With its dry desert climate, the UAE may seem an unlikely place to find row upon row of succulent lettuces growing for the dinner tables.
Yet there are farms in the country where these leafy vegetables are successfully being grown, although the methods used are often far removed from traditional agriculture.
The secret is hydroponics, a technique that involves growing crops without soil, the plants instead securing the nutrients they need from special solutions.
Over the past decade, the method has become increasingly popular in the Emirates, not least because it helps save water, one of the country’s most prized resources. There are other benefits, too: not only do plants grow quicker, you get more of them from the same amount of land.
Among the country’s largest hydroponics agricultural producers is Emirates Hydroponics Farms (EHF) between Abu Dhabi and Dubai.
The farm, operated by an Australian company on behalf of an Emirati owner, grows lettuces and other herb crops in its greenhouses and, in the winter months, outside.
Other UAE hydroponics specialists include Salata Farms in Ras Al Khaimah and regional operator Pegasus Agritech, headquartered in Dubai.
“With local producers, a lot [of crops are] grown in the ground, but in the UAE, particularly Abu Dhabi … they’re pushing to convert farms to hydroponics,” said Rudi Azzato, EHF’s horticulturalist and marketing director.
Indicating the authorities’ enthusiasm for new methods of agriculture, in Abu Dhabi the Khalifa Fund for Enterprise Development has offered incentives for farms to convert to low-water methods, such as hydroponics.
The water savings hydroponic methods offer are little short of dramatic. To produce one kilogram of lettuce, for example, EHF requires a little over 20 litres of water, while traditional methods are said to use almost 400 litres.
In typical hydroponics systems, up to 80 or even 90 per cent of the water can be reused – rather than simply seeping into the ground as with traditionally planted crops.
Yet it is not just the water savings that makes hydroponics attractive, according to Mr Azzato.
“If you are growing in the open field, you will require a large land area … Growing in the ground for lettuce, you might, with a 12-month cycle, [have] five to six crops. With hydroponics, you would require a smaller footprint area to produce perhaps 18 crops per year,” he said.
The improved growing rate partly stems from the fact that with hydroponics, it is easier to create perfect conditions for growth: light, temperature, carbon dioxide and nutrient levels can be more precisely controlled than when plants are grown in soil.
“You’ve got very good quality control. You’re controlling the environment. It’s better quality control and more crops, more fruits produced per season,” said Dr Neil Bricklebank, a senior lecturer in inorganic chemistry at Sheffield Hallam University in the United Kingdom who is researching methods to improve the nutrient quality of hydroponically grown crops.
Research into hydroponics largely began in the 1920s and since then, a variety of methods have been developed.
With lettuces, the plants may be grown on a kind of tray, the roots dangling down into a nutrient solution. Several types of media are also used for growing, among them rock wool, made of fibres created from volcanic rock, along with potting mix and perlite, a rock heated to make it expand.
There are hurdles, though. In cooler regions, such as northern Europe, you need extra lighting and heating in your greenhouses, making production less cost-effective than in, say, Mediterranean nations such as Morocco.
In the UAE and other parts of the Gulf, the challenge is, of course, the opposite: the intense heat.
“To combat that, the best way would be to have a fully air-conditioned greenhouse similar to what people have in their homes, but is it feasible in infrastructure costs and running costs and maintenance costs?” said Mr Azzato.
While EHF does have a fully air-conditioned facility that allows 12-month production – Mr Azzato describes the company as an “R&D hydroponics farm seeing what works and what doesn’t in this country” – in many of its greenhouses, EHF instead uses a combination of waterpads and, at the other end of the greenhouse, fans, which aid cooling and maintain optimal growing conditions.
Dr Howard Resh, a US-based hydroponics consultant, has also been using evaporative cooling pads in similar projects around Riyadh in Saudi Arabia. But they are not suitable everywhere, he says.
“On the coastal regions where relative humidity is high, it will be much more challenging to reduce temperatures,” he said.
Areas of the Gulf region where humidity is lower offer “great potential” for hydroponics, he said.
With the world’s population set to reach eight billion by 2025 and nine billion by 2050, some believe hydroponics will have to be adopted ever more widely.
“In the next 50 years, it’s predicted we won’t be able to feed everybody on the planet unless we make serious changes to agricultural production,” said Dr Bricklebank.
“We’ll have to look at new ways to increase yields. Hydroponics is one method to do that. It’s one method which we could move towards.”
Already, the world is seeing a flurry of interest in high-yield “vertical farms” in which racks of plants are piled one on top of the other, with hydroponic systems used to provide water and nutrients, and light-emitting diode (LED) lights allowing the plants to photosynthesise.
At one such vertical farm, opened earlier this year in a former factory in Scranton, Pennsylvania, six racks of plants are stacked on top of each other, meaning that yields are many multiples those of traditional agriculture for a given area.
LED lights are however typically less than one-third efficient at converting electricity into light, limiting the cost-effectiveness of these methods.
As yet, Dr Resh says growing crops without sunlight is usually “not economically feasible”, especially for vine crops such as tomatoes and peppers. But with researchers at Philips said to have developed LED bulbs with 68 percent efficiency, that might change – and the spread of hydroponics could accelerate yet further.