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Playing in the Dirt: Keeping grounds at Minute Maid Park

From the expanse of green grass to the perfection of the dirt, baseball's church is its field. TCB's Terri Schlather spent some time with Dan Bergstrom, Astros' Senior Director of Major League Field Operations, to uncover a little about what goes into making Houston's Field of Dreams.

Troy Taormina-USA TODAY Sports

As I walk into Minute Maid Park for any given game I can’t help but take in the sights and sounds. Before buying a drink, before getting food, before heading to my seat I walk to the back of a section of seats and look at the field. There’s no particular reason for it, perhaps just to remind myself that I’ve come to church once again.

I’m often amazed by the expanse of green, the perfection of the dirt, the field a pristine stage upon which men play baseball. It’s a stage that doesn’t get talked about until a ball bounces a weird way in the grass or rolls over something, perhaps a lump in the dirt. Those are moments that an MLB groundskeeper is doing everything he can to avoid. After all, a pristine stage for baseball is their job all day every day.

In Houston, there’s a team of six full time groundskeepers under the direction of Dan Bergstrom, Senior Director of Major League Field Operations, that ensure the Houston nine have the best field possible upon which to play a game of baseball each day. Their days are often long and filled with tasks the average fan doesn’t routinely think about, but still inherently knows must happen.

At 9am the first shift of crew begin their work on the 130,658 square feet (about 3 acres) of baseball field. Most of that expanse is covered in TE platinum paspalum cultivar grass, the third variety of grass that has been used in this ballpark. When it first opened, then Enron field was covered in Bermuda grass, the grass most sports fields in the south utilize. But Bermuda grass loves the sun and when you are taking care of a field in a ballpark that doesn’t see sun all day everyday thanks to the wonders of a retractable roof, the upkeep becomes problematic, so seaisle paspalum was used for several years until 2008 when the club switched to paspalum platinum TE cultivar for the 2009 season.

Bergstrom explained the way that grasses can be updated like the model of your car. Genetic improvements happen with each model, much the way car manufacturers keep improving what we drive. When a genetic modification is made to turf grass that would serve Minute Maid Park well, it’s something they pay attention to and consider. "The retractable roof is challenge number one. You need sunlight to grow the grass, so challenge one is finding a grass that does better without a lot of sun."

Paspalum grass is a warm season grass that does best and thrives in areas that are persistently cloudy, thus its success as the turf for MMP. The roof at MMP allows for some natural sunlight on the grass to help things along, but the grounds crew periodically uses artificial light to help facilitate growth, particularly in areas that don’t get natural sun even with an open roof. By putting sunlamps to work – some lit with metal halide bulbs and others with LEDs that provide the exact wavelength for plant growth – the team is able to ensure that even the darkest corners of the park have grass that is healthy and the dark green we have all come to expect.

But what about rain? "Rain on the field is rare. Happens once a month or less," reports Bergstrom. When it comes to watering the grass, the roof is the ally of the grounds crew. When the roof is closed there is little to no evaporation so the requirements for water on the field are rather low. During a seven-day home stand with the roof closed, the sprinklers are likely not to run at all. When it’s open, they run every second or third night depending on area weather conditions – temperatures, humidity, etc - that are watched closely by the team. That irrigation system includes 4,406 linear feet of a PVC pipe and a total of 78 irrigation heads to help get water where it’s needed. A bit bigger than the one you may have at home.

Once the grass is well fed with both sun and water, it must be maintained. The home grass for the Astros is kept mowed to ¾". "It seems to be the height that keeps pitchers and hitters happy." It's a theme you hear from Bergstrom - keeping players happy and ensuring fair play of the ball. It's top of mind for the Houston grounds crew. They take pride in providing the best field of play they can. It's evident in the way Bergstrom talks about the field and his team.

Of course the height of the grass isn’t something the fans may notice, but the pattern of color is. The patterns we see in the field are simply light and dark stripes of the grass. It’s achieved by how the field is mowed, but not in difference in height as some may speculate. All the grass is mowed to the same height.

Every leaf blade of grass has two sides and those two sides have two colors, so based upon the direction the blade leans, we see a particular color. The mowers used by the groundskeepers have rollers that lean the grass the desired direction. In Houston, that pattern you see is less about looking cool and more about functionality. If mowed the same way for too long, the grass will effect the way the ball rolls, so the crew keeps the mowing patterns relatively simple in Houston and straight to each outfielder, giving them the truest bounce and truest play of the ball.

It’s the grass that gets our immediate attention in a ballpark, but if you ask Bergstrom where they spend the bulk of their time, he doesn’t hesitate when he says, "On the dirt. Six of the nine players are on the dirt for each pitch, so we take it more seriously. All morning, from 9am-4pm, there are two people who are only working on the dirt." Moisture management of the infield dirt is key. Sunny days and an open roof on windy days could lead to drier dirt that needs watering every hour. The variability added by the retractable roof makes the dirt perilous to manage. They strive for a perfect consistency of soft and malleable, only letting it dry out and harden if there’s an event happening at MMP other than baseball which requires some protection of the field.

The players have opinions about the field and those make their way back to the grounds crew via the coaches. They hear about who likes the grass taller and shorter, if the pitcher likes the mound a certain way or the dirt is too soft or too hard. And generally, the crew strives to keep them happy and create a field that offers fair play to everyone on it.

Mostly the crew is a nameless and faceless bunch to fans; we see the part time team on the field dragging the infield in 90 seconds after the third and sixth innings, but most of us can’t name one person on the team that maintains the field. I don’t think the crew minds being predominantly anonymous, but when asked about what he thinks the fans should know about his team Bergstrom mentions one name they’re particularly proud of.

Willie Barry is the man who has spent 42 seasons keeping pitching mounds in shape in Houston. Back in the days of the Astrodome Willie did it all and his efforts and dedication are well revered. "Pitchers are particular and Willie keeps them happy." So the next time Dallas Kuechel has a good outing, give an internal nod to the work of Willie Barry who has no plans to hang it up and continues to work the mound each day.

That crew that started out at 9am for a 7:05pm game? Their day can be quite long. Many will continue to work on the field until 11pm that night after the game is over. A subset of the crew will come in at 9am and work up until batting practice and yet another group comes in to do the 5-11pm shifts – the group you see dragging the field during the game. All in, a team of a fifteen to eighteen people are working on the field on a game day in Houston. All of them with the same goal: keep the field a pristine stage upon which men play baseball.