Webster’s dictionary defines innovation as “making changes in something established, especially by introducing new methods, ideas or products.”
Innovation is exactly what Nico van Vuuren, a Dutch rose grower and founder of Stadium Grow Lighting (SGL), provided with the introduction of SGL in 2001. The first supplemental turfgrass grow light trial took place in 2003, fittingly at the Stadium of Light in Sunderland, U.K. This complex new introduction of light into stadiums was a simple advancement of the supplemental growth lighting in van Vuuren’s 22 acres of rose-growing greenhouses.
As a core building block for rose growth, light is essential for healthy turfgrass growth, too. With shading from large stadium structures and the sun angle change by the season, consistency of light for grass in a stadium is erratic at best.
Supplemental light units immediately supply the consistency of light needed to sustain healthy, consistent grass growth nearly year round. There is where the innovation comes into play. This “change in something established, especially by introducing new methods, ideas or products” is one of the most dramatic changes to take place in the history of natural grass field maintenance.
The science behind it
Supplemental lighting for turfgrass growth is commonly considered a tool just for natural grass surfaces with extensive shade inside large stadiums.
Yet, in reality, shaded stadiums house only a small fraction of the acres of turfgrass that needs supplemental light.
A 2004 study from Clemson University on TifEagle greens highlights the need for supplemental light, without even calling for it. An August 2004 Golf Course Superintendents Association of America article by B. Todd Bunnell, Ph.D., and Bert McCarty, Ph.D., provides an in-depth look at the study. When tying the research and article content to the need for supplemental light, the article summary says it all: “Without a full day of sunshine, TifEagle bermudagrass greens do not thrive.”
Light can be measured just like any other indicator of distance.
Most horticultural researchers measure instantaneous light in micromoles (μmol) per square meter (m-2) per second (s-1), or: μmolm-2s-1 of PAR (photosynthetically active radiation, which is light with a wavelength between 400 to 700 nanometers; also the light people can perceive). This “quantum” unit quantifies the number of photons (individual particles of energy) used in photosynthesis that fall on a square meter (10.8 square feet) every second. However, this light measurement also is an instantaneous reading.
The study on TifEagle finds that bermudagrass needs a daily light integral of 32.6 mol m-2 d-1. Using light data collection, the city of Atlanta, for example sustains 32.6 mol m-2 d-1 a of light from April until October.
TifEagle then is under light stress and cannot grow efficiently nearly half the year. So why the lack of light?
The limited light is simply due to shorter days and lower sun angle in the sky during the fall, winter and spring season. Dr. Karl Danneberger of The Ohio State University gives a detailed description of the impact that inadequate light has on turfgrass growth in his article “Pour Some Light On Me”: “Turfgrass plants in response to shade or low light levels become more upright in growth habit including thinner, longer leaves, less tillering, shallower rooting and less total root mass. Overall, the turf is subject to a decline in both density and quality. If the winter months are more cloudy and rainy than normal, the detrimental changes would be more dramatic.”
In the South, overseeding with ryegrass into bermudagrass helps offset the decline in bermudagrass quality due to lower light amounts. But dormancy in the bermudagrass is promoted because of a decreased light as ryegrass overseeding blocks light to the bermudagrass. Thus, an overseeded stand of bermudagrass in Atlanta faces even more stress due to inadequate light. That same light stress is equal for nearly all bermudagrass across the U.S., increasing the more north the grass is growing. Light requirement for cool-season grasses is lower, but still their light requirements are equally not met in autumn, winter and spring in Northern regions either.
This type of research and data collection illustrates how grass in shaded stadiums is not the only grass suffering from light stress in need of supplemental light. In fact, data supports nearly that all grass could benefit from supplemental light for extended periods during the year.
The future of light
Since the introduction of supplemental light at Sunderland in 2003, SGL has grown to supply light to over 160 swards of natural grass around the world. And still most all intense light research and innovation is coming from SGL’s lab in the Netherlands.
Originally the interest for supplemental light was with soccer stadiums in Europe. Those stadiums are challenged with maintaining natural grass surfaces through a soccer season that stretches from autumn, through the entire winter season, and into the late spring. Those stadiums face both shade and low sun angle.
Now, with the “growing” understanding that nearly all natural grass surfaces need light, supplemental lighting has spread into the U.S. in the NFL (Lambeau Field), MLB (Miller Park), MLS (Red Bull Arena) and even college sports with the introduction at the University of Tennessee‘s Neyland Stadium. With supplemental light for healthy, consistent turfgrass growth, these stadiums can increase their number of events while reducing maintenance and expensive sod repairs – especially in the autumn, winter and spring seasons.
With the growing demand for high-quality natural grass fields nearly year-round, there is no doubt the number of applications of supplemental light in the sports field industry will continue to grow.