A new natural turfgrass and synthetic turf hybrid system has entered the US market as a product named XtraGrass. The message that this can be a good thing for sod producers is coming from one—James Graff, co-owner of Graff’s Turf, Fort Morgan, CO.
“Some folks have a tough time wrapping their head around a sod producer and a synthetic turf company working together,” says Graff. “I think we can have our differences and our preferences. We want to see a natural grass field go in. They want a synthetic field that plays like a natural grass field. Those are separate goals. But when we combine them in a hybrid system we have a solution that keeps natural grass on the field while gaining the durability of synthetic turf. It’s an opportunity to work with the strengths of both because, in the end, we all want the same thing: a safe field that plays well.”
Graff’s Turf has been working with AstroTurf on the XtraGrass product and is the US distributor for it. Graff says, “Both companies view this arrangement as a partnership and everybody respects the expertise of the others. We let them know upfront that we wanted to be involved in the customer support through the grow in and the establishment process of the natural grass and they totally agree with that.”
Graff’s XtraGrass brochure explains the product like this: “XtraGrass is a network of synthetic turf fibers woven into a strong backing material and laid directly on a standard field base. It is carefully topdressed with sand and overseeded with your choice of turfgrass. The grass seeds germinate and grow between the synthetic fibers and through the backing. This creates a strong natural grass surface, which is more resistant to heavy wear. As the grass grows, 60% of the backing material biodegrades, leaving more room for the roots to grow through, while still retaining a strong support structure for the grass.”
The hybrid concept has been used before. SportGrass, a synthetic turf combining polypropylene blades and a tightly woven, synthetic mesh backing was installed on a well-drained sand-based field. Natural turf was seeded or sprigged into the synthetic turf and topdressed with amended sand. In another hybrid system, TS II (MotzGrass), the backing was burlap plus mesh, with the burlap intended to degrade over time. Both of these products were installed on fields in the US with varying degrees of success and all were removed and replaced with other field systems.
Graff says, “XtraGrass has a more porous backing than SportGrass or the TS II MotzGrass, which allows for much better root penetration. This product has been used in Europe for 12 years. They have refined the process and the product. We are getting a very well developed synthetic layer and good information on the grow in for those installations seeded or sprigged on the site and those seeded or sprigged by turfgrass producers to be installed as sod.”
Building on that background, Dr. John Sorochan, associate professor of Turfgrass Science for the University of Tennessee (UT) reports research is underway at the UT Center for Athletic Field Safety. “We have established XtraGrass plots with bermudagrass, turf type tall fescue, perennial ryegrass and bluegrass,” says Sorochan.
Initial research results on both bluegrass and bermudagrass plots showed XtraGrass offered an improved percentage of green turf cover compared to non-XtraGrass plots after 30 events. Clegg surface hardness values were less than 100 Gmax for all plots tested even after 30 events. Additional research is underway.
Sorochan did a great deal of research on the original SportGrass. Graff did the original grow in at the farm and then installed the SportGrass on Folsom Field at the University of Colorado. Thus both are aware of the problems involved with previous products and the steps taken with XtraGrass to avoid them.
Sorochan says, “We will be incorporating some of the new technology into our research, including the fraze mowing that is widely used on athletic fields in Europe. The process removes the surface organics, leaving the plant’s growth point and root system intact, basically allowing the turf to start over. We want to evaluate the effectiveness of fraze mowing on thatch management control, especially on the bermudagrass. We’ll also be gauging what impact fraze mowing makes on the synthetic fibers in terms of damage. We’ll continue to simulate traffic at various levels on each of the trial plots and look at the wear comparisons.”
The first XtraGrass field in the US was installed on Lakewood Memorial Field in Lakewood, CO, in June 2014. The field was built in 1973 and renovated previously in 1999. It is maintained by the Jeffco Schools Athletic Department. The field is native soil with surface drainage. The installation covers 83,000 sq ft. The field was overseeded on site with a mix of bluegrass and perennial ryegrass. This field is used for high school boys’ and girls’ soccer and college men’s and women’s soccer. It hosted 60-plus soccer games between late August and late October 2014. A tour of the field in January 2015 showed a good stand of grass.
“The infill is USGA spec sand which is not hard to find. There are no custom blends or proprietary mixes involved,” Graff says. “It’s a simple process. The site can be either a native soil that is graded for drainage or a sand field that is equipped with an in-ground drainage system.”
XtraGrass can be grown on plastic at the sod farm and then shipped to a location for installation or delivered and installed by the grower. Graff says, “We hope to work with other sod producers so grow-ins would take place in climate conditions similar to those of the installation site.”
Graff anticipates the interval from seeding to harvest of the XtraGrass sod will range from 60 to 90 days. He says, “The seed needs to root in enough to hold the plants in place. The strength for the sod to hold together is supplied by the synthetic base.”
Sorochan also sees growing the XtraGrass sod on plastic as an advantage. “The sod grower can select the root zone material to match the soil profile of the site. Root development is typically tighter in sod grown on plastic. The harvested sod would travel a shorter distance, so trucking costs would be reduced. The sod should have a better ‘shelf life’ as well.”
Graff says, “Up to this point, the solutions to problems with these hybrid fields were limited to a full field installation, either of the product or a straight natural turf field, a switch to synthetic turf, or a continuing struggle with existing conditions.”
That’s true with another concept, also introduced overseas, DESSO GrassMaster natural grass that is installed on a sand-based field with subsurface drainage. A specialized installer “sews in” artificial turf fibers that loop from just above the soil surface to a depth of 7.87 inches. It has been used at Sports Authority Field at Mile High, home of the NFL’s Denver Broncos, since the initial field installation but will be replaced in 2015.
With XtraGrass, replacement can be limited to sections, such as the goal mouth, a sideline, or the lacrosse creases. For replacement and repair, XtraGrass can be cut out and rolled up like regular sod. It can be moved to another area and reinstalled. It can be replaced with XtraGrass sod cut to the same depth. Graff says, “It takes no special tools or equipment or skills; just the same folks doing the same work.”
Sorochan adds, “I would think some of the facilities would want to be maintaining more XtraGrass sod on plastic as replacement turf for those high wear areas. The worn section that was removed could be laid out on the plastic for rejuvenation and recovery, allowing the field manager to keep switching the sod back and forth.”
Once established, maintenance is similar to a totally natural grass field. Graff says. “Coring is not recommended, but you can use solid tine aerification, either shallow or deep tine. That was not an option with the SportGrass system.”
Sorochan adds, “We’ll be working with needle tine aeration on it. With the smaller tines we can do closer spacing than with the standard solid tines. We’ll be tracking how that affects the degradation of the backing and how it impacts the root development of the natural grass.” Graff states, “We’ll be sharing and comparing research notes with the Europeans as well.”
Graff says the anticipated life is 8 years or more and that one of the initial European installations is being replaced this year after 12 years on that field.
Suz Trusty co-editor of Turf News from Turfgrass Producers International (TPI) wrote this article. Thanks to TPI, Suz, and Turf News for permission to reprint it.