Farming in the sky in Singapore
Tuesday, 11 December 2012
Asia Times, Hong Kong (Online)
SINGAPORE - With a population of five million crammed on a landmass of just 715
square kilometers, the tiny republic of Singapore has been forced to expand
upwards, building high-rise residential complexes to house the country's many
Now, Singapore is applying the vertical model to urban agriculture,
experimenting with rooftop gardens and vertical farms in order to feed its many
Currently only 7% of Singapore's food is grown locally. The country imports
most of its fresh vegetables and fruits daily from
neighboring countries such as Malaysia, Thailand and the Philippines, as well
as from more distant trading partners like Australia, New Zealand, Israel and
An influx of immigrants has resulted in a rapid crowding of Singapore's
skyline, as more and more towering apartment buildings shoot up. And meanwhile,
what little land was available for farming is disappearing fast.
The solution to the problem came in the form of a public-private partnership,
with the launch of what has been hailed as the "world's first low carbon,
water-driven rotating vertical farm" for growing tropical vegetables in an
The result of a collaborative agreement between the Agri-Food and Veterinary
Authority of Singapore (AVA) and a local firm, Sky Green, this venture aims to
popularize urban farming techniques that are also environmentally friendly.
With a robust economy that boasts a gross domestic product of US$239.7 billion,
Singapore has plenty of money. "But money (is) worthless without
food," according to Sky Green Director Jack Ng.
"That's why I wanted to use my engineering skills to help Singapore
farmers to produce more food," Ng told IPS.
An engineer by training, Ng created the vertical farming system, which he
nicknamed "A Go-Grow". It consists of a series of aluminum towers,
some of them up to nine meters high, each containing 38 tiers equipped with
troughs for the vegetables.
In keeping with Sky Green's focus on environmental sustainability, the water
used to power the rotating towers is recycled within the system and eventually
used to water the vegetables. Each tower consumes only 60 watts of power daily
- about the same amount as a single light bulb.
Ng knew that if the system was too expensive or complicated, urban farmers
would not be able to survive. And given that he designed the project with
retirees and other housebound farmers in mind, he tried to create a situation
in which "the plant comes to you, rather than you going to the
The multi-layered vegetable tower rotates very slowly, taking some eight hours
to complete a full circle. As the plant travels to the top it absorbs ample
sunlight and when it comes back down it is watered from a tray that is fed by
the hydraulic system that drives the rotation of the tower.
This closed cycle system is easy to maintain and doesn't release any exhaust.
Ng says that such towers, if set up on roofs of the many multi-story
residential blocs that house most of Singapore's population, could provide
livelihoods for retirees and housewives, who would only need to spend a few
hours up on the roof to attend to the system.
Sky Green towers currently produce three vegetables popular with locals - nai
bai, xiao bai cai and Chinese cabbage, which can be harvested every 28 days.
They already supply NTUC FairPrice, Singapore's largest grocery retailer that
has a network of over 230 outlets and supermarkets. The urban-grown vegetables
cost roughly 20 cents more per kilogram than the imported varieties.
The group's purchasing manager, Tng Ah Yiam, recently told a Straits Times
reporter that these "sky farms" are now able to offer their customers
quality, locally-grown vegetables "that are fresher because they travel a
shorter distance from farm to shelf".
Sky Green plans to supply two tons a day to NTUC by the middle of next year
when they expand their farm towers.
The Sky Green project feeds into a trend that has been underway in Singapore
for several decades.
Since the urban expansion of the 1990s Singapore has attempted to respond to
the scarcity of land available for traditional cultivation by promoting rooftop
A number of local institutions developed hydroponic and aeroponic cultivation
systems but none ever took off. "There was always concern over whether or
not the rooftops could take the weight of these structures," Shih Yong
Goh, former head of public affairs at AVA, told IPS.
Experts like Lee Sing Kong, director of the National Institute of Education and
a long-time advocate of the use of 'sky farms', believe there is an urgent need
for Singapore to become less dependent on food imports.
Given the increasing frequency of extreme weather events, including
"natural disasters such as flooding, which could impact food production,
it may be necessary for Singapore to look at producing some of its own
vegetables from the food security point of view", he told IPS.
Kong said that he is currently involved in the development of 'vegetable
factories', whole buildings designed to grow fresh produce.
"We have (begun) developing a six-tiered aeroponic system to grow
vegetables with the help of LED lights," he said, adding, "this is in
the experimental stage. If the model proves to be successful, then the
multi-tiered system can be installed within enclosed buildings for producing
vegetables. This will certainly enhance the opportunities for urban
Since 2005, the government has shed some of its reservations about rooftop
production. The National Parks Board recently converted the rooftop of a
multi-story residential building in the densely populated Upper Serangoon Road
into an educational farm to promote urban agriculture among school children.
Meanwhile, Sky Green has signed an MOU with Singapore's Temasek Polytechnic
technical college. Dr Lee Chee Wee, director of the School of Applied Science,
believes that partnering with Sky Green will expose his students to how
technology is used in vegetable farming and make "modern farming so much
more attractive as a career choice for our graduates".
By Kalinga Seneviratne
The article can be viewed here
(Inter Press Service)
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Source: Asia Times, Hong Kong (Online)