ST. LOUIS • When Bill Findley came aboard as the assistant head groundskeeper at Busch Memorial Stadium in 1996, the old ballpark was just switching over from artificial turf to grass.

During the artificial turf days, concerts and large events at the stadium were a relative piece of cake for the groundskeeping staff. For the U2 concert that took place on sweltering Sunday evening, an event that drew more than 50,000 to the current stadium, the logistics have been enormous and exhausting.

When all is said and done, when the Cardinals return home to face the Houston Astros on Monday, once again they will be playing on a vibrant — and entirely new — natural grass field. At least, that's the plan.

This week's heat wave will complicate it.

"It's a dual situation, but what Mother Nature is throwing at us is really unexpected," Findley said. "The sustained heat they have in the forecast for the next 10 days is going to make our job that much tougher."

The job began moments after the Cardinals closed out their pre-All Star break schedule with a home victory on July 10. Moments thereafter, Findley and his company of 23 began tearing up 110,000 square feet of baseball bluegrass to accommodate the approaching rock concert.

Two sod harvesters scraped up the turf, cutting it into 4-foot-wide strips and twirling it into giant sections. The rolls of turf were lifted onto trucks and hauled away, some recycled elsewhere, some too marginal to be replanted. The field at the stadium is laid atop a sand base, which allows it to drain well. When all the grass had been removed early last week, the stadium floor essentially was a giant sandbox.

"This is pretty much a complete destruction of your field," Findley said of the concert. "When they bring this thing in here, and set it on your field for a week, no grass is going to survive that."

The "thing" to which Findley referred to is better known as "the Claw," a massive superstructure that houses each U2 performance. It is the largest concert stage ever assembled, a four-legged, spiderlike structure that hovers over the concert floor, holding speaker systems, lights and video elements.

The steel assembly is 167 feet tall and transported to and from concert sites by 120 trucks. The U2 tour includes a production crew of 137 workers, which is supplemented at each concert location by some 120 hired hands. Daily costs of the production are estimated to be around $750,000, which does not include the actual construction of the stage.

There are three versions of the stage in use, and all three will be for sale when the tour wraps up at the end of this month.

Perhaps the most field-impacting aspect of the concert production was the installation of a large aluminum floor to support and stabilize the equipment, the construction and the actual concert. The thick arena decking was pieced together in panels that weighed 400 pounds apiece and took six people to move. No baseball field could survive such suffocating abuse.

"There's a misconception out there. People think we replace the field like this every year during the All-Star break," Findley said, "and that's just not true. This is the first time we've had to do it."

For clarity, the post-artificial field at Busch Memorial Stadium regularly got replaced during All-Star breaks, because the grass was more difficult to maintain at the old yard. But the current stadium, which opened in 2006, is a slightly kinder place for root structure and turf management.

The U2 show was the third rock concert at the current ballpark, preceded by the Dave Matthews Band on June 7, 2008, and the Eagles on June 24, 2010. Neither of the previous two shows approached the U2 production in terms of size and scope.

And nothing Findley observed while growing up in Augusta, Ga., prepared him for a massive steel stage. Nothing he studied at the University of South Carolina, or learned during four years in the Navy, covered massive stadium transformation.

"There's nothing that can really prepare you for something like this, except just getting out there and doing it," Findley said. "My crew and I have been through a lot. A lot of my guys have been with me a long time. You just take whatever comes at you and do the best you can."

An unusually cool summer in 2008 allowed the grass to survive the Dave Matthews concert unscathed. Last year's Eagles concert required patchwork sodding in the outfield. But the U2 event has presented a more ambitious challenge.

Over the next three days, the stadium crew will be laying the new field, unloading 14 trucks full of sod each night. The bluegrass blueprint is to have the infield down by tonight, with the remaining sections of the diamond to be in place by early Friday morning.

There will be no rest for the weary. Most of the work will be done at night, both for the health of the grass and the crew. The sod is arriving by trucks from Fort Morgan, Colo., provided by Graff's Turf Farm.

"They just do an amazing job out there," Findley said. "This is some of the best bluegrass you'll ever see. They keep it very tightly mowed on the farm, and it's almost like the turf you see on a golf tee box."

The grass is grown on an all-sand foundation, which is ideal for Busch Stadium in that it will interface with its natural environment. Theoretically, the roots will adapt more easily. But the theory isn't based on oppressive heat.

Not only was the current heat wave tough for concertgoers on Sunday night, but it also is going to make the field makeover effort precarious. The forecast over the next six days, until the Cardinals return, calls for daytime highs in the upper 90s and nighttime lows in the upper 70s. That's a lovely outlook for incubating eggs, but it's nightmarish for transplanting new grass.

You don't need an agronomy degree to understand the predicament. The sod is being cut and loaded into trucks in Colorado, transported for two days, introduced into a new and oppressively hot environment, while being encouraged to make itself right at home.

It would be easier to plant square pegs in round holes.

"The (concert construction) situation is not horrible, we can do what we need to do," Findley said. "But this weather makes our job that much tougher. You're bringing in brand-new sod which doesn't have any root system to it whatsoever. You're trying to keep it hydrated in 100-degree heat. I mean, it doesn't matter whether it's bluegrass, zoysia ... it's difficult."

To help fight the heat, the sod is being shipped with a slightly thicker soil base. Under more favorable weather conditions, the turf would conform to its new environment within a few days and the ballplayers wouldn't know the difference.

"It's only going to be down three days (when the Cardinals return), so it's not going to be perfect by any stretch of the imagination," Findley said. "It'll be playable, hopefully. But you'll be able to tell, be able to see some of the seams.

"Once we can get it out of that shock mode, it should respond pretty well. But if we get this kind of heat for another 10 days, it's going to take it longer. That's the problem with this industry in this part of the country, the weather is just so difficult. It's hard to really prepare for what you're going to get."

The Cardinals will be back in a few days. Come hell or St. Louis weather, Findley and his crew will have a field ready for them.

EDITOR'S NOTE: An earlier version of this story contained an incorrect figure for the grass area at Busch Stadium. This version has been corrected.