Allen Johnson, CSFM, Green Bay Packers

Update on NFL natural grass fields

We asked some NFL head groundskeepers who have natural grass fields a few questions about their surfaces, past, present and future. Here’s what they said:

When you started this job, what kind of grass/surface did you inherit? What, if any, problems were there when you took over?

Tom Vaughan, Carolina Panthers: The field has always been 419 hybrid bermudagrass. No major problems. The field was only a few years old at that time. 

Tony Leonard, Philadelphia Eagles: Our stadium field was a DD GrassMaster field when we opened in 2003. This field performed very well the first year but slowly declined over the next few years. This was due to a heavy event schedule that included Eagles football games, Temple University football games, the Army/Navy game, along with concerts and many contractually obligated marketing events. Structurally, the field performed as it should have, but aesthetically, it looked worn by December with no ability to remove and resod.

Don Follett, Baltimore Ravens: When I started with the Ravens they had a Shaw Momentum 51 artificial turf field. It was in pretty good shape but it was starting to show its age.

Andrew Levy, Arizona Cardinals: When we opened State Farm Stadium in 2006 we had spent the previous 2 years working on a soil/grass combination that we believed would perform the best throughout an NFL season. We wanted a grass variety that would recover quickly and a soil able to resist compaction under the demanding stadium schedule. We built mock field tray plots in 2004 and tested dozens of soils and grass varieties. An important factor in this decision process was to have a surface that performed like our training facility where the team practices weekly. We had success with Tifway 419 in a 100% USGA sand mix at our facility; that previous success in combination with the results from our test plots, had us deciding to continue with that mix along with Staylock fibers tilled in to the sand. The fibers are installed to provide additional sheer strength in the soil late in the season once the field has been played on and begins to ware without compacting the surface.

Allen Johnson, CSFM, Green Bay Packers: When I first started, Lambeau Field had just been converted from a native soil field to a sand-based rootzone, with a playing surface that was a combination of synthetic turf and natural grass. We were able to make it look nice, but inherently it had some challenges delivering consistent footing. It was a great learning experience for me that keeps paying dividends today in how I approach managing our current playing surfaces.

Our practice fields were also both native soil fields and were converted to sand-based in 2004 and 2009.

How did you address any problems?

Leonard: In 2008, we decided to use Patriot bermudagrass. This did well but declined quickly in November. We decided at that time to sod overtop of the GrassMaster system with Kentucky bluegrass. With the help of Todd Vanek and King Sports Turf, we were able to accomplish this successfully. We continue this process of switching between varieties to this day.

Follett: My biggest problem was there were no standards of maintenance either here at the Ravens or from Shaw [the synthetic turf manufacturer]. No one seemed to know what needed to be done in order to keep the field in top shape. I asked a lot of questions and did a lot of trial and error to find out what worked and how often I needed to groom the field. That led me to create a set of standards that the Ravens used to maintain our artificial turf.

Johnson: It was a lot of research and talking with peers in the sports turf industry. Attending the STMA Conference was a great place to do a lot of that. I had to educate myself and then help educate upper management in our organization. Initially, we had given up on the combo playing surface and the sand rootzone at Lambeau Field was capped with native soil, which presented another unique challenge. We did our best to make that work, re-sodding as necessary with thick cut, sand-based sod. We even tried a “drill and fill” to create drainage channels through the soil layer into the sand below. The last few years of that situation, we were sodding the middle of the field with bermudagrass just for the winter games, and removing it in the spring. We were trying everything that we could think of to make the best of it. Meanwhile, I was intrigued by what Ross Kurcab was doing in Denver with another sand stabilizing product, which we eventually went with, on one of our practice fields in 2004, then the stadium in 2007 and another practice field in 2009. Ever since, we’ve been doing our best to make that system work for us.

Levy: Once we selected our grass/soil mix (Tifway 419 and USGA sand with Staylock fibers tilled into the profile) our next challenge was to maintain this surface to the standards we set out for during construction. We understood at some point we would need to sod some areas of the field, and in 2006 not many sod farms would grow custom sod (outside golf course grow in). Many sod farms were selling sand-based sod that did not match with our soil, in turn compromising the profile. This change in profile could affect water percolation, uniformity and turf density. After a late season resod in 2007 we reached out to Evergreen Turf based in Chandler, AZ to consider a custom annual field for our use, grown in our exact mix of sand and Staylock fibers. This partnership allows us to resod the field late in the season on a field that is identical to what we play on at the training facility as well as the one it will be replacing at the stadium, giving our team a seamless transition from each surface.

What is your surface now and how old is it?

Johnson: Lambeau’s field was rebuilt just last year with SISGRASS stabilizing fibers and Kentucky bluegrass as our natural component. Our practice fields have Desso’s GrassMaster fibers yet from when they were constructed in 2004 and 2009.

Vaughan: The current surface is 419 hybrid bermudagrass overseeded with perennial ryegrass. We rebuilt the field in 2016.

Levy: The field at State Farm Stadium is replaced two times annually once following training camp (held at the stadium) and once late season in preparation for the Fiesta Bowl and late season Cardinals games. With an established turf partnership in place that allows me to replace the field with a matching soil profile, I am able maintain the desired profile during the resod process. Since our inaugural season in 2006 we have played on Tifway 419 in the same USGA sand mix. I had the opportunity following the 2017 season to replace the entire sand fiber mix based on maintenance that was needed on the tray below. With 14 seasons of use I was excited to replace the sand and regain the angular sand properties that were lost over time due to use and mechanical work. With 14 successful seasons on Tifway 419 grown in our sand/fiber mix that is what went back down following renovations.

Follett: We now have a natural grass field. It is NorthBridge bