A Monthly Publication

By Joe Parker, agricultural ‘expert’

90% of the UK population lives in towns or cities. This is one of the highest proportions in the Northern hemisphere, out-stripping our European neighbours and dwarfing the percentage in China and India. This massive concentration of the population in urban areas brings with it a logistical problem for food distribution.

Coupled with this British farmers and growers produce only 58% of the food we eat, down dramatically from 75% in 1994. This is particularly the case for fruit and vegetables where we import 40% of the vegetables we consume and an astonishing 90% of fruit. This importation of food and the associated distribution network generates 19 million tonnes of CO₂ per year - 3% of the UK’s total greenhouse gas emissions; road freight being the main contributor. But congestion caused by road freight and cars travelling to and from supermarkets is the biggest cost.

By the year 2050, nearly 80% of the earth's population will reside in urban centres. Applying the most conservative estimates to current demographic trends, the human population will increase by about 3 billion people during the interim. An estimated one billion hectares of new land (about 20% more land than is represented by the country of Brazil) will be needed to grow enough food to feed them, if traditional farming practices continue as they are today. At present, throughout the world, over 80% of the land that is suitable for raising crops is in use. Historically, some 15% of that has been laid waste by poor management practices. What can be done to avoid an impending disaster?

The concept of indoor farming is not new, since hot-house production of tomatoes, a wide variety of herbs, and other produce has been in vogue for some time. What is new is the urgent need to scale up this technology to accommodate another three billion people. An entirely new approach to indoor farming must be invented, employing cutting edge technologies. The ‘vertical farm’ must be efficient, cheap to construct and safe to operate. Vertical farms, many stories high, will be situated in the heart of the world's urban centres. If successfully implemented, they offer the promise of urban renewal, sustainable production of a safe and varied food supply and the eventual repair of ecosystems that have been sacrificed for horizontal farming.

It took humans 10,000 years to learn how to grow most of the crops we now take for granted. Along the way, we despoiled much of the land we worked, often turning verdant, natural eco-zones into semi-arid deserts. Within that same time frame, we evolved into an urban species, in which 60% of the human population now lives vertically in cities. This means that, for the majority, we humans are protected against the elements, yet we subject our food-bearing plants to the rigours of the great outdoors and can do no more than hope for a good weather year; more often than not, due to a rapidly changing climate regime, that is not what happens.

Massive floods, protracted droughts, class 4-5 hurricanes, and severe monsoons take their toll each year, destroying millions of tonnes of valuable crops. The time is at hand for us to learn how to safely grow our food inside environmentally controlled multi-story buildings within urban centres. If we do not, then in just another 50 years, the next 3 billion people will surely go hungry, and the world will become a much more unpleasant place in which to live.

The requirement to rethink how we grow and distribute food in an urban dominated society has stimulated some eminent scientists to question the whole production cycle. The concept of vertical farming has captured the imagination of architects around the world to design “skyscraper farms”. In conjunction with researchers in hydroponics, waste management and environmental control systems they have designed a series of potential solutions.

Feasibility studies have been carried out to design buildings capable of supplying enough fresh fruit, vegetables, poultry, eggs and even grain for 50,000 people. These buildings are designed to be carbon neutral throughout the production cycle. One example proposed for Dubai designed by two Italian architects uses seawater to cool and humidify greenhouses and to convert sufficient humidity back into fresh water to irrigate the crops. To reduce the carbon footprint of each seawater vertical farm, each of the pods is covered with a transparent polymer-type membrane that allows sunlight in, negating the need to install electrical growing lights overhead.

Although these plans may seem futuristic, the concept of incorporating internal growing areas into modern multi-story buildings can be seen in the design for Vauxhall Bridge Gardens. This building has already received planning permission. The site at Vauxhall Cross lies within the Greater London Authority’s newly designated Nine Elms Opportunity Area. Although not vertical farming, this design incorporates 2,500m² of communal ‘sky-gardens’, each being three stories high. It doesn't take much of a stretch of the imagination to see how these could become communal allotments providing fruit and vegetables for the residents.

But the idea of growing crops in a vertical plane has taken another step forward recently. Valcent Products Inc. has achieved a critical milestone with the successful launch of the company's first full scale commercial vertical farming system at Paignton Zoo. According to Chris Bradford, managing director of Valcent, a 100m² machine, like the one installed at Paignton Zoo, can grow up to 11,200 plants per crop, which he says, is potentially 20 times more than could be grown conventionally in a field covering the same area.

These self contained systems rely on novel hydroponics, LED lighting and climate control technology to grow produce in a vertical plane. ‘VertiCrop’ is a high density, vertical growing system, which maximizes the potential of available growing space and can eliminate the need for pesticides and herbicides. VertiCrop’s sophisticated hydroponics system is capable of achieving astonishing yields, using up to 95% less water than in conventionally irrigated poly-systems. Crops are continuously rotated within the machine, ensuring an even exposure to light, nutrients and creating a constant air-flow.

Valcent's success at Paignton Zoo shows that this is now possible to grow leafy vegetables on a commercial scale. But can this technology by transferred to the farm and would it be possible to convert an existing farm building? "We are looking to convert an existing tractor shed into a full scale vertical farming system producing salad vegetables for the UK market", says Graham Dunling of Valcent. This will meet an increasing demand as suppliers have realised the need to reduce the carbon footprint of salads imported from Southern Europe. It is possible to grow 12 crops per year of baby leaf salad for example and using a six-metre high module the income generated can exceed £150,000 per module.

An innovation such as vertical farming could have multiple benefits for the food industry. It would allow an alternative source of income for farmers without the need to change their land use practices and would permit land to be taken out of production to meet environmental requirements without the fear of loss of income. It would stimulate the local economy and provide a new source of year round fresh produce without the associated food miles and with a much reduced carbon footprint.