Understanding Light for Controlled Environment Agriculture

Dr. Roberto Lopez is no stranger to light management in controlled environment agriculture. In fact, he co-wrote a book on the subject. 1 That book is just one among dozens of publications, honors, and awards he has earned for his contributions to the greenhouse community. He is also an active member of multiple extension groups, including Floriculture Research Alliance, MSU Floriculture and Greenhouse Crop Production Team, and Electronic Growers Resources Online.

For more than 15 years, Dr. Lopez has been researching the effects of light intensity, quality, and photoperiod on greenhouse and indoor production. In 2016, Dr. Lopez returned to the Department of Horticulture at Michigan State University. This time on the educator's side of the lectern. His position at MSU allows Dr. Lopez to impact lives through his research, including those of students and greenhouse growers.

Dr. Lopez’s lab is focused on the effect of supplemental, sole-source, and photoperiodic lighting during propagation and production of young specialty crops, including floriculture, leafy greens, and herbs. 2-5 For instance, Kellie Walters, one of Dr. Lopez’s graduate students, is studying how different light intensities and carbon dioxide can influence the taste of basil.

Implementation of light recipes requires the lab to get detailed measurement of spectra and to modify their lights as necessary. The lab uses adjustable LED fixtures for their increased energy efficiency and improved control over light composition. LI-COR’s LI-180 Spectrometer lets them quickly verify spectral intensity and composition at the plant level.

Using the spectrometer, researchers can make changes to the LED lights, take a measurement, and see how their changes have affected spectral conditions, all within seconds. “[Other instruments] were time consuming and difficult to use. You had to have a laptop and software system to see your measurements – it’s a lot of interface time,” Annika Kohler, another of Dr. Lopez’s graduate students, said. “The LI-180 made it easy to figure out what I wanted with the lights. It’s really user friendly.”

The research Dr. Lopez and his lab are conducting can provide growers with a framework to reduce energy costs while improving quality and yield. This is vital research for the continued growth and support of Michigan’s large greenhouse industry and greenhouse growers everywhere. Researchers and students who continue to make new discoveries and foster relationships in the grower community are seeds for the advancement of science and the growth of controlled environment agriculture.