At full capacity, when the energy cost is neglected, it can produce 1,000 tons of leafy greens a year in theory, according to Li. "The high productivity is mainly because we try to emulate the most ideal natural conditions for plant growth, and use technologies to cater to their every needs."
Before entering the plant factory, visitors must put on a dual-layered jumpsuit, goggles, a face mask, rubber gloves and boots, and be disinfected from head to toe. Sneezing in the factory is strictly prohibited.
"The standard here is stricter than hospital operating rooms," said Zheng Yanhai, a botany researcher at the institute who works at the plant factory. "Because all the plants are growing in nutrient-filled hydroponic solutions, we do not want germs to get into the liquid and make plants sick."
Thanks to the clean environment, plants can grow without antiseptics or pesticides, "you can even eat it fresh out of the bag", Zheng added.
In addition to sanitation, scientists also take temperature, humidity, air circulation, light, carbon dioxide, nutrients and other elements into account to create the "perfect environment" for growth.
A tightly controlled environment not only maximizes growth potential, but also allows scientists to create food that suits specific needs, Zheng said.
For example, scientists can lower the amount of potassium from lettuce for patients with kidney problems or increase zinc in cabbage for children by altering the nutrient solution and growing conditions.
"This is the fundamental difference between a plant factory and conventional farm," he said. "We simply have extensive control over how and when our plants can grow, and let nature run its course in the most ideal conditions."
The requirements for plant growth fall into two broad categories: photosynthesis and soil nutrients.
The sun accounts for 90 percent of all botanic bioenergy through photosynthesis — a process in which plants combine carbon dioxide and water and turn them into carbohydrates and oxygen. Sunlight is a bundle of different wavelengths of light across a wide spectrum from ultraviolet to infrared.
Plants are "picky eaters that favor blue and red lights", Li said. "If we can figure out what ratio and combination of lights are best suited for each plant's growth, then we can change or create LED lights that shine at that specific intensity and spectrum, saving lots of energy in the process," he added.
While blue and red lights are the "meat and potatoes" of a plant's growth, scientists notice other spectrums of light also play a subtle role in maximizing growth and quality.
For example, scientists discovered that adding some green light to the red-blue recipe could help some vegetables grow, while too much green light puts plants into hibernation, although this is helpful for the plant's nutrient build up.
"Mimicking sunlight using LED is very energy intensive," Li said. "At the end of the day, whoever has the most energy-efficient and productive light recipe wins."
