that urbanisation, desertification and sea-level rises are all putting further pressure on the world’s agricultural land.

Mouths to feed
The global population is expected to exceed nine billion by 2050 – a rise of a third from today’s level – and studies suggest that food production will have to increase by 70 per cent if we are to feed all of those new mouths, meaning that new ways of growing crops will have to be developed if we’re to avoid a humanitarian crisis. Indeed, UN Food and Agriculture Organization figures suggest that the number of undernourished people is already rising. And as global warming begins to bite, crop yields in many areas have been projected to fall.

With this in mind, some scientists and agricultural experts are advocating an innovative alternative to traditional farming that promises to boost crop yields many times over while returning overused farmland to Mother Nature. Skyscrapers packed with shelf-based systems for growing vegetables on each storey – known as ‘vertical farms’ – hold the key to not only revolutionising food production but dramatically cutting fossil-fuel use and reducing geopolitical tensions in countries where poor farming conditions cause conflict and malnutrition.

A single 20-storey vertical farm could theoretically feed 50,000 people, accor­ding to Columbia University professor Dickson Despommier, who has published a book on the subject – The Vertical Farm: Feeding the World in the 21st Century – and serves on the City of Chicago’s Technical Advisory Group for Vertical Farming. If the theory translates into reality as proposed, 160 skyscraper-sized vertical farms could feed the entire population of New York City, 180 would be needed to feed London, 289 to feed Cairo and 302 to feed Kolkata.

It’s a compelling vision, and one that has already been put into practice in Asia, albeit on a smaller scale. In Japan, the Ministry of Agriculture, Forestry and Fisheries (MAFF) sees vertical farms as having a ‘complementary’ role to traditional outdoor-based farming and is already implementing a number of support options for those wishing to pursue the technology.

‘The advantage of using indoor vertical farms is that we can grow vegetables without [the] aftermath of climate change,’ says a MAFF spokesperson. ‘But there are problems, such as initial investment and operating costs [that] are too much.’ This hasn’t stopped MAFF promoting the tech-nology in vertical farms, and the ministry has launched a training course for food producers.

Tokyo-based mushroom producer Hokuto Corporation is a model example of how a vertical farm can run successfully. With 28 vertical mushroom farms operating across the country, it produces some 68,000 tonnes of mushrooms annually.

According to Ted Yamanoko, head of marketing and research at Hokuto, the company’s mushroom facilities are cost-effective and environmentally friendly. ‘As far as mushrooms are concerned, vertical farms without soil have more advantages than ground-level farms with soil,’ he says. ‘There is also less of a carbon footprint.’

Salad days

It may not be long before overseas companies begin to follow suit. This summer already marks the two-year anniversary of the UK’s first vertical farm. But unlike Hokuto, it caters to the palates of four-legged customers, rather than the two-legged variety.

Cornwall-based Valcent Products’ vertical crop-growing system, known as VertiCrop, is currently producing 134,400 leaf vegetables annually at Paignton Zoo in Devon, contributing to the diets of 20 per cent of the zoo’s 2,500 animal inhabitants. Kevin Frediani, curator of plants and gardens at the zoo, says that he has been impressed with the system, which allows 11,200 individual plants to be grown hydroponically (a process that allows plants to grow in nutrient-enriched solution instead of soil) on a four-week harvesting cycle, and can see it having applications outside of the zoo industry.

‘The area available to grow plants in is 20 times what you get in a field-based system, and you’re growing year-round, so you are multi-cropping,’ he explains, ‘whereas in a temperate country, we would get perhaps two crops of salads out of a field on a six-week cycle over the summer season.’

The structure in place at Paignton Zoo comprises a vertically integrated system of plants set over eight levels stacked three metres high. Beans, spinach and lettuces are grown on the trays, which are suspended from an overhead track and rotated on a closed-loop conveyor.

Because the system is entirely self-contained, all of the water used in irrigation is recycled, meaning that the farm uses one 16th of the water necessary in an outdoor farm while producing many times more crops. About 100 lettuces can be grown in a one-square-metre, three-metre-high vertical farm and 250 can be raised in a system twice as high – considerably more than the average of ten lettuces that grow outdoors in the same space.

Not only has the system substantially reduced the zoo’s £250,000 annual food bill, it has also cut down on food miles because the crops can be harvested on site and fed to animals within 15 minutes. Frediani believes that its applications could be transferred to producers of food for humans. ‘There’s great potential for these within an urban setting,’ he says. ‘You could see them in skyscrapers in urban areas.’

It’s little wonder that Chris Bradford, managing director of Valcent Products, has a number of contracts pending for the system, including from companies in regions where extreme climatic conditions have made traditional farming virtually impossible. The company is currently undertaking trials for a major European food producer that he says could lead to the technology being put into full-scale commercial production. ‘If the trials are successful and they decide to introduce the technology into their organisation, it will result in multiple orders for us for the VertiCrop system,’ he says. ‘We’re looking at not hundreds, but thousands of tonnes of produce per annum.’

The sky’s the limit

But it isn’t only about increasing food production – vertical farms could potentially have other benefits. ‘The challenge that we have now is not only to think about how we can produce food and food security,’ says Natalie Jeremijenko, an associate professor at the Environmental Health Clinic at New York University, ‘it’s how we can design urban agriculture systems that not only reduce food miles, but also improve environmental health and augment biodiversity.’

By significantly reducing the amount of land required for food production – and, in particular, allowing for the return of more marginal land to its natural state – vertical farms could help to preserve biodiversity, argue its adherents. This, in turn, can help to improve the productivity of conventional farms, as the health of agricultural land is often tied to the health of the surrounding ecosystems.

There’s an inescapable aura of science fiction surrounding vertical farming – skyscrapers dotted around major metropolises providing fresh produce for the cities’ inhabitants – but as VertiCrop and the Hokuto Corporation are demonstrating, there’s every reason to believe that they are feasible. And as the world wakes up to the reality of global climate change, it may be that the science fiction of vertical farms will become the only viable solution to the problem of feeding the world.

Food drops of vertical crops

Vertical-farm applications extend beyond feeding established urban populations. Professor Dickson Despommier sees them as potentially being capable of helping centres of displaced persons – such as refugee camps – in much the same way that Mobile Army Surgical Hospital (MASH) units are deployed in emergency situations.

‘Developing a MASH-like emergency-response system for crop production inside specially constructed modular and highly transportable greenhouses would allow for humanitarian interventions at least for refugees that are forced out of their countries by political turmoil,’ he says. ‘If you have three or four storeys of food already growing some place, they could become mobile units that could be picked up by a helicopter and dropped into the middle of a crisis zone. The food would be ready to pick and eat. It could be designed to supply people with all the nutrition they need to make it through the crisis.’

September 2011

Members Logon

user name


join nowforgot password