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Sky Greens’ vertical farm


The wealthy island city of Singapore with an area of 710 square km and a population of 5 million, is one of the most densely populated cities in the world. With most parts of the island’s land utilized for urban development, the remaining 250 acres of farmland is hardly sufficient to feed the growing population. As a consequence, more than 90 percent of Singapore’s food consumption is met by imports from over 30 countries. This dependency on the external world makes the country highly vulnerable to turbulence in food supply and prices.

The only way out of this problem is to maximize the use of land for food production. For the island of Singapore, where real estate is at a premium and the land rates are exceptionally high, the only viable option is to go vertical to make the island more self-sufficient in food.

Image Courtesy MNDSingapore

In making this goal of a food self-reliant Singapore a reality, Entrepreneur Jack Ng, with the help of Agri-Food and Veterinary Authority (AVA), has come up with one of the world’s first commercial vertical farms. This soil based vertical farm produces one ton of vegetables every other day and is five to ten times more productive than a regular farm.

Jack Ng, Managing Director of DJ Engineering, has set up a company, Sky Greens, to produce the vegetables commercially and sell the technology to other countries. The father of two children, who dropped out of school after Secondary 4, came up with this idea during the financial crunch in 2009. Ng adds, ”Food prices were going up because of supply disruptions overseas, so I had the idea of growing more food here”. It took him two years to develop the idea.

“A-Go-Gro” Technology

It is the first low carbon hydraulic water-driven vertical system in the world to grow tropical-vegetables vertically in the tropics, which gives significant yield and uses less water, energy and natural resources, to achieve a sustainable green high-tech farm.

Image Courtesy MNDSingapore

This vertical farming system, called “A-Go-Gro” technology, grows vegetables in A-shaped towers, each of six meters tall. These modular A-frames are quick to install and easy to maintain. Each tower consists of 22 to 26 tiers of growing troughs, which are rotated around the aluminium tower frame at a rate of 1mm per second to ensure uniform distribution of sunlight, good air flow and irrigation for all the plants. As Ng points out, “The plants don’t get overstressed under the sun… at the same time they can get nutrients in the water equally “.

Image courtesy Sky Greens

The rotation system does not need an electrical generator. It is powered by a unique gravity aided water-pulley system that uses only one litre of water, which is collected in a rainwater fed overhead reservoir. This method also boasts a very low carbon footprint as the energy needed to power one A-frame is the equivalent of illuminating just one 60-watt light bulb. The water powering the frames is recycled and filtered before returning to the plants. All organic waste on the farm is composted and reused.

Image courtesy MND Singapore

The vertical farming system is housed in a protected environment of PVC roofing and netted walls to enable cultivation of tropical leafy vegetables under natural sunlight, all year round. All these efficiencies ensure that production costs are kept low. Operational costs include raw materials like soil and seed and electricity to pump the water driving the structures. But electricity costs come to only $3.00 per month per structure.

Image Courtesy MND Singapore

This farming system generates significantly higher yields than traditional growing methods — they are safe, of high qualify, fresh and delicious. Large varieties of tropical vegetables are grown, such as, chinese cabbage, spinach, lettuce, xia bai cai, bayam, kang kong, cai xin, gai lan, nai bai, etc. As the farm expands, Sky Greens intends to grow more vegetables.

Image Courtesy MND Singapore

The whole system has a footprint of only about 60 square feet, or the size of an average bathroom. A total of 120 such towers have been erected in Kranji, 14 miles from Singapore’s central business district, with plans for 300 more, which would allow the farm to produce two tons of vegetables per day. Ng wants to build over 2,000 towers in the next few years. He also has plans to sell this technology to other countries with a price tag of $10,000 for each tower.

Image Courtesy MND Singapore

Sky Greens’ venture is supported by the Singaporean government and has another advantage over other urban farms around the world: abundant natural heating and light. Singapore has year-round temperatures of around 86 degrees Fahrenheit (30 degrees Celsius) and the farm is set in an open area designated by the government as an agro-technology park, miles away from the shadow of city skyscrapers.

Positive outcome

Sky Greens stringently adopts green technologies to achieve the 3R (reduce, reuse and recycle). This also helps to achieve sustainability for the good of the environment and to grow safe, high quality and fresh vegetables for consumers. The small amount of energy and water needed to grow vegetables, and the close proximity of the consumer potentially reduces transportation costs, carbon dioxide emissions and risk of spoilage.

Image Courtesy MND Singapore

The vegetables are harvested everyday and delivered almost immediately to retail outlets. Although Skygreens’ vegetables cost about ten percent more than the imported vegetables, they are literally flying of the selves with consumers happy to buy Singapore-grown produce. As one of the consumer mentions, ”The prices are still reasonable and the vegetables are very fresh and very crispy.”


Every day vegetables are shipped into Singapore from neighboring countries like Malaysia, Indonesia, and from far off countries such as China, US and countries from Europe. The Singapore government, in order to cut down on this dependency, has an objective of reaching 10 percent local production of leafy vegetables. The current figure stands at 7 percent. This initiative of vertical farming along with the existing 37 vegetable farms, will definitely help to reach the 10 percent local production target. This will not only reduce the “food miles” but also mitigate supply shortages and hoarding. As one government official puts it, “We cannot depand totally on imports. We are a land scarce country and therefore need to be able to maximise use of our land in the area of food production. Local production acts as a buffer against severe disruptions in food supply “.

The concept of vertical farming has been on the design table for a long time. Big think tanks have thought about it, conceptualized it, designed it, have gone through all the advantages and disadvantages, but none have been able to bring it into reality. Until now, implementing these “farmscrapers” on a commercial scale has been a challenge and making them economically viable has been a daunting task. Requirements such as, pollination in an insect-free environment, controlling the environment within the buildings with regards to lighting, temperature, arrangement of plants, etc, make food production in a vertical farm a very expensive affair.

