Maybe your field didn’t come out of dormancy as you had hoped and there are important games coming up. Maybe your overseeded ryegrass has crowded out your bermuda- grass base and you know you’ll be in trouble by this summer. Sooner or later, as a sports field manager, you’ll need sod. For quick repairs, or to quickly establish a new playing surface, nothing beats sod.
At a professional stadium, regular resods are often part of the yearly routine to repair damage from major events like concerts, dirt races and/or damage from too many games. Concerts will be held at every professional stadium in the country this summer, best I can tell, with many hosting two or even three concerts this year. Jokingly, I say that the Turfgrass Producers International (TPI), the sod growers, are behind this resurgence in stadium tours we’re seeing.
The TPI may be the sports field mangers best friend, we don’t know. They love producing sod for sports fields, but they can’t read our minds, and we sports field managers have been lacking in our relationships with these great people. The professional sports field manager should know his/her sod producer very well. They can produce just the right sod for us, but we never visit them or really help them develop a program for our needs. All too often we wait until the severe damage happens, then go out and purchase whatever we can find. This is a recipe for failure for both the sod producer and sports field manager.
What is it exactly that makes good sports field sod? Soil dictates most of the equation, but not all. Sand, silt and clay content (soil texture) is probably where we should start when selecting a farm. It gets pretty expensive to bring in a “designer” soil to a farm, yet there are some practical ways to amend and change the soil texture out at the farm, at least in the top couple of inches. The rule of thumb is to match, as closely as possible, the soil texture of your field’s rootzone. I don’t like a distinct thatch line for sports field sod that will be heavily cleated; it’s just a loose, easily worn layer right at cleat depth. Instead, I like to see soil mixed into the thatch with a season-long program of core aerification, proper mowing and topdressing.
Except for maybe moderately used youth fields, cool-season sod should be harvested at least 1.25 inches thick, in my opinion, and even 1.5 inches is better. Thicker than that is rarely called for and often won’t hold soil when rolled up and rolled out, causing a bumpy field. This thick-cut harvesting adds substantial costs due to added weight and therefore truckloads needed, and takes away more of the sod producer’s precious soil. Still it will cost less than redoing the field after a few games. When cleat depth and sod depth are the same (.5 to .75 inch), disaster strikes, especially in the first season.
Obviously, you will want the appropriate grass species for your area and situation, but how you and the sod producer manage the sod will make or break the successful project. Maintain the grass as closely as possible to the field maintenance program of the field it will go to for at least one growing season.
Mowing height is very important in sports field sod production. Height of cut (HOC) is more critical for cool-season sod than warm-season sod. (Most C-4 grasses are already mowed short at our southern sod farms.) Some of the better sod producers keep a steady inventory of short-cut grass for golf course tees and fairways, as well as sports fields.
What does short mowing do for our grasses? Yes, it shallows the roots, but it doesn’t really reduce root mass in my experience. The result is a tight root mass in the top few inches of the soil, just right for sod-cut harvesting. Now we remove less of the total root mass when harvesting, and thus less transplant shock. By short-cut mowing, I am talking in the 5/8 to .75-inch range for typical cool-season bluegrass sods, and for at least one season as it establishes at the farm. This may be shorter than you plan to keep your grass field, but it doesn’t seem to hurt bringing it to a higher HOC once installed in its new field, within reason. In my experience, the worst thing you can do is bring in a sod grown at a higher cut to your field, then start scalping it down to your target height. Shorter HOC will add some cost to the sod, because the sod producer will have to mow three to four times per week now, but I think it is money well spent. The plant growth regulator trinexapac-ethyl (Primo) is a great product for use at the sod farm. It will reduce the mowing costs and also promotes a strong, tight root system.
Where does the future take us in terms of sports field sod? Many new advances in farming and harvesting techniques are starting or ongoing right now. For us sports field mangers, perhaps the most exciting is plastic-grown sod. The last several Super Bowls (played on natural grass) have been played on sod grown on plastic. No transplant shock because you don’t “cut” the sod, you peel it off the plastic. This allows for rolls to be very wide, up to 8 feet, meaning far less seams and wrinkling. But, the best part is the bulletproof toughness of the surface (See Super Bowl XLI, February 4, 2007, Miami in the rain). You want bomber-tight roots in your sod? Grow it on plastic! This could eventually mean roll-out temporary fields could quickly be installed and “rented” to a venue for a big game, and rolled back up and taken back to the farm for recovery and the next venue that needs it. Crazy.
Ross Kurcab, who holds a bachelor’s in landscape horticulture/turfgrass management from Colorado State University, has 26 years of turf management experience and is the first Certified Sports Field Manager). You may reach him at firstname.lastname@example.org.