SEOUL, Nov. 1 (UPI) -- For the past month, commuters at Seoul's Sangdo subway station have been met with a surprising sight: a fully functioning farm growing leafy lettuce, sprouts and microgreens.
This underground farm doesn't rely on soil and sunlight but uses special LED lighting, hydroponic growing trays and a smart network that controls factors such as temperature, humidity, CO2 levels and light intensity.
The project is called Metro Farm, and the Sangdo location is the first of five subway farms slated to open by the end of the year in a partnership between the Seoul Metropolitan Government and Farm8, a South Korean agriculture company.
The Sangdo farm opened in late October, and a second branch recently opened in Dapsimni Station.
The farms highlight the changing face of agriculture in rapidly urbanizing societies, said Kim Sung-un, senior manager of Farm8.
"As South Korea is aging and the rural population is rapidly shrinking, this is the future direction of farming," he said. "These farms use less space and take less time to grow vegetables."
The operation in Sangdo certainly looks like something from the future, more space station than subway station.
Lettuce is grown on vertical shelves in the main facility, a brightly lit glass-encased 4,240-square-foot)clean room that must be entered through an airlock. The Sangdo farm produces around 66 pounds of greens per day, with seeding and harvesting the only human interaction necessary.
Growing times are reduced in this hydroponic system, taking around 38 days to grow lettuce from seed to harvesting, as opposed to more than 50 days in soil. The farm also absorbs CO2 and pumps out oxygen, contributing to the air quality in the subway station.
A smaller space nearby contains a fully automated robot farm that grows sprouts and microgreens, while a Farm Café sells salads made from the plants at the Metro Farm. The station also hosts an experience center that offers tours and interactive demonstrations of the farm to families and schools.
Kim said that only three employees are needed to maintain the farms across all five subway locations, and these positions are being filled by retirees and disabled workers.
"The best thing about urban farming is that it can improve the lives of people who are socially excluded," Kim said.
The benefits of the subway farm for Seoul are widespread, said Choen So-young, who heads the Smart Farm initiative in the city government, ranging from minimizing transportation to providing a stable food supply.
"As the vegetables produced in the stations can be distributed right away, we can minimize the cost of distribution and logistics," she said. "And the farms are located in urban areas so we can have an easy supply of manpower. In addition, as the smart farms are not affected by the climate change including fine dust, they can have a stable production to supply clean and safe vegetables."
While interest in vertical and urban farming has been on the rise in cities around the world, questions remain about its economic viability on a broad scale. One study in Japan last year found that 60 percent of indoor farm operators are unprofitable because of the cost of electricity to run their facilities.
However, South Korea, with limited available land, extreme seasons that make growing year-round difficult and electricity prices that are among the lowest in the world among developed nations, could prove an ideal urban farm market.
"Compared to the traditional outdoor farming, the vertical type of smart farming can maximize the production volume per unit area throughout the year with a stable condition," Choen said. "So the cost efficiency is the strongest point."
What is certain is that the coming decades are going to require radical new approaches to feeding the world.
A United Nations report from 2013 predicted that the world will need to sustainably produce 70 percent more food by the year 2050 to feed a population of nearly 10 billion. And an August report from the U.N.'s Intergovernmental Panel on Climate Change warned that arable land, which has been declining globally for decades, is under critical pressure from climate change and human development.
In the meantime, commuters at Sangdo Station are getting a taste of the future.
Kim Jie-eun, a 30-year-old teacher, said she lived nearby and was intrigued by the new addition.
"I come through the station often and I noticed the farm," she said while eating a salad from the Farm Café with a friend.
"It was the first time I had ever seen something like this and I wanted to try it, especially because I eat a lot of salads. I like the fact that it's really fresh. And the idea is really new, innovative and creative. I hope more residents will try it."