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The Rise of Indoor Cropping

By Tess Riley 

It’s commonly accepted that record food prices were one of the key triggers for the Arab Spring. This year in Zimbabwe, critical levels of crop failure put over two million people at risk of chronic malnutrition. Even a prosperous state like Singapore, which imports over 90 percent of its produce, is starkly aware of its food security risks. Water scarcity, erratic weather conditions and a burgeoning global population, with rising expectations of living standards and an increasingly carnivorous diet, is driving pressure across the food chain. As food producers look for ways to boost productivity and safeguard their crops from an unpredictable climate, has the time come to take agriculture indoors?

Fly over Holland and you’ll find yourself looking down on a sea of glass; here, hydroponic greenhouses account for 50 percent of the value of all fruit and vegetables produced in the country – a practical response to soil depletion, disease and salinization. Making plants less vulnerable to soil degradation and unpredictable weather is just one advantage of indoor cropping; it also offers horticulturalists more control over the conditions, allowing them to drive efficiency, reduce waste and expand production beyond seasons. The potential environmental benefits of this are significant: the assumption that the greenest farming is done outdoors needs to be challenged.

The variety of cultivation and irrigation technologies available – as well as ways to harvest key resources, from water to light – makes indoor cropping a diverse practice. While it’s not a given that every indoor project will be high tech, the enclosed environment lends itself well to bio-control technologies. The exceedingly efficient LED lighting new to the market, for example, allows for year round food production in previously unsuitable climates. Horticultural business consultant John Hall also points out that this kind of technology opens up opportunities to those who want to grow veg, specialist herbs and young plants.

Trials sponsored by Dutch company Philips Lighting and British company CambridgeHOK in Yorkshire explored the potential benefits that LED technology could have for the future of vertical farming: enhanced yield was one of them. Where a normal lettuce grower might produce five crops a year, this system can produce 15, according to Graham Ward, CEO of Stockbridge Technology Centre (STC), where the LED4CROPS trials took place. Martin McPherson, Science Director at STC, predicts that as this technology is developed it will offer increasingly good returns on investment:

“The technologies and costs associated with LED lighting in a multi-tier environment are anticipated to change over the next few years to make it increasingly attractive to growers and investors. Early indications from our work suggest that there are considerable opportunities to improve yield and crop quality through manipulation of the light spectrum. In the case of vertical farming, it’s important to think inside the box.”

Another technology gaining traction from China to Chile, and already dominating agriculture in the Netherlands, is hydroponics. These soilless systems offer crops just the right amount of water and nutrients, and recycle these, without any nutrient leaching (a concern for traditional outdoor farming in which chemicals contaminate groundwater reserves). Simon Billing, an expert on sustainable food at Forum for the Future, says, “The hydroponic system is the nearest thing to a closed loop system that I have seen in agriculture. Most of the systems use virtually no pesticides and biological controls; green waste is reused and there’s no water or nitrogen loss. It’s amazingly efficient – and yet you can’t currently register it as organic in the UK, as it’s not in soil.”

Farms have traditionally been a significant contributing factor to global problems of water pollution and scarcity, but now innovation is turning the tables. In the arid desert outside Port Augusta, South Australia, Sundrop Farms are working on a project which uses solar energy to desalinate seawater for irrigation, enabling them to grow cheap, high-quality vegetables without pesticides all year round. Head over to Singapore and you’ll be able to visit Sky Greens Farms, the world’s first commercial vertical farm, which stretches 30 feet into the sky to produce crops sold in local supermarkets. In Chicago, the FarmedHere urban farming company puts derelict warehouses to good use, growing more than one million pounds of herbs and micro greens per year using a combination of aquaponics and aeroponics.

Much of the industrial-scale indoor production of fruit and veg goes on in colossal glass complexes. Thanet Earth in Kent is the UK’s largest and most high tech. Here, row upon row of salad crops are meticulously grown under 55 hectares of glass using hydroponics. A central computer system determines optimum light and heat levels, energy is generated on site, and an army of bees and ‘good’ bugs ensure pollination and adequate pest control. The result? Thanet Earth is expected to increase UK salad crop (cucumbers, peppers and tomatoes) production by 15 percent. It harvests 700,000 cucumbers, 750,000 peppers and millions of tomatoes every week during the crops’ impressive growing seasons. In the case of tomatoes, that growing season just happens to be all year round, indifferent to the bitter winters, Indian summers and intense rainy periods making their presences felt outside.

Whatever the scale, these projects aren’t cheap. Thanet Earth, for example, has planning permission to build a total of seven greenhouses at a projected cost of £135 million; stakeholders include the UK’s largest privately owned fresh produce supplier, Fresca Group Ltd, and specialist grower companies, the majority of which are Dutch.

By contrast, in the Mediterranean city of Almería, southern Spain, sweet peppers, aubergines and other vegetables thrive under unheated plastic structures installed by the likes of Enza Zaden, an international plant breeding company. Costly glass structures and the high energy demands to heat them just aren’t necessary in places like southern Europe and Africa, where the future of much indoor cropping appears to lie.

The critical question is whether this trend will help or hinder sustainable food production at scale. Kevin Price, Corporate Marketing Manager of the crop protection company Certis Europe, says: “Protected cropping, if done well and with foresight, will be an important contributor to a sustainable food system. It will prove important for food security in providing a range of nutritiously rich crops while protecting the crop against a variable climate.” Why the need for foresight? The main concern is energy use, particularly in Northern Europe. According to Billing, the European greenhouse sector consumes as much energy as Sweden. It’s all very well enjoying a local tomato but if the carbon footprint of what you’re eating is higher than its imported equivalent, something’s not right. To date, some efficiency gains have been made, but the predominant indoor scenario still sees massive losses as heat is pumped into glass or plastic.

The good news is that the rush to tackle this problem is on and innovative solutions are being put into practice, from making use of renewables, like ground source heat or biomass, to combined heat and power systems (Thanet Earth uses such a system to generate electricity, feeding excess back into the National Grid). Later this year, Lufa Farms is set to open its second rooftop urban farm just north of Montreal, Canada, spanning 43,000 feet above a commercial property, which enables it to make use of the heated building below to keep crops warm. This means it will require only half the energy per square foot to grow food compared with a conventional farm on the ground. The Dutch Government is also investing in efforts to reduce energy costs and use: it currently subsidises its gas market to support growers, with horticulture its biggest export.

Will future generations look back and ask us why we didn’t move crops inside sooner, in a world of ever more extreme weather events and critical food security concerns? Simon Crichton, Food and Organic Farming Relationship manager at Triodos, remarks that many growers in the UK would have gone out of business in 2012 without the advantages of protected cropping. “The focus globally now has to be on eliminating the use of fossil fuels,” he adds. “I’m pleased to see people starting to innovate with sustainable heat sources. If we can tackle this energy question, protected cropping will be able to play a role in sustainably extending seasons, increasing the number of available crops and protecting against variable climates to the benefit of food supply worldwide.” 

Photo credit: Flickr

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