What is Baseball Infield Clay?
Over 80% of the game of baseball is played on the infield, which is why the infield clay is one of the most important components of the field.
Recently, I have received a couple of emails asking the question, What is the infield clay really made of? In layman terms, it is composed of three materials. Sand, clay and silt. The tougher question is what are the percentages of the content of each material, and the particle size of the sand. The composition is the true science of the infield clay even though the daily maintenance performed on these fields at a higher level is sometimes considered more of an “art”. Most companies that provide ball diamond mix state they have a something like a 60%-70% sand ….20%to 30% clay and 10% to 20% silt. Most infield clays and baseline clays are about 5 inches deep. Bellow that there is a level of sand and pea gravel on the big league fields.
As a general rule of thumb this distribution makes sense, but the key factor is the sand particle size which comes in numerous variations from “gravel” to “very very fine”, Angular and round and so on. Separate tests are performed on the infield clay mixture to determine the sizes and distributions of materials as well as the percolation rates which give you an idea on how it may drain or dry out. Normally infield clays do not drain very well and are not really supposed to depending on the level of field you have. You can obtain pretty much any type of blend you want from numerous clay companies. The geographic location and your budget will drive your selection to the material you can obtain.
When I worked for the City of West Palm Beach managing the spring training facility for the Atlanta Braves and the Montreal Expos we used a higher sand base 75% sand 15% clay 10% silt with a medium course level sand that allowed the rain to pass through the infield clay a little easier. These days I use a more stable clay with a analysis of 40% clay 50% sand and 10-20 silt. This is a real heavy mix but can take a ton of abuse. Where you live and how much the field is used also drives the decision on the type of infield clay you may have.
Everyone that has been to a professional game notices the time the crew takes on dragging and watering the infield clay before the game. The key to a good infield and making it a great one is how you manage the moisture level in the clay. Kind of like the Goldilocks & the three bears nursery rhyme ” not to hot, not to cold, etc…your infield clay needs to hold the right amount of moisture to not be to soft, to dry, to hard or to moist. Companies now manufacture a material which is known in the industry as a soil conditioner. It is applied to the top of the infield to help control moisture. These materials are sometimes called, “Diamond Pro” , “Turface”, “Terra green” , “Pros Choice” etc…they are basically a calcined clay heated to a very high temperature and sized and colored to your liking.
Maintaining the infield’s moisture level requires consistent monitoring and maintenance. Coaches and players are continually giving you feedback on the condition of the infield helping you determine where you need to be with the moisture and maintenance methods used. Based on the weather, climate, time of year and even the team that is on the field, your maintenance of the clay could change a little on any given day. Its one of the most unknown interactions in professional sports. That’s why they sometimes call the groundskeeper the 10th man on the team!