LEDs light up commercial plant growing

From Nikkei Asian Review,

March 1, 2015 1:00 pm JST

LEDs light up commercial plant growing

KOSUKE TOSHI, Nikkei staff writer

Using reflectors around its LEDs, Nippon Valqua can make plants bloom without natural light.

TOKYO -- Commercial plant growers are increasingly using advanced light-emitting diode technology to help boost the efficiency of their operations. Nippon Valqua Industries, for instance, has developed a product that enhances illumination intensity using reflectors placed around LED chips. Showa Denko's system speeds up plant growth by periodically shifting wavelength. By applying technology to improve crops, these firms are also promoting their own designs for indoor plant-growth facilities.

     Nippon Valqua's plant-growth facility drew attention at Lighting Japan 2015, a mid-January trade show at Tokyo Big Sight. Inside the compact, desktop unit colorful flowers bloomed with the help of the company's hybrid LED.

     The equipment uses reflectors to enhance light density by focusing the light from the LED chips. It draws 18 watts of power, about the same as a regular LED array, but with more than twice the intensity. This sort of plant-growth facility is generally used in producing leaf greens like lettuce. Weak light leaves plant stalks thin and makes blooming difficult. But the reflectors solve that problem, increasing the potential of such facilities for commercial use.

     Nippon Valqua sees its primary customers for the technology among home-improvement and do-it-yourself stores, which face the difficulty of handling seedlings. "We often have to discard the seedlings of flowering plants, as they wither when outside temperatures drop suddenly in early spring," said an official at a leading DIY store. The company says that in times of bad weather and low temperatures, an indoor shelf equipped with hybrid LED lighting can maintain the quality of seedlings for three or four weeks.

     Yano Research Institute estimates the domestic market for plant-growth facilities that depend solely on artificial light at 13.1 billion yen ($109 million) in 2015, more than tripling by 2025 to 44.3 billion yen based on increasing production of medicinal plants and those with pharmaceutical components, as well as nutrient-enhanced vegetables.

     Showa Denko's targets sales related to plant-growth facilities at 5 billion yen in 2016. Its core technology is the Shigyo method, which it developed in partnership with Yamaguchi University. This alternates the wavelength of its LED light, between red and blue at intervals of 12 hours, promoting photosynthesis with the red and plant shape with the blue.

     Under the system leaf lettuce grows to harvestable size in 32 days, 10 days less than systems using only fluorescent light and four days less than with regular LEDs. Seedlings grown under Shigyo-method lighting for 14 days gain weight 2.5 times larger than under fluorescent light. Showa Denko produces plant-growth facilities on order, and plans to deliver about 20 in 2015.