By Qingwu (William) Meng
When I returned to Michigan State University (MSU) for my PhD 2.5 years ago, I was beyond excited to be involved in the development of a brand new research facility, the Controlled-Environment Lighting Laboratory (CELL), led by my advisor, Dr. Erik Runkle. The idea behind it was to create a dedicated space for not only lighting research on indoor vertical farming, but also teaching and outreach activities. CELL is located conveniently by busy classrooms on the first floor of the Plant & Soil Sciences Building. Its large, bright windows peppering the hallway with all different kinds of lights offer an intriguing view for students and passersby.
OSRAM helped us design, engineer, and build custom LED fixtures with 7 independent color channels (UV-A, blue, green, hyper red, far red, and two whites). These fixtures aren’t the typical ones with constant light outputs, but rather, they are controlled by the proprietary OSRAM Spartan Control Software. The intensity of each color channel at plant canopy can be dialed up or down at 1-µmol intervals. As a result, numerous spectral combinations can be created, scheduled, and tested.
What is now CELL used to be a storage room filled with cabinets and bookshelves. While Erik worked with the MSU Infrastructure Planning and Facilities and technician Steve Brooks to remodel the room, I trialed growing racks with help from Steve and another technician Nate DuRussel and tested the LED fixture prototype from OSRAM. As soon as the flooring, window, door, plumbing, electrical, and HVAC work was completed, I assembled all 8 growing racks with Nate and a couple of undergraduate students and then worked on hydroponic tubing with Steve. After the engineers from OSRAM installed final LED fixtures on the racks, they guided me through various scenarios of interfacing with the fixtures and continued to provide full, generous technical support.
Leafy greens such as lettuce and kale are grown hydroponically in a deep water culture system. Within each of the 8 racks, oxygenated nutrient water circulates in between a reservoir and three vertical layers. This ensures a consistent supply of nutrients to plant root systems while conserving water. Since the passively cooled LED fixtures emit little radiated heat, the distance between them and the plants is shortened to merely 1.5 feet, making it possible to stack growing planes vertically to maximize space use efficiency. I made a video during the first test run of the growing system in April, 2017.
OSRAM also made a neat video in June, 2017 to showcase our research missions in CELL. Light is both an energy source and a signal to plants. Since it mediates photosynthesis and secondary metabolism, it is a powerful tool to increase crop yields and improve nutritional value and taste profiles. Yes, we ate lettuce grown under different lighting conditions and discerned sensory differences.
The test runs allowed me to improve the growing system and methods. My first official experiment spanned from June, 2017 to November, 2017 with three replications. When plants were one month old, I collected data on plant shape, pigmentation, and biomass. Here is a video I produced to document some highlights of this experiment. I plan to present the findings at the American Society for Horticultural Science (ASHS) annual meeting in the summer of 2018.
Engaging in the building process of such a technologically unique and advanced plant lighting lab from the ground up is priceless to me. I feel truly grateful for having this opportunity and learning so much from everyone involved in this project: I acquired practical and technical skills that complement and enrich my scientific learning. I’m excited to conduct more plant lighting research in CELL before I graduate in late 2018 and hope to transform more scientific knowledge into applications that benefit the rapidly evolving vertical farming industry.