NY Times: Tenderizing the Tundra With Some Light and Heat"

The New York Times has this great look at the heating system that keeps Lambeau Field's turf in great shape throughout Wisconsin's winter months:

Tenderizing the Tundra With Some Light and Heat

By JOHN BRANCH
Published: January 13, 2012

The “frozen tundra” is a myth. The ground at Lambeau Field, legendary home of the Green Bay Packers, is heated. It has not been frozen during a football game since it was dubbed the “frozen tundra” more than 40 years ago.

And that impossibly green grass these days, despite the calendar turn to January? Trace it, in large part, to a new system of artificial lighting employed to counter the meek late-autumn sunshine in Wisconsin.

Green Bay’s famed “frozen tundra,” besides being redundant — tundra is, by definition, frozen — is downright tropical, even during the N.F.L. playoffs.

“It’s just like playing in the summer on the grass,” Green Bay offensive lineman T. J. Lang said. “It’s never hard, it’s never frozen.”

When the Giants play the Packers at Lambeau Field on Sunday, they will face more than the team with the league’s best record (15-1). The Giants (10-7) will enter the setting of the league’s most impenetrable mystique. The winter weather in Green Bay has a reputation for ferocity, as much a part of the franchise’s identity as Bart Starr and Brett Favre.

The images are etched: fans bundled in layers, players removing helmets and releasing steam that rises from their heads, Giants Coach Tom Coughlin with a face so red during the N.F.C. championship game four years ago that some viewers may have adjusted their televisions.

The air at Lambeau Field might occasionally be frigid. But the tundra, hardly tundra at all, is decidedly not.

The ground below Lambeau Field has been heated since 1967, when Coach Vince Lombardi oversaw the installation of electric coils that zig-zagged under the turf like wires in an electric blanket. The aim was to keep the ground soft enough so that cleats could grab hold and players could keep their footing.

For 30 years, those coils kept Lambeau Field soft, with one exception. That came months after installation, when the Packers played host to the Cowboys for the 1967 N.F.L. championship. Temperatures well below zero were too much for the system. The field grew stiff and slick. The game was nicknamed the Ice Bowl. Writers in the aftermath dubbed the playing surface the “frozen tundra.” The term stuck. It remains frozen in time.

The electric coils were replaced in 1997 by a system of pipes filled with a solution including antifreeze. These days, the temperature of the soil is controlled by the field manager Allen Johnson. With temperatures Sunday expected to be in the 20s, Johnson will probably set the soil temperature to about 40 degrees. That will be enough to offset the subfreezing air temperature and keep the field soft.

It is not warm enough, he said with a hearty laugh, to entice players to linger on the grass for an extra moment or two at the end of a play, soaking in the warmth of the ground. Even on the coldest days, players are not likely to feel heat rising from beneath their toes.

While heating the soil at Lambeau Field is a concept about as old as the Super Bowl, the artificial lighting system used there is a burgeoning technology, designed by the Dutch firm S.G.L. — Stadium Grow Lighting. The founder of the company, Nico van Vuuren, tweaked a system he built for growing roses. He plans to attend his first N.F.L. game Sunday in Green Bay.

In essence, the system is a complex grid of retractable arms lined with hundreds of greenhouse-type light bulbs. After a trial run in 2010, the Packers bought nine MU360 units, as they are called, enough to cover half the field.

The contraption fools Mother Nature. Johnson used the lights 24 hours a day from October to early December, moving them every other day between games. Because the lights hang about six feet above the grass, other groundskeeping duties — mowing and watering, mostly — can continue, though the blast from a high-pressure sprinkler can occasionally shatter one of the long, clear incandescent bulbs.

Not only did the lights cast a warm and eerie glow from inside Lambeau Field through the night, they extended the growing season for the grass well past the normal date of dormancy.

Johnson said grass needs three vital elements to grow well: warm soil (check, thanks to Mr. Lombardi), good light (check, thanks to Mr. van Vuuren) and warm air (hmmm). By mid-December, when daytime temperatures rarely rise above freezing in Green Bay, the lights and warm soil are not enough to offset the frigid air. But the results linger.

“The payoff and the benefit is now,” Johnson said. “We have a more full canopy and more grass than we would without it. The green color is a side benefit. That’s aesthetic. The main benefit is stronger, healthier grass, thicker grass in places where it’s usually difficult to grow.”

The system was not in place at Lambeau Field in 1967 when the Packers played the Cowboys in the Ice Bowl. The low temperatures overwhelmed the system used to warm the ground.

S.G.L., which does much of its business on European soccer fields, is just now making inroads in North America. Many soccer stadiums are built like boxes, a field surrounded by steep stands and a partial roof to help shield fans from rain. Some fields, or parts of them, get little or no sun.

The New York Red Bulls purchased three of the units for their soccer-specific stadium in Harrison, N.J. The southern end of the stadium rarely gets sunlight most of the season, which extends from March to November, and the penalty box area — a high-traffic, critical area of the field in front of the goal — required new sod several times before this past year.

“The year before, it was definitely brown and it didn’t look right,” said Dan Shemesh, director of grounds for the Red Bulls. “You could always tell the south end: the air was colder, the soil was colder, the grass was thinner. It didn’t need to be mowed much.”

That changed in 2011, thanks to 24 hours a day of artificial sunlight provided by 1,000-watt bulbs, used mostly in the spring and fall.

“This past year, actually, that end was better than the other end,” Shemesh said.

Other North American franchises have expressed interest in the systems, particularly Major League Baseball teams that play in stadiums with retractable roofs. The Houston Astros have joined the Packers and the Red Bulls as the only professional American franchises to use the system.

The Packers, mostly fighting the cold and a short growing season, do not have a shade problem. But it is coming. Construction of new bleachers has begun on the south side, now the open end of the stadium, which promises to block sunlight in a couple of years.

“Getting lights was our answer to combat that,” Johnson said.

For teams like the Giants, there are plenty of things to combat during a January visit to Green Bay: quarterback Aaron Rodgers, linebacker Clay Matthews, the likelihood of cold weather and an energized crowd among them.

The notion of the frozen tundra, despite the constant reminders, is one thing they can try to forget.

A reminder that it's not just the Packers' green uniforms that look good throughout the season....