I was visiting with a school board member of a very large school district a couple weeks ago and he made a statement that was very concerning. His statement - “I thought our only option for our football field was what we have (native soil) or synthetic. I didn’t realize there are different options.”
- Native Soil - This is the rootzone composition of most high school/recreational playing surfaces. A native soil rootzone is simply using the soil that is on site, grading the material to a certain grade and establishing natural grass. This is the most cost effective method, but also often times is poorly draining and prone to compaction. How can you determine the composition of your native soil? How quickly will it drain? Simply pull 2 different sample for testing. First - An Undisturbed Core Sample. Second - A Topsoil Quality Test. Both tests are critical to determine the composition of the native soil, percent of surface grade and assist in determining the possibly of the next rootzone......
- Modified Native Soil - This rootzone follows a similar path as listed in #1 except sand or organic matter is added. How much? What type? Those questions are answered with the Undisturbed Core Sample and Topsoil Quality Tests. Just add one load of sand and till it in? Probably not. Oftentimes, modifying a rootzone is more expensive then the next rootzone option.......
- Sand Cap/Cambridge - Otherwise known as The Spartan Sand Cap. In this application subsurface drain lines are added and sand is aggressively topdressed across the playing surface - THIS WORKS! A great “low cost” option for high school/recreational surfaces.
- Sand Cap Rootzone - This rootzone is simple as well. A rootzone similar to a USGA rootzone, in regards to subsurface drain lines but the gravel layer is omitted. At a six inch depth, this is the best “apple to apple comparison” to to a synthetic turf rootzone.
- USGA Rootzone - The “best” natural grass rootzone, this uses a gravel blanket along on top of drain lines with 10-12 inches of rootzone sand on top of the gravel. This surface will drain in excess of 15 inches an hour. Simply put, this is a “rainout proof” surface. This is the rootzone used on most if not all high end athletic fields - ie - the ones you see on TV. As the school board member stated - “I wondered how they played in a rainstrom without the field becoming muddy?”
- USGA - Stabilized - The “best of the best” for natural grass. An example of this would be Xtragrass. Using a stabilizing system in addition to a sand based rootzone, this system can take a similar amount of play as a synthetic surface without using crumb rubber
- Gravel - Synthetic Turf Base - This option is for synthetic turf only. The rootzone consists of subsurface drainage underneath a 6 inch gravel blanket.
So, there are many rootzone options. It is concerning that oftentimes a sales rep will compare a non laser graded 25 year old native soil playing surface to a new synthetic field. Of course the new synthetic field will look and drain better than a 25 year old playing surface! One size does not fit all!