Baseball Dirt Specifications

posted on February 6th 2007 by Troy Frazier

Baseball Dirt, Infield Mix Specifications

My last piece on baseball dirt seems to be very popular so I thought I should write more about the subject. Standards for infield mix vary, but the general guideline is to get dirt with more sand than clay or silt. ASTM has a very detailed standard concerning infield dirt. The following is a brief except of standard F2107.

"In general, top mixes with 6 to 10% in the <53 ?m fraction are better suited in rainy climates due to the greater internal drainage. In dry periods, they will require frequent irrigation to minimize dust and to provide a firm surface. Top mixes with 11 to 20% <53 ?m, will drain more slowly but will retain more water. Frequency of irrigation will be less. The mixes will be more cohesive and will be more difficult to loosen when they compact."

Particles less than 53 ?m (micrometers) are considered clays and silts by the ASTM. F2107 generally calls for infield mixes with less than 20% clay/silt. I talked with the head of the committee on F2107, and he said a change is in the works to bring mixes with as much as 41% clay/silt into tolerance. This change makes sense to me because almost all the infield dirt used in Ohio has greater than 30% clay/silt content some as much as 60%. I find that more than 45% clay/silt gets very hard in dry weather.

The ASTM and many dirt suppliers don't break out silt as a separate value. Silt is a particle size between clay and sand (3.9 to 62.5 ?m Wentworth scale). Silt is generally regarded as bad. High end suppliers like Beam Clay advertise very low silt content (<8%) in their premium bend infield products. Below is a quote from James Kelsey at Beam Clay,

"As you can see, our spec allows 0-8%. Generally, we're in the 3-4% range. Many producers of infield mixes only refer to sand and clay content. What they call "clay" actually contains sand, silt and clay, often very high amounts of silt. Silt separates, causes wind and water erosion, worsens drainage in wet weather and compaction in dry weather, and consequently requires more infield conditioner to keep the infield playable. Many producers of infield mixes use sediment pond materials from sand & gravel operations. These are primarily fine sands, silt, and clay. We go to much trouble to use uniform sand for drainage, very low silt content, just enough clay for firmness and distinctive reddish/orange color, and process in a way that minimizes any separation of ingredients. We only use all natural ingredients."

Link to Beam Clay specs.

Beam clay often supplies professional teams. They are based in New Jersey. They are a great group of people to talk to about baseball dirt.

Shipping is an important consideration for baseball dirt. Local shipping reduces the cost of a good infield mix considerably. Beam Clay offers regional suppliers for most states.

Around the Cleveland, and Columbus area we use Jones Topsoil as our infield mix supplier.

They use a blend of 55 to 65% sand by weight with the remainder of the material being silts and clays. Organic material is < 2%, and the material is passed through a 3/16 screen. We've been very pleased with its performance, and it is very competitively priced.