Fresh vegetables in the heart of the city

Air filter for high-tech farming, Singapore

FanGrid in Changi Airport

©Artisan Green

Artisan Green grows leafy vegetables in the middle of Singapore. In the company’s vertical gardening farm, it is growing spinach and other leafy vegetables under controlled conditions. A special air filter with EC fan produces the ideal climate for the young green plants.

Those who visit Jaime Tan at his place of work can’t believe what they see. Tan works for Artisan Green and the company cultivates spinach, baby kale, and herbs. However, you will not find any fields here. Instead, the General Manager’s desk is located on the fourth floor of a commercial building in Singapore. Growing vegetables in the middle of the city? Jaime Tan laughs and explains, “We specialize in hydroponics. The roots of our plants are not in the ground but are suspended in a nutrient solution, which contains a mixture of water and dissolved nutrients. They grow in plant racks instead of on farmland.”

This is also one of the major advantages of vertical gardening: it saves a lot of space. This means that the method fits perfectly into the densely populated metropolis Singapore and with the “30 by 30” program. With this initiative, the government of the city state intends to cover around a third of the food demand with local food products by 2030. With the motto “from lab to table,” it subsidizes innovative ideas. Ideas such as the business model of Artisan Green, which was launched in 2018.

Ventilation for vertical farming staff spinach

A staff member of Artisan Green checks the growth of his green protégés in the vertical gardening farm in Singapore. (Photo: Artisan Green)

Less is more

Jaime Tan explains: “Our farm is a laboratory where we can try out how we can optimize production. It is still not about large quantities.” Artisan Green is still growing: initially, the team harvested around eight kilograms of baby spinach per week, now it is harvesting as much as 60 to 70 kilograms. In addition, the area available for growing products has been expanded from 10 to 60 percent. The product range has also grown: in addition to spinach, it is now also growing red baby kale, dill and cilantro. Basil, thyme and sage are to follow.

You can buy the leafy vegetables in various supermarkets in Singapore. “At the beginning, some customers were critical and thought that many chemicals would be used for indoor planting. The opposite is the case. The plants are protected from pests, so we do not need pesticides.” And they also live up to outdoor varieties in terms of taste. Hydroponics also saves water: the nutrient solution is filtered and then reused. In other words, it is a closed cycle.

A sensitive matter

Before Jaime Tan leads visitors through production, they all have to put on protective clothing. If germs or impurities get into the closed space, it can impair growth or even destroy the entire harvest. “The system is very sensitive. Even slight fluctuations in temperature, humidity, pH value or the nutrient mixture have a direct impact on the growth of the plants,” explains Tan and points to the metal racks where their delicate baby spinach and red baby kale are sprouting, under artificial light and in optimum conditions. The team researched these conditions over the past year. “We already know a lot but are getting to know our plants and their needs better and better,” says Tan.

Tiny spoilsports

Particular attention is paid to the air quality in the farm. After all, this is what largely decides whether spinach and other leafy vegetables will grow as they should. Volatile organic compounds (VOCs), such as hydrocarbons, alcohols and organic acids, play a critical role here. The particles are a few micrometers in size and are always present in indoor air. If their concentration is too high, they can influence plant growth and the maturing process. A mobile air filter regulates the VOC levels.

"The system is very sensitive. Even slight fluctuations in temperature or humidity have a direct impact on plant growth." - Jaime Tan, General Manager at Artisan Green

Good air for fresh vegetables

Ventilation for vertical farming air filter

The RadiCal can hack it: the mobile air filter required a high performance in a small space. (Photo: Artisan Green)

Jaime Tan walks over to the 500 by 920 millimeter metal cube on rollers located in one of the aisles. “We developed the device specially for this task. We use an activated carbon filter through which a fan blows the ambient air. Our filter supplier recommended ebm‑papst,” recalls Tan. All parties involved worked closely together when developing and designing the filter unit.

Senior design and application engineer Mr. Hiew Chung Ka from ebm‑papst in Singapore visited Artisan Green and recommended a RadiCal EC centrifugal fan with a diameter of 280 millimeters. “The air filter unit must fit into the narrow aisles, so there is limited space. With its compact design and high performance, the RadiCal was a perfect fit,” he recalls. “Together with Jaime Tan and his development team, we looked at how much space we needed around the fan. This resulted in an optimum aerodynamic design for the air filter unit.”

The fan is currently running at 50 percent of its maximum speed, which is sufficient for the current growing space. If the farm expands, the speed can be increased. Tan and his team noticed immediately after it was first used, “It is very quiet! Our air filter is an important but also inconspicuous element in our farm.” He adds with a laugh, “We have not had to do anything for it since it arrived. It is doing its job!” It is not only Jaime Tan who is pleased: the plants are also thriving on their shelves.