Prepping fields for special scenarios

Sports field managers are plenty used to wear and tear on their fields. Put 22 highly charged football or soccer players in cleats out on the turf, for example, and there will be some damage to deal with. But, there are even larger threats lurking, like a few thousand screaming teenagers at a concert or hundreds of ecstatic graduates at a commencement ceremony, for example. Preparing athletic fields for these kinds of special events, and then helping the fields recover afterward, is often more of a challenge than the day-to-day maintenance for sports competitions.

“We generally start about 10 days before the event, just really trying to get the turfgrass as healthy as possible before it gets covered up by the stage and floor panels we put out,” says Shaun Ilten, manager of turf and grounds at The Home Depot Center, of the preparation that goes into hosting a special event.

The Home Depot Center in California is home to two Major League Soccer teams, the LA Galaxy and Chivas USA, but the pristine pitch also hosts several concerts each year, most recently a performance by rock bands Linkin Park and Incubus. Shaun Ilten, manager of turf and grounds at The Home Depot Center, says a lot of work goes into making sure the field can stand up to events like this.

While the field can recover from most special events, one recent rock concert included a massive stage that was installed with the help of a 70-ton crane. It’s one of the rare times when a portion of the field needed to be resodded.

“We generally start about 10 days before the event, just really trying to get the turfgrass as healthy as possible before it gets covered up by the stage and floor panels we put out,” Ilten explains. This usually includes a heavy foliar fertilizer application. “We’ll include silica, which helps to strengthen the guard cells [of the grass blades], so when we do finally take the cover back up the turf will still have some life left in it,” he explains. Another foliar application is usually made about three days before the turf is to be covered up.

By removing the floor panels as soon as possible after the event ends and immediately applying water, the majority of the field was able to bounce back quickly from the concert. The area beneath the stage, however, needed to be replaced.

Also in the lead-up to the field being covered, Ilten adjusts the mowing height on his reel mowers. The field is bermudagrass and is overseeded with ryegrass, so the adjustments depend on the time of the year. “If it’s summer, I’ll cut the mowing height from 3/4 inch down to 5/8 or 1/2 inch. The less grass that’s there, the less there is to get damaged,” Ilten states.

Another reason for taking down the height of the grass, he notes, is that it will continue to grow once it’s covered, and there will be no chance to mow it at that point. “Once the grass is covered up with the floor, it heats up under there, which actually aids in the growing process while the grass is under there,” says Ilten. “Our last concert, unfortunately, came during our hottest week of the year. We had air temps around 90 to 95, so we had temps of about 110 to 115 degrees under the Terraflor. We were straight bermuda, so while that sounds bad, the grass really takes off in that kind of environment. Had that happened in October, after we overseeded, we would have been in trouble because any ryegrass would have been gone.”

The grass beneath the stage area was stripped out and that area tilled to alleviate compaction. An outside contractor was brought in to laser-grade the field back to its normal zero-percent grade.

As the concert approaches, Ilten waits as long as possible to put down protective flooring, giving the turf every moment possible to brace for being covered up. “If the concert starts Saturday night, we’ll put the flooring down on Thursday night starting about midnight. It takes about 8.5 hours to put down about 90,000 square feet of Terraflor,” he says.

While much of that work is done by an outside contractor, Ilten and several other members of his staff are on hand to assist and oversee the process to be sure there’s no damage done to the field when the floor is being put down. Nobody will care as much about the field as the turf crew that maintains it every day, he says. “There will always be things like someone driving the forklift too far and ending up with a wheel on the field,” Ilten cites as one example. “If we’re there, we can make sure they don’t go any farther and sink into the sand-based field. We’re there just to remind everybody to be careful with what they’re doing. If we have to put out a piece of plywood to protect part of the field, we’re there to do that.”

Anything that can be done to limit damage before it occurs is better and easier than fixing the damage afterward, he points out. “You have to try to stay ahead of the curve,” Ilten states, emphasizing the need to personally be there throughout the process. “The week of the concert I put in well over 100 hours,” he recalls. “The stage crews come in and they don’t care about the field, or at least they don’t know. It’s not their fault; it’s not their job to understand turfgrass. It’s just like I don’t understand how they’re putting the stage together, that doesn’t mater to me, I care about the grass,” he says.

Topdressing the field after a special event helps to even out any depressions.That kind of attention, and lots of water, are needed to help turf recover and get the field ready for play again as soon as possible.

Being there also allows Ilten to orchestrate how the field covering is installed. For example, the goal is to keep heavier equipment such as forklifts off the field. Instead, Ilten uses a John Deere Gator pulling a cart to move the panels out onto the field, which minimizes compaction.

Once the floor is down, the worst-case scenario, says Ilten, is rain. “That’s probably the worst thing that could happen. The floor has holes in it, which is good because on a sunny day it lets the grass breath and lets light through, but in the rain, the water goes through, and then if you put 10,000 people on it there’s going to be a lot more damage as it sinks into the ground.”

Commencement Challenges

At Stanford University in California, the football field at Stanford Stadium is a prized possession. During the football season, there are no special events scheduled on the field, says Joel Ahern, the school’s sports turf manager. In fact, except for football and an occasional international soccer match hosted during the summer, the only wear and tear the field receives is during commencement.

Each June the field is taken over for a total of about eight to nine days in order to prepare for and hold graduation ceremonies. “They set up a huge stage right in the middle of the field,” says Ahern. “We set up a little road system made of plastic so they can get their forklifts in and out to set the stage up.”

The protective matting has proven to prevent damage to the field, but Ahern has other areas that require a watchful eye. “We have to shut our irrigation system down the whole time, so there’s a lot of hand-watering involved,” he explains. The field is a 50/50 blend of Tif-2 bermudagrass and perennial ryegrass. “The bermuda holds up pretty well, but it takes a little more work to keep the rye alive,” says Ahern.

Families look on from the stands, so it’s mainly just the graduating students who sit on the field. No protective flooring is put down on the field, but Ahern says that the folding chairs don’t impact the field much. He notes that there is a little bit of wear on the aisle-ways, “but nothing significant that won’t grow out in a week or two.” Given that commencement itself is really a one-day event and the chairs don’t cause much damage, he doesn’t think it would be wise to use a flooring system, which likely would cause much more damage to the grass than it would prevent.

The large stage used for commencement does leave behind a little wear once it’s removed. “There’s quite a bit of yellowing to the grass, and quite a bit of hand-work required to repair low spots and things like that,” Ahern explains. The stage, which includes a roof, is stabilized with cables affixed to a series of anchors driven deep into the ground; to eliminate the need to dig up large areas of the field each year, the anchors have been permanently buried and are left in place. “Each year, we just use a metal detector to find them and then just dig a little hole to access them,” says Ahern. “Afterward, we just put the turf right back over them.”

Fortunately, there are no football games until the fall, so the field gets most of the summer to recover. “We wait until about a month before football season to do our aeration,” says Ahern. “That’s when we want our field to look its absolute best.”

Regardless of weather conditions, Ilten says his goal is to absolutely minimize the amount of time the turf is covered up. “We take it up right after the concert is over. I mean, if the concert ends at 11 p.m., we’ve got our first piece of floor pulled up by 12:15 a.m. We try to get it off just as quick as we can.” Taking the floor up goes quicker than putting it down, but is still about a five-hour process, he points out.

Once the panels are removed, Ilten is equally quick to start taking stock of how the turf has fared. “The first thing I do is put the water on. We’ll actually do that even when the flooring is coming up. Once an area has been cleared, I’ll turn the water on there,” he says. “The grass is definitely in shock, so I’ll put on as much water as I can.”

The following morning, Ilten sends his crew out with backpack blowers to try to “stand up” all of the grass that’s been packed down. They will also gently rake over the top to help the grass return upright. “Other than that, I try to limit the amount of stuff that we do just because the grass needs a day or two to just be left alone and try to recover,” he says.

He does continue to water the sand-based field during that day or two. “I go about three times my normal watering cycle, just because the field probably hasn’t seen water in about four days at that point. So I really run the water and let it puddle up,” says Ilten. “And I run a magnet over the whole field as a precautionary measure, just to pick up any screws or bolts or anything else the stage crew has decided to leave behind for us.”

After the field has had a chance to rest for a day or two, Ilten and his team do a deep-tine aerification. “This helps give the roots a little bit of oxygen and reduce some of the compaction that’s taken place,” he explains. “Then I come back out with a heavy foliar application that has a bunch of nitrogen and phosphorus. The nitrogen helps get the leaf blade to grow and the phosphorus to give the roots a little kick and let them know they can start growing back down again. You can really see the results within a day or two what the foliar has done.”

It’s usually about three days before Ilten resumes mowing the field, and he gradually raises the height back up to its standard 3/4 inch. He also recommends topdressing the field, which helps to level out any small depressions or indentations that have been made on the field. At that point, he says, the field is usually well on its way to being ready for soccer once again.

Of course, there also are times when a special event creates an extreme amount of damage and serious field repairs are needed. That was the case during the recent concert at The Home Depot Center. “They had to drive a 70-ton crane out on the field to put up eight pillars that held the stage together,” says Ilten. “I just cringed when I saw that crane going out there; I think that’s a turf manager’s worst nightmare.”

He says that’s one of the only times that he’s needed to resod part of the field following a concert. “I hadn’t planned on it, but the turf was just completely black under the stage and where the crane had driven,” he explains. Thanks to the use of protective flooring, there’s usually not as much damage from the general seating areas as there is where the stage sits, Ilten notes. In this case, about one-quarter of the field needed to be resodded beneath the footprint of the stage.

To prepare for that, the existing sod was stripped out and that area tilled to alleviate compaction. An outside contractor was brought in to laser-grade the field back to its normal zero-percent grade. “We also added amendments – some 0-0-15 and some 5-3-1 – just so when we lay down the new sod it gives the roots something to look for,” says Ilten.

While serious damage can’t always be avoided, Ilten says that most special events at The Home Depot Center are held without the need to resod. With proper planning, careful oversight and the right level of care for the field afterwards, the field can quickly recover from most special events. “The most important thing is to go into the event with the healthiest turf you can,” he advises. “I think that’s what gives it the best chance to withstand everything. You’re facing a battle, but this way you at least have a fighting chance.”

Patrick White is a freelance writer and editor who is always on the lookout for interesting and unusual stories.