January 9, 2014
From: The Denver Post http://www.denverpost.com/homegarden/ci_24880995/denver-broncos-turf-is-obsessed-about-players
By Susan Clotfelter
You think you've got lawn challenges.
Do you have a nearly thousand-pound equine mascot galloping across your turf to stop on a dime? A couple dozen boot-wearing dancers spinning and kicking on it? Cleat-wearing, millions-earning athletes twisting, charging and crashing on it?
Ross Kurcab has all of that. And multiple millions of spectators ogling it, in person or on TV.
The Denver Broncos turf manager and his team of 13 grass gurus are responsible for making sure this field of dreams is up to scratch. If he does his job right, he's certain some sportscaster, somewhere, will say, "The field looks great today!"
Which makes him inwardly groan, just a tiny bit.
"It's not for looking at," he said. "The question is, how's it gonna play?"
The play's the thing
Homeowner, cut yourself some slack. The high-profile swath of emerald at Sports Authority Field at Mile High is not like your lawn. Repeat: Not anything like it.
Recall, if you will, the dun- brown field at Lambeau
last weekend in Green Bay in which the 49ers squashed the Packers.
That grass wasn't dead. It was "fully dormant
," said Kurcab. That means the plants had basically hibernated
for a time, waiting for warmer temperatures (something above zero, perhaps) and longer days to send up new green shoots.
"But that field played fantastic
," Kurcab said. A sports field manager's priorities
are safety and playability. Appearance is always third. Not unimportant, but third.
Nor was the Packers' field frozen. Like Mile High, it has miles of heating pipes underneath it. Frozen ground "is a player safety issue
," said Kurcab, who's held his title for 30 years. Think expensive, potentially career-ending injuries. Then think twice about playing your next touch-football game on a frozen or drought-baked park field.
NFL fields have to meet tight standards
for shock absorption. In addition to frequent testing by Kurcab's team, an independent monitor for the NFL strolled the field this week at Mile High with a simple, yet fairly precise gizmo that looks like an oversized tire pump, taking hardness readings.
Traction gets measured, as well, with a gauge that pushes cleat-like blades into the turf, then tries to turn them. That measurement is less precise, and there are no standards it must meet, Kurcab said. "But we can compare ourself to ourself" with readings from other games.
Players like a lot of traction; they don't want to slip. Too much? Some research says there's potential for injury. It's an evolving and inexact science, he said.
The year-round crop
Your lawn is grown in soil, or what passes for soil in Colorado
. But the Broncos' field is grown in what's best described as a cross between a giant sponge and a 100-yard slab of lasagna.
From the bottom up, irrigation pipes and heat pipes (21 miles of the latter) wind through 4 inches of half-inch-diameter pea gravel. A 10-inch thick layer of 90 percent sand, 10 percent peat and porous ceramic granules, tops the gravel. The 10-inch layer provides the turf's long, intertwining roots with both good drainage and water-holding capacity. From this ideal medium emerge the tender leaves visible to gamegoers.
There's more you don't see: Running vertically through the root zone, and peeking out only about a quarter-inch above the soil, is the turf's deep-green secret: bundles of thin, polypropylene fiber. There is one four-fiber bundle in each square three-quarters of an inch — 30,000 miles of fiber throughout the field — to stabilize it. The Dutch-made turf reinforcement system, called GrassMaster
, was a six-figure purchase Kurcab spent two years researching and selecting.
"It's a great system, because it resists divots and tearing," he said. And it lets him boast that the Broncos play on 100 percent real grass.
But once again, it isn't like your grass at all. Most lawns are a blend of grass varieties. The Broncos' field has one type: fast-growing perennial rye
. Because grow fast it must.
With the GrassMaster system in place, patches of worn-out turf (midfield wears out faster than end zones) can't just be dug up and replaced. "We have to re-establish the grass cover from seed
," Kurcab said. So they do just that, whenever time between games allows.
The grass you'll see Sunday was overseeded four weeks ago, the day after the Dec. 12 game with the San Diego Chargers
(of which, let no more be said).
Some of the seed was presoaked in buckets of water on the turf shop's warm floor. The morning after the game was planting time for both wet and dry seed. Planting wet seed is handwork: Humans walk the field, flinging seed, because "once it's wet, it's like sticky rice — it gums up the machine," Kurcab said. The seeding machine then pokes holes, spreads the dry seed and moves all the seed into the holes. Then it is watered (Hunter irrigation heads, with Toro moisture, temperature and salinity sensors) and fertilized.
The field can't be kept too wet and warm — referred to as "juiced" — or fungus can start. And it can't get too dry. "You can always tell grass is trying to drought out," said assistant turf manager Chris Hathaway. "It'll start to get a purple cast."
So they watch it. Check it. Cover and uncover it. "Read and react," said Kurcab.
Every day, 24/7, the weather dictates almost every moment of what goes on with the Broncos' turf. But as the countdown to game time continues, the stakes and pressure rise.
Last weekend's snow and cold snap meant the turf team rolled out loosely woven covers onto the field on Jan. 3, before bad weather arrived. They managed to get the covers down before the wind began gusting. Sometimes waterproof tarps are laid out to keep the field from becoming too wet.
Hathaway and Kurcab — neither of whom have lawns of their own to stress over — watch multiple forecasts daily and pay Skyview Weather for morning updates and consultations.
In Monday morning's sunshine, it was time for Hathaway to roll back the permeable covers to reveal the tender, 1- to 1.5-inch-tall leaves of green. "We'll probably mow tomorrow," Hathaway said, "but hold off on the water."
In the guts of the stadium, Kurcab fired up a blower that forced warm air up through the field. You could see the thin rime of snow on the growth covers began to lose its grip.
Wednesday, the team painted logos on the grass. More days of testing, monitoring and the chore of clearing every speck of snow from the stadium (per NFL rules) lay ahead.
And more watching. "Read and react," Hathaway echoed.
On Game Day, the turf's dance card will likely be full starting at 5 a.m. with live media shots. It will get a fresh mowing, time and weather allowing. (The forecast calls for a dry, 43-degree game.) The 14-member turf crew will set up goalposts and benches and yardage pylons, heaters and nets, other fixtures of the field, making ready for pregame and the 2:40 p.m. kickoff.
Sometime in the fourth quarter, if all is going well, Kurcab might pay attention to the score.
Until then, "I watch from the knees down," he said.