Singapore is both a city and a nation on a relatively small island in southern Asia near the equator. By area, Singapore is smaller than all five boroughs of New York City, but must supply basic needs, including food and water, to its 5.4 million residents.
One potential solution to Singapore’s need to grow crops on scarce land is vertical farming.
Sky Greens, a young company in Singapore, has developed a patented vertical farming system with rotating growing troughs that are mounted on an A-frame made of aluminum. A farm consisting of 1,300 A-frame towers, each up to 30 feet tall, is growing six varieties of lettuce in northwest Singapore.
The company estimates it can get 10 times the yield from such a system, compared to a conventional farming method on the same area of land.
On a recent tour with other reporters, I got to see the operation first hand. The troughs rotate a full cycle over 16 hours, getting water at the bottom of the journey and then advancing higher to get sunlight from all angles. We sampled the end product, which was a sweet, slightly crunchy (and fresh!) salad, made primarily of mizuna and other greens.
The system takes advantage of a rich soil concentrate that includes fertilizer made chicken manure. It can also be set up for hydroponic operation, without using soil.
Sky Greens CEO Jack Ng and Roshe Wong Kok Leong, the company’s business development manager, said the company has a vision of operating three vertical farms in coming years to produce enough green vegetables that Singapore won’t need to import any.
So far, the operation in Singapore isn’t automated, other than using electricity to move the troughs up and down. In the future, it could be fully controlled much the same way as other manufacturing facilities. The labor is primarily provided by workers from Bangladesh, the company said.
In the fashion of many young Singapore tech companies, Sky Greens has a fairly utopian vision for its vertical farms. In one example, the company wants to put its growing towers atop urban high rises where parking spaces might be located. A longer-term vision is to build an “agripolis,” where towers growing a variety of crops would be paired with vertical hatching stations for chickens and other animals. Three such agripolises could supply nearly all of Singapore’s demand for green leafy vegetables.
Today, Sky Greens’ lettuce is sold in a single market chain, where the price is about 20% above the cost of other leafy vegetables. Consumers are willing to pay more for the goods because it is tasty and very fresh -- usually just a day old.
Once the capital costs are paid off, the price of vertical farm lettuce could be less than imported lettuce. The cost of erecting one 30-foot-high tower with 38 tiers of growing troughs is about $11,000. Sky Greens wants to expand its current operation to 2,000 towers, reaching a total cost of roughly $26 million.
What seems most obvious about the Sky Greens venture is how important it has become for Singapore to become food independent. The country began moving toward water independence over several decades, going from importing nearly all of its water in the 1960s to cutting that amount to less than half in recent years.
The water initiative came after the country embarked in the 1970s on an ambitious plan to clean up its rivers and to capture rainwater by setting up a series of reservoirs. In 2008, the Marina Barrage dam was opened across the Marina Channel near a dense urban area of high rises and at the confluence of five rivers. The Barrage helps with flood control in nearby streets where more than 150 drain sensors are installed. The sensors detect if flooding is imminent and will tweet out warnings to residents to take precautions.
Singapore also desalinates water and recaptures gray water with the use of membrane technology to create what it calls "New" water, which can be used for watering plants and a variety of other purposes.
Because Singapore is a small island nation, it's easy to see why water and food independence are major imperatives. As the world’s geo-political situation evolves in coming years and the nation becomes potentially more vulnerable, Singapore seems to be taking steps that should make it mostly self-reliant. Self-reliance was an imperative invoked by the nation’s beloved first prime minister, Lee Kuan Yew, who died last year. Average citizens and companies based in Singapore like Sky Greens seem to have taken Lee’s vision to heart.