Field sees nonstop action
Citizens Bank Park has hosted concerts by Jimmy Buffett, Bon Jovi and the Police, and it’s the home of major league baseball’s Philadelphia Phillies. The Phillies played on a synthetic surface for 33 years, so when the new stadium opened with a natural grass surface on April 12, 2004, it was a learning curve for everyone in the organization.
As Head Groundskeeper Mike Boekholder stresses, “These stadiums are multiuse facilities built to satisfy multiple objectives. We need to not just recognize that, but welcome it. Our role is making sure we accomplish the goals for marketing and community relations as well as providing a quality surface for baseball.”
Starting right for multiuse
The multiuse goal was the focus throughout the construction of Citizens Bank Park. It was the first field installation for Boekholder. He joined the Phillies in June 2003, with nearly 10 years of experience on minor league baseball fields.
The stadium design is fan friendly, with the entry at the street level concourse leading down into the seating bowl, where the field is the center of attention. That puts the field approximately 10 feet below the water table and required a 24-well dewatering system to control that level and keep the field from heaving out of the ground. In addition, the South Philly site was originally a swamp, so nearly everything is fill dirt. Since the makeup of the subgrade is unknown, it was covered with a 16 to 20-inch layer of crushed concrete for stability.
Boekholder says, “All the drain lines are trenched into the crushed concrete. That layer allowed work to continue through weather that otherwise would have turned to a mud bog or shut us down.”
A 4-inch layer of pea stone was installed over the concrete and topped with a 12-inch layer of 90 percent USGA sand and 10 percent Dakota reed sedge peat. The original design called for a flat warning track. The modification tipped the grade toward the playing field wall. That, combined with the subsurface drainage and lava top layer as specced, provides a workable surface that drains quickly.
Boekholder wanted a cool-season turfgrass mix of 10 or 12 varieties, predominately bluegrasses, that would provide good density with a low-growth habit, yet be aggressive for quick recovery and able to withstand the heat and humidity. The initial sod from Tuckahoe Turf Farm, selected for those attributes, was about 60 percent P104 because of its ability for fast recovery. Boekholder says, “The sod is grown on a profile very close to the USGA specs. Tuckahoe is willing to work closely with us to get what we want, and they’re about 40 minutes away. They now do all our sod work.”
The initial infield mix had some surface chip out that Boekholder wanted to correct. In late July 2005, he added about 27 yards of Field Saver amendment from Natural Sand Co. in Slippery Rock, Pa., to their infield mix from Tennessee. He says, “The two products bind together and cleat up beautifully, with little tear up and just the right amount of give to it. We now have the infield mix shipped to Slippery Rock to be mixed with the Field Saver and then shipped on to us, which does add to the costs, but it’s worth it for the rain resistance and workability—and because the players are very happy with it.”
Always researching, Boekholder tracks the NTEP data from Penn State and Rutgers, and has his own test plots at a sod nursery across from the ballpark. He says, “We have six blends of bluegrass and three bermudagrass that we’re evaluating for adaptability to our conditions. Tony Leonard with the Eagles switched to Patriot bermuda in the spring of 2007, and so far it’s doing very well. We’ve been continually improving our mix of bluegrasses, seeding in the best new varieties each year, and are happy with the turf quality, aesthetics and the speed of play, but we’re still watching the new bermudas. Our summers are not getting any cooler.”
Extra events run all season long at Citizens Bank Park, with camps and clinics often filling the concourse prior to spring play. April brings at least two college games on the field. Corporate batting practices, corporate and sponsor softball games, and suite holder and diamond club ticket holder events all bring more action to the field. Coaches’ clinics are held on many Saturday mornings. Youngsters from the crowd run the bases five or six times a season. In May, the Richie Ashburn Memorial Home Runs for Heart event includes two full days on the field, attracts lots of action and generates hefty funds. And, there are at least two weddings at home plate each season.
Boekholder says, “I meet with our community development and fan development personnel in January to lay out the event schedule for the year, fitting everything around the Phillies home games. Our goal, from the field use side, is to get as many of the extra events as possible packed in by the end of June, and then hit the annual concert. The weather can be oppressive in July and August, so we reduce our on-field extra event load to help relieve unnecessary turf stress. That timing gives us a window after the concert to manage the turf recovery and have it healthy and ready to go for the playoff run.”
As with construction of many major league ballparks, the team pays a sizeable chunk of the expense, and the city and the state chip in the rest. Boekholder says, “The Phillies have total operational control, and we do all the maintenance. Every event goes through us. It’s much simpler and more efficient that way.”
Once the schedule is laid out, Boekholder works with his assistant, Chad Mulholland, to map out the field maintenance program, allotting time for cultural practices, fertilization and preventive fungicide applications. They take a holistic approach to the field maintenance program, building turf durability and getting it hardened off going into summer to withstand the stress of the concert and snap back for top playability. That includes being proactive on environmental responsibility, considering the end result of every input and finding the best fit for the overall program. He says, “We’ve worked more organics into the fertility program. The organic product will be slower, but it can be more effective in building a more linear response into the growth curve.”
They’re applying .5 pound of nitrogen per 1,000 square feet about every 21 days, and then spoon-feeding additional nutrients sprayed in conjunction with Primo applications or injected into the irrigation system. They make a 6-ounce application of Roots 1 2 3 every two weeks year-round.
The program is continually adjusted to meet turf needs. Frequently used products include: Nature’s Safe 12-2-6 formula with 50 percent slow release and sugar Cal (chelated calcium); Sanctuary 8-3-6; and Micro-Pel, a granular micro package on calcite calcium. They apply ammonium nitrate as needed to promote faster top growth, but only when temperatures are cool. To stimulate upright growth in the bluegrass, they apply polyon-coated potassium (K) at the rate of .3 to .5 pounds of K per 1,000 square feet in the early spring with a second application in July.
The ballpark has held a major concert every year except the opening season. “There’s no way around the toll of covering a section of the outfield, 180 feet long by 60 feet deep, for five days,” says Boekholder. “Everything we do is focused on minimizing the damage to a controllable level.”
Their proactive approach to disease control uses constant monitoring of conditions combined with a preventive spray program. This method reduces the risk of turf loss, while using considerably less control material than a curative program would require.
Adding a Graden unit to the equipment package last year has given them the flexibility to verticut as needed. They use it about once a month to take out the dead thatch material and “beat up” the sward to thicken it. That is followed by topdressing with straight sand to help control the thatch and encourage bluegrass tillering. They also apply Primo at light to moderate rates to produce a thicker stand of turf. One Primo application is made prior to the concert, right before the floor goes down.
Boekholder says, “We run the SubAir unit to cool down the rootzone and keep up the oxygen exchange. The Terraplas does provide protection from the equipment and heavy stage structure on top of it, but with the hot weather, the grass plant is already struggling to survive, so with the two days of full sun we had this year the stress of being covered just shuts down the plant. Though the root structure is good, even when we pull up the floor and flood the irrigation, the leaf structure doesn’t want to take in nutrients. We run the injection unit with the irrigation system to give the leaf tissue a little feeding overnight.”
The field came through the 2008 concert fairly well. “We did minimal sodding where the hydraulic line on the crane broke while it was on the Bravo Mat roadway and seeped through the seams,” notes Boekholder. “That was a section about 8 inches wide by 2.5 feet long. In all, we put down about 200 square feet of sod. A section in the right field corner took a beating, as it always does, but we overseeded that and babied it along. We did get a lot of tip burning on the center field, even with the SubAir cooling that air pocket, since that area gets no shade.”
With the team opening at home against Boston on Monday, June 16, and being featured as ESPN’s Monday night Game of the Week, Boekholder and his staff had to combine short-term aesthetics with their big picture focus on turf health and playability. He says, “We used a light application of green dye on the center field tip burn to even out the color a bit, but we didn’t want to go too heavy and risk more foliar shut down.”
The three-day home stand with Boston was followed by a one-day break before the three days of home games with the Los Angeles Angels. Boekholder says, “It was nearly two weeks after the concert before we were able to work in the deep-tine aeration we’d arranged with an outside contractor. They used pencil tines to an 8 to 9-inch depth. We followed that with a shot of endoROOTS. By mid-July our staff could still see the stress as a darker green when we walked the field, but it didn’t show from the seats or on TV.”
Boekholder credits his staff’s commitment to quality and the cooperation and support of the Phillies organization for the success of their multiuse field program.
The author is a contributing editor for SportsField Management.