Published by City Farmer, Canada's Office of Urban Agriculture


Singapore's Aero-Green Pioneers Tropical Aeroponics

An Agrovision Publishing Report
Geoff Wilson,
Executive Officer (honorary),
The Urban Agriculture Network - Western Pacific Office,
PO Box 85, Mt Gravatt Central,
Queensland 4122, Australia.
Phone 61 7 3349 1422
Fax: 61 3343 8287
Mobile: 0412 622 779

Aeroponics has long been tipped as one of the most appropriate hydroponic technologies for urban agriculturre and microfarming in warm climates.

But until Singaporean and Malaysian business interests combined to form the Aero-Green company operating in Singapore, the technology has not been used greatly by either commercial interests or microfarming hobbyists.

Aero-Green Technology (Singapore) Pte Ltd., a S$12 million company on 5.7 hectares, is fast changing that, and is actively promoting aeroponics both to its local customers, and to any group that cares to visit.

Aero-Green had its genesis in development work in tropical aeroponics by Singapore's National institute of Education, Nanyang Technological University (NTU).

According to Professor Lee Kong Sing of NTU, on whose work the company was based, the project is the first of what could be many others in aeroponics -- both commercial and hobby -- in Singapore's six agrotechnology parks and on rooftop microfarms on both commercial buildings and apartments.

Singapore's developments on both kinds of sites over the next five to 10 years are expected to startle the world.

Aero-Green is also trend-setting in what a hydroponic farm can be in terms of both tourism and community education.

It's basic module of production, a wheeled structure, is a concept that could easily be marketed as a stand-alone unit for microfarming in the tropics and sub-tropics.

Aero-Green is a company capable of such marketing. It is mostly owned by the multi-faceted Malaysian conglomerate named Sime Darby (see separate story), but with significant investment interests by far-sighted Singaporeans.

Aeroponic farming practised by Aero-Green uses welded-pipe structures on wheels, so that they can be pushed together and only opened out for planting, harvesting and cleaning before the next planting.

Such a wheeled structure (albeit with larger wheels on castors), could be well used on rooftops, food decks and on concrete aprons -- then be wheeled indoors when protection from the weather is advisable.

The light-weight structure pipes hold plastic sides and a bottom in a kind of tank from which sprays provide a mist of nutrient solution to seven types of lettuce plants on polystyrene trays. It is a simple recirculating system fed from a nutrient tank, to which the nutrient is returned. A big advantage is that the misting cools the nutrient.

Another is that the nutrient can be cooled before use, if necessary. When the growing cycle is complete at Aero Green, after three to four weeks, the trays of lettuce are carried to an automatic harvester, to be packaged for sale.

On the other hand, a hobbyist microfarm based on the structure could have a nutrient storage tank and pump unit under the misting sprays, so that it is self-contained.

The company's greenhouses have fine screens to keep out pests, so that produce can be marketed as "pesticide free". A hobbyist aeroponics unit could have the same advantage if the structure above the plants is meshed over with mosquito netting.

Indeed, students and the general public can see this for themselves during the morning, lunchtime and afternoon visit program that is and important part of the Aero-Green marketing strategy.

Features of this strategy include:

Whereas many hydroponic companies tend to be secretive about their technology, Aero-Green is very open about most of it, no doubt because the company's real secrets of business success in innovative hydroponics are recognised as lying in good management. I expect the company to have another good future in marketing stand-alone aeroponic units for microfarming.

Sime Darby is a big player

Established in 1910 by a Scot, William Sime, and an Englishman, Henry Darby, the Sime Darby company has grown into one of Southeast Asia's leading conglomerates. It is based in Kuala Lumpur in Malaysia, when Sime Darby Berhad became a Malaysian company in 1979. It has a market capitalisation of more than US$1.5 billion, and gross assets worth nearly US$3 billion. Besides having extensive holdings in Malaysia, Singapore, Hong Kong and Australia, Sime Darby operates 12 other countries of the Pacific Rim, and in the United Kingdom, Egypt and South Africa. It has more than 300 subsidiaries in 23 countries, and employs 38,000 people. While the company's original interests were mainly in oil palm plantations, its business now covers a wide range of agribusiness interests, plus motor vehicle and equipment marketing interestes. Sime Darby's Singapore interest in tropical aeroponics can thus be counted as most likely to be significant for the technology's long-term future in the tropics.

Aeroponics is ideal for rooftops

One of the most interesting concepts mooted for Singapore is rooftop gardening and farming using aeroponics.

Professor Lee Sing Kong, the academic who has led Singapore's aeroponic development, is a long-term advocate of better use of rooftops through plant growing for aesthetics, better energy conservation and improved food production.

The aeroponic technology has significant advantages in reduced weight for rooftops, plus greater versatility for vertical or sloping walls of buildings that face the sun.

Professor Lee has also been advocating aeroponics as a superior technology for vegetatively propagating plants, including forest trees. Since the 1980s Singapore has had an enlightened "Garden City program" of planting trees, shrubs and flowers along roads, and in public spaces.

More recently its planners have turned to doing something about horizontal rooftops and the vertical faces of its high-rise buildings. For example, in the Singapore Institute of Architects proposal for the Kampong Bugis Development Guide Plan, released in October 1990, it was proposed that 100% of all horizontal surfaces, and 60% of all vertical surfaces should be planted -- with aeroponics being the dominant technology.

Professor Lee said: "This is aimed at creating a unique feature of Singapore to further enhance the image of the island as a tropical garden city."

He expects Singapore unique aeroponic building design to serve as an effective model for other cities in the tropics.

Agrotechnology parks ideal model for urban agriculture

Singapore's six agrotechnology parks are located on the last 1,500 hectares of this island-state's agricultural land (down from 25,000 hectares a score or so years ago, before a building boom for commercial enterprises and housing.

The 1,500 hectares represents about 2.5% of Singapore's land area. It has about 150 hectares of sea space reserved for salt-water aquaculture. The six agrotechnology parks produce fresh food from intensive industries in hydroponics, aquaculture, poultry for eggs and meat, and aquaculture -- within kilometres of where it is consumed. This is one of urban agriculture's greatest appeals.

The Singapore development is thus becoming a beacon for people interested in urban development that saves transport energy cost of food (which can often be more than 50% of total cost to the consumer). Four different hydroponic technologies are practised by a range of farmers in the agrotechnology parks. The simplest form is a drip-to-waste system using plastic bags filled with crushed rock (see cover photo).

Less simple is organic hydroponics using a substrate of charcoal in pots and a nutrient fermented from soy flour and molasses. A Gericke-style system of floating polystyrene rafts on a deepish bed of moving nutrient is common, while the oval channel system of Australian tropical hydroponics pioneer, Des Boxsell, is also used.

Aeroponics is the other system well-suited to Singapore, a country very close to the equator, where nutrient-film technology has problems of ambient temperature take up.

The Singapore Government's Primary Production Department is a strong supporter of the development of hydroponic ventures in the six parks, and has helped a number of former pig producers to change from animal production to more benign plant production.

Intensive pig production in Singapore was banned more than 10 years ago, mostly because the city-state foresaw its need to allocate space to less polluting food production industries such as those based on hydroponics.

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Revised Thursday, February 10, 2000

Published by City Farmer
Canada's Office of Urban Agriculture