It’s still up for debate whether vertical farms are more efficient at producing food than traditional greenhouses. As Gene Giacomelli, a plant scientist at the University of Arizona points out, “The limiting factor is light. The total food produced depends on the amount of light reaching plants. Although vertical farms can hold more plants, they still receive just about the same quantity of sunlight as horizontal greenhouses. The plants have to share the existing light, and they just grow more slowly. You can’t amplify the sun”.

Sky Greens’ vertical farm seems to answer some of these doubts and apprehensions. It still needs to be seen whether, apart from leafy vegetables, they can also grow other vegetables, such as tomato, beans, potato, carrot, etc., or commercial crops like rice, wheat, etc., economically.

Further Reading:

13 Responses to “Vertical Farming: Singapore’s Solution to Feed the Local Urban Population”

  1. Michelle

    Congratulations Mr Ng for your vision, a great solution to a growing world wide problem where food production is under threat & we must now work hard to protect our supplies of seeds.

  2. Dr. Richard

    One of the critical design factors for vertical farms is to match the farm’s energy usage with on-site renewable energy generation for both heat and electricity. This is particularly true for vertical farms which make heavy use of LED grow lights.

    There are a lot of fanciful high-rise vertical farm designs for urban areas — all of which have a fundamental design flaw — their energy requirements exceed what is feasible either generated onsite or even available from most urban electric grids. Some of these idiotic designs would literally require 50 to 100 megawatts of industrial three phase power and would need hundreds of millions of dollars to build with dubious economic returns. However, the concept is viable in shorter (e.g. 15′ to 30′ high) structures attached to commercial scale greenhouses (1-10+ acres in total greenhouse space) with 7-20+ acres of utility scale solar.

    Sky Green has excellent solar resources and doesn’t need heating given their tropical location near the equator. However, they do have significant pumping, motor, and air conditioning loads.

    Expect to see exponential growth in the coming years for vertical farms. Cheap utility scale solar has made indoor vertical farms economically viable. The major Japanese electronics firms (Fujitsu, Panasonic, Toshiba, & Sharp) have all made major investments in LED / Solar powered indoor vertical farms in the last two years. The number of these farms in Japan has gone from zero three years ago to over 380 today according to a recent article in the Wall Street Journal.

  3. Dylan

    Interesting.. although wondering where the soil comes from? how often is it replaced? Is it closed to the environment i.e. no pests coming to eat the veggies? (no pesticide use?) and how many chemicals are added to the water? i.e. if this is chemical farming in another guise? perhaps these factors should be included in the article before the word sustainable is used

    • Dr. Richard

      These are all some variation of aquaponics or hydroponics. Most use soil-less cultures – usually rafts, rockwool, gravel, sand, coco coir, etc. The processes can be organic or can be non-organic with lot’s of chemistry added in the nutrient solutions. The environments are all controlled so pests are eliminated along with the need for pesticides.

  4. keveen

    I always admire such initiatives but somehow, I can’t help but think that food grown in the soil, connected to the earth is far more important. Whomever uses the earth (at least with healthy practices) will inevitably take care of the land, and improve the ecosystem. I prefer smaller outdoor gardens (even on roofs) than sterile-looking environment.

    • Craig Mackintosh PRI Editor

      If this was hydroponics-based, I wouldn’t have put it up. But this one was interesting, as the plants are grown in soil – not on chemical-infused sponges.

      Yes, having roots in the ground is always going to be best, but considering Singapore’s highly vulnerable situation, if it wants to be at least a little more self-sufficient with the extremely limited land-base it has, some compromises will have to be made.

      And, do consider that this is an idea that can be examined and improved upon also.

  5. S.Sriram

    Excellent. The idea is highly impressive and my congratulations for Mr.Ng for the initiative. We are assisting in establishing organic vegetable and fruit garden and this idea can definitely make a change.

  6. Caleb

    Has there been any thought to using vertical floating pillars for growing food? Round floats to support the weight of each pillar, each individual pillar slowly rotating while all the pillars are rotated around a oval tank. A small electric motor would be enough to run the top mounted drive chain, space each pillar so as to allow sunlight through to the backside of the unit. Every plant would spend minimal time the shade (if desired), rather than only 2 hours of sunlight per row. I haven’t looked into this method, so actual engineering and cost could prove to be prohibitive, just a thought that has been kicking around my head.

  7. GCMREddy

    its good and I would like to go for similar one in my land in 666Sq yards at Hyderabad India. Hence I request you to give me details .

  8. Douglas Jack

    Trees are very efficient vertical farms which produce abundant greens (eg. spruce buds in the spring are delicious & nutritious), nuts (protein & starch, seeds, sap & fruit. Trees create, maintain & maximize their own vertical structures. ‘Indigenous’ (Latin ‘self-generating’) 3-dimensional Polyculture Orchards PO photosynthesize 92 – 98% of solar energy converted into food, materials, energy & water-cycle. Typical 2-D ‘agriculture’ (L ‘ager’ = ‘field only photosynthesizes 2 – 8% of solar energy. Tree roots descend 10s of metres, as deep as the canopy pumping water, mining minerals & developing deep nutrient colonies to serve the whole food infrastructure all solar powered. Ag roots descend only centimetres. PO calm winds, root soil (no wash away), act as heat pumps, mitigate earthquakes, store toxins for a lifetime (~1000 years), provide climbing structure for food vines (eg. grapes) and create habitat for all species above & below. All species enhance production. With these & other efficiencies PO are 100 times (10,000%) more productive than agriculture.

  9. Dilip Pendse

    If bio dynamic500, organic Silica and fertigation thru hydroponics incorporated, the yields will multiply


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