Caring for your infield
The turf is the first thing fans see when they walk into a ballpark, and most base their impression of a field’s quality on the look of the grass. While great grass is an important component of a great baseball field, for most players and coaches, it’s all about the dirt. As sports field managers, the playability of the infield skin is a primary concern.
|Hand watering is part of the art of sports field maintenance. Note the quick coupler behind the mound and the cover plug beside it.|
Make the match
You’ll need to consider multiple factors when selecting the right infield mix for your baseball field. Budgets will definitely influence decisions from the initial costs of the materials to how they are maintained. You’ll want to find out what materials are available in your area, researching all the potential sites and pits to see what is local and affordable. Quick accessibility has obvious advantages.
When you find a source that is worth exploring, you’ll want to have the material tested. Standardized guidelines as developed through the collaboration of sports field managers and soil scientists are available through the American Society for Testing Materials (ASTM). These focus on the science involved, but so much of dirt maintenance comes from the experience of working with the materials through ever-changing conditions that you’ll want to do your own experimenting.
When you check out a pit that looks promising, ask for some samples. Put the sample material in some jars, get it moist and see how it reacts. You’ll want to work with the material with no additives at first to see how it sets up after it’s wet, and how it sets up after it’s dried out. You’ll want to work some of the material in your hand to see how it “ribbons” up so you can test the clay content.
The kind of dirt you decide on all depends on what you can maintain and if you have a tarp for the field or not. If you don’t have a tarp, you’ll want a sandier mix that will dry out faster after a rain so you can get the players back on the field. If you have a tarp, and adequate staff to work that tarp, you can go with a heavier clay content.
For the Texas Rangers’ field in Arlington, in the northern part of Texas, we use 45 to 50 percent clay, 20 to 25 percent sand and the rest silt. I prefer a very firm base, and I’m able to protect it.
Even relatively small adjustments in a baseball field can impact the dirt maintenance strategy. The Rangers had an established field, but a big crown extended across the infield from the pitcher’s mound. That made it hard to meet the MLB standards of a 10-inch differential between the mound and home plate heights, so we lowered the entire infield, basically flattening it out.
We didn’t make any changes in the infield material, but in creating a flat infield, we eliminated the .5 percent slope that had helped move water off the dirt surface. Now, if there is runoff from the tarp, the dirt holds it longer and is a little harder to dry out. There’s about a 1 percent fall starting from the back of the dirt to move surface water across the outfield grass.
Because the dirt is harder to dry out, I have to be even more conscious of how tightly the infield skin is compacted, but for optimum traction and playability, I want the heavier clay content for a firm base. I can make that top .25 to .5 inch softer, adjusting the depth and degree of softness depending on the day. That acts as a cushion that helps the ball stay down and protects the hardpan base from drying out too quickly. The higher clay content makes the material less mobile than a sandier mix. It’s easier to keep the consistency of the dirt and prevent low spots from developing.
Working the dirt
The first thing we do each day is check the weather conditions. We’re always looking a day ahead, anticipating what is going to happen and going by the percentages to determine how to prepare. If the next day is predicted to be dry and windy, we’ll do a nail drag during our post-game prep and flood the dirt, or just flood the dirt without doing the nail drag. If the next day is supposed to be cooler, the drying will be reduced a bit, so we won’t put down as much water.
|The Texas Rangers’ field.|
If it’s going to rain, we don’t want the water to percolate into the dirt. We’d rather have excess water puddle on the surface than have it soak in, so we want a harder, firmer skin. During the post-game prep work at night, we may leave the field dry and cover it. The tarp will pull up moisture. When we remove the tarp the next morning, we’ll roll the dirt and top it with about .25 inch of straight calcined clay. That gives us enough moisture so the dirt won’t explode during play if we don’t get the rain, as well as the right conditions to handle the rain if it comes.
In general, we like the firm, moist base. It’s easier to go from hard to soft than to make soft dirt firmer. Working the surface with a nail drag will make the dirt as soft as you want on top. Traction is key for safety and playability, and that comes from the firm base. It’s the corkboard effect. You want the players’ cleats to react on the dirt like a pin in a corkboard, a clean in and out.
Consistency is the goal. You want to get the dirt as consistent as possible from wall to wall and maintain it at that same level from day to day. The home field advantage comes when your team’s players know they can count on having the same conditions every day. You can make adjustments as coaches and players request them, but if a change is made, take the steps needed to make sure the entire team knows about it.
|Crew members team up with hand rakes.|
|Hand rakes and hand drags give the up close and personal touch to dirt work.|
On game day, start by watering the dirt evenly. Then see what’s drying out quicker and spot-water the second time so you’re only hitting those dry spots. After you’ve soaked the dirt wall to wall, go over it with a nail drag. The spots where your nail drag is not penetrating as deeply are the dry areas to go back and water again.
You’ll have some spots where the dirt stays wetter. Generally, those are your low areas, like the first base leadoff that gets a lot of action during a game. You can control that during a home stand by cutting back on the water you put down and monitoring conditions even more closely. You can fix the problem when the team goes out of town using a deep nail drag and working in some soil to hit the level you want.
Time is the deciding factor in the action to take if conditions are a little softer than you want. If you have time, use a smooth-drum roller. Match the weight of the roller and the number of passes to the degree of hardness you want to achieve. If time is limited, tire roll the dirt making multiple passes with a ride-on mower or utility vehicle. You can use that equipment when the dirt is a little wetter because it doesn’t stick to the tires as much as it does to the roller.
When our conditions are right, we’ll tire roll every day, hitting the areas that get a lot of foot traffic like the leadoff at first, the places where the basemen stand and the running lanes.
The rule of thumb is to begin field game preparations two days before the team comes back to town for a home stand. Make sure there’s a smooth transition from the grass to the dirt, using a rake, broom or stream of water from the hose to remove any skin material from the grass. Start building up the moisture level in the dirt, and make sure the base is firmly packed. The morning of the first game, add some new soil conditioner to the surface and fluff up that top section. If it’s a rainy day, just put a light layer of calcined or vitrified clay on top of the dirt.
Calcined clay will absorb moisture and hold it, gradually releasing it to the surrounding dirt as it dries down. With all of our new infield installations, we’ve started with the straight materials from the pit, and then added 4 tons of calcined clay from Diamond Pro, using a nail drag to work it into the top 2 or 3 inches. After it was thoroughly mixed, we packed it with a roller and topped it with a light layer of their vitrified clay.
|Dennis Klein uses a combination of ride-on equipment and handworkfor picture perfect dirt for the Texas Rangers. Here a JohnDeere field rake is used to pull a drag.||Hand watering keeps the dirt at the right consistency for play. Crewmembers lift the hose to keep it from dragging across the preppedinfield.|
Vitrified clay is a harder material, with smaller particles and a more consistent particle size. It doesn’t absorb moisture or break down as much over time. We use it as a surface buffer for the hardpan base.
If the umpires want to push the envelope and keep playing in rainy conditions, you’ll concentrate first on the plate and the mound. We scrape out any sloppy material at the mound and at the plate and fill those spots with drying agent, using a foot to smear it into the hole. On the dirt, key areas are the player positions and the running lanes. If we’ve anticipated the rain, the dirt will be packed to avoid penetration, so we’ll use the drying agent to soak up any puddles that have formed and work that moist material into the soft top layer or remove it.
When weather conditions are good, we’ll frequently put four of our crew on the dirt with asphalt hand rakes to look for pockets of calcined clay. We’ll knock down any high spots and fill in any low spots, moving it around for even distribution wall to wall. If we just pull a drag mat around we may float over some of the high spots. With the hand rake, we’ll feel some resistance where the calcined clay is a little thicker. We can push that extra material around putting it in areas where there is no resistance to the rake. When that is completed, we’ll nail drag followed by a finish drag using a light screen drag or cocoa mat to knock over the nail drag marks. Once the material is strategically placed, we want to make sure it stays there.
We always do our watering by hand, walking the field with the hose. We could use the irrigation system, but wind is a big factor within our ballpark, leading to uneven distribution of the water. With hand watering, we have control for precise water placement. Understanding how much water to put down in each area of the dirt is best learned through hands-on experience. It’s part of the “art” of sports field maintenance.
Dennis Klein is director of grounds for the Texas Rangers Baseball Club in Arlington, Texas.