Feature Article - February 2013
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Sports Fields in Context

Making the Right Choices in Synthetic & Natural Turf

By Joseph Bush


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Ken Mrock is in charge of all the fields the National Football League's Chicago Bears play and practice on, both natural and synthetic. He's been with the Bears for 27 years, long enough to see practices and products and equipment come and go or stay, and the advent of artificial turf and the rise of new synthetic science and products.

The latest technology Mrock is fascinated with is artificial lighting to extend grass growing windows. SGL (Stadium Grow Lighting) is a Dutch company that provides a system that includes lighting on wheels so that field managers can pinpoint areas that need extra light. The system also includes computer analysis of grass growth as well as controls for nourishment, water, air, CO2 and temperature.

The NFL's Green Bay Packers, Major league Baseball's Miami Marlins and Major League Soccer's New York Red Bulls have used the system, and Mrock said it could be in the Bears' future.

"It has extended the life of the grass and shortened the recovery time of the grass plant, keeping it very much playable and keeping a good turf cover," he said. "Talking to quite a few people, it seems to be the way we're going. It's not for everybody—it's expensive. You spend the money the way you have to spend it if you want the result."

There's no doubt that an NFL fields supervisor has resources many only dream of. Mrock says the team installed a heated field at their practice facility in the 1990s, and moved that hot water and glycol system to the stadium field in Soldier Field in 2002 to help keep the grass growing as well as help make the surface soft yet firm. There are also field sensors in order to watch moisture and salinity and temperature.

For all that Mrock can buy, he said he will never stray from lessons learned beginning with his days in golf course management. There are certain traits to grass, and tried-and-true methods for maintaining and growing it, that will always guide turf managers regardless of their budget and location.

"It's always going to take a human being to work with Mother Earth," he said. "Some of the old principles are the best. Feeding and irrigation. The same things we do with ourselves. The plant isn't any different. Rest and recovery, just like with athletes, is important for the turf. I always tell people, 'We have athletes out there and they have water breaks to hydrate. The demands are the same.'

"What's even tougher for grass plants is when it gets hotter. The one thing about natural grass, it does come back. It doesn't always look the best, but it does come back. Knowing its limits—how many events or practices or games before it would be a detriment to the health of the plant and to the safety of the participant that's on top of it?

"You want to keep as much cover on the field as possible, by overseeding, or if it needs at some point a re-sodding of an area or a field in order to make sure that it is safe for the participants. You always have to feed the plant just like we have to feed ourselves. It's fairly simple. Knowing what the plant's needs are and giving it the proper nourishment to strengthen it for environmental challenges."

The synthetic field used by the Bears is seven years old. Mrock said both natural turf and synthetic turf have at least one thing in common: They need tender loving care.

"With synthetics you have to groom them and make sure that they're level," he said. "If (the field) gets displaced you want to make sure you get back the integrity and the flatness and cushion. With natural grass there is a lot more work regarding the irrigation, the fertility. Both have to be treated as an ever-changing surface."

Last but not least, especially in a business so often on TV and in the presence of tens of thousands of attendees, Mrock wants his stadium field to look it finest.

"All the seats are pointed at the field," he said. "That's the stage."