Consistency is key

The crew heads out with steel drags for a quick touch-up of the dirt between innings.
Photos by Steve Trusty.

The art of infield maintenance is focused on consistency. At all the baseball fields I’ve managed, I’ve always looked for the same kind of infield mix, testing out in the range of 60 percent sand, 20 percent silt and 20 percent clay. Those percentages aren’t the complete equation. The designation-sand, silt and clay-describes a size range, rather than a specific size. A sand particle could range in size from .05 mm to 2 mm. (Silt particles range from .002 mm to .05 mm; clay particles are less than .002 mm.) So, a 60-20-20 infield mix with sand particles at .5 mm is a different product from one with sand particles at 2 mm, even if the silt and clay sizing are identical. That difference will be reflected in how the two products perform on the same field under identical maintenance programs. Find a proven infield mix from a source with a long track record of consistency in the product it delivers. Wherever I’ve been, I’ve brought in dirt from the same source, Southern Athletic Fields in Columbia, Tenn.

The postgame drag generates feedback on the end of game moisture retentions. If I need to stop to clean the drag three times during this process, I’ve hit my mark.

Even more important than the components within the mix is moisture management. The type of mix doesn’t matter as long as you manage the moisture properly. At some point after a rain, the infield dirt of an outdoor field is going to dry down from too muddy to OK to play. Given a choice, we want it pretty wet with enough moisture content to hold it together and keep the dirt a little soft to take some of the sting out of the baseball so young players can handle routine ground balls. What we really want to achieve is a level of moisture that is just right all the time. The goal is consistency, with the infield dirt at the same level of moisture within all four positions whether the players move forward or backward or to either side. To create that, we have to apply the water evenly to all areas of the infield skin, but without getting water on the grass to avoid those wet balls fielders hate to handle. That means laying down the water consistently, every time, even if that’s five times a day. That’s much easier said than done.

Kyle Lewis fills in a depression in the home plate area with moist infield mix. Kyle Lewis rakes the moist clay “patch.”

Managing moisture is an art form. We must consider how to apply the moisture, how much to apply and how quickly it evaporates. We have to focus on the humidity, dew point, temperature, cloud cover, and wind direction and speed, always staying two or three steps ahead in our planning.

With an outdoor stadium or a retractable roof stadium like Houston’s Minute Maid Park with the roof open, weather conditions can vary from hour to hour. With the roof open, after the morning prep work is completed, I’ll flood the infield skin so we have standing water at 11 a.m. I want the dirt to be just playable when the players come out for batting practice, but that could be at 1:30 or 4 p.m. The amount of water I put down in the late morning will vary dramatically based on timing and weather conditions. Once players take the field, it’s tough to get any more water down. Yet, I want consistency during batting practice and for the night game, which typically runs from 7 to 10 p.m.

With full sun and brisk winds during batting practice, the dirt will dry out and require more moisture for game time. In Houston, we have 17 to 18 minutes from the time the teams leave the field to the point our crew moves off. I need to determine when to start watering and what nozzle size to use to control the amount of water put down to hit the right moisture levels to start the game and not become too dry and get firm at the end of the game.

With the roof closed at Minute Maid Park, conditions still vary. With the roof on, the air conditioning is running, but the controls are set differently based on the crowd size and the heat loading factors inside the building, which impacts dew point and humidity levels.

Kyle Lewis tamps the moist clay firmly into place in the home plate area. During the postgame repair of the home plate area, any loose dirt is removed from depressions in need of attention.

The challenge is greater when we have a night game outdoors followed by a day game indoors. I’m in my seventh year here, so I’m usually able to predict if the roof will be open or closed for a game. The sooner I know the decision, the better I can manage the moisture. I can’t soak the clay heavily anticipating the evaporation rate of the open stadium and then have the roof closed and expect consistency.

Korey Weikum uses a fan rake to move any kicked-up clay off the grass.

I monitor a combination of five Internet weather sites, looking for agreement within them, rather than relying on a single weather source. On some of these sites, the meteorologist will admit some confusion due to the interaction of weather systems. Even that is beneficial for my planning. Tracking hurricanes and tropical storms can be a big question mark for forecasters. So far this season we’ve had two tropical storms nearby, each bringing us several inches of rain. As a result, our field has spent nearly three weeks under cover, with only a few hours of sunlight during that time.

I can’t puddle water on the infield dirt when we’re consistently under the roof, but over time I’ve become more aggressive in how far I can push the moisture and still be ready for play by batting practice. The first couple of years I didn’t push it far enough and had some moisture from the subsurface base drawn upward, even though the surface remained moist.

When I walk and work the dirt every day, I can feel even small variations, and that helps me determine if the base feels too soft or too hard. I was concerned my subjective internal calibration may have been off, so I got a Clegg impact hammer for a more objective, scientific test to quantify the hardness of the infield.

Another element of consistency is the method and timing of dragging the skinned area. If you nail-drag the field at 9 a.m. one day and 11 a.m. the next, your infield dirt won’t have the same consistent feel. We follow the same routine every day. We start our day with the nail-drag, then we repair any damage on the dirt. Once that is completed, we run the screen drag over it. We also use that step to check the level of calcined clay on the surface. We know by how many screen “squares” are filled when we drag whether that top layer is consistent. If the count is low, we add more. I can start putting down the first water of the day at 10:15 a.m. We only use a coco mat in the afternoon if the dirt is a little too moist prior to batting practice.

During the game, we line up to hand-pull steel drags after the third and sixth innings. At the end of the third inning, the moisture level should be high enough that we can just barely pull the drags. At the end of the sixth inning, the drags should pull easily, leaving a smooth finish. After the game, I use the infield groomer to pull a steel drag. If I need to stop to clean the drag three times during this process, I’ve hit my mark. If I need to stop to clean the drag six times, the dirt was too moist; if I only need to stop once, my moisture level was too low.

Willie Berry smoothes the moist clay he’s packed into a depression by the pitching rubber during his postgame mound work.

I keep notes from every pregame preparation, recording the dew point, humidity level, temperature and wind speed, how much water I applied, what nozzle I used, how long I was on the field and the results that all produced. We could have a dew point of 20 one day and 60 three days later, so there’s a huge swing in evaporation rates. I want to consider all my options. These records help me do that.

My nightmare scenario is to be set up for an indoor game and have the roof opened just before game time because the dew point and humidity levels are so low it feels good to the fans. If I put down a light watering, the players are going to have a firm field by the fourth or fifth inning. So I’m always thinking two or three steps ahead. If that were to happen, what steps could I take to get to the moisture level I was after and the consistency I want them to have for play?

I have the best crew in the business, with Kyle Lewis doing the major repair work on home plate, Willie Berry tackling the game mound, Joe Johannsen working the bullpen mounds and Eric Jaramillo creating “Edges by E,” working by hand for a smooth transition from turf to dirt. Their dedication and team work ethic are great.

Dan Bergstrom is director of major league field operations for the Houston Astros. He’s a frequent speaker at industry conferences and contributor to industry publications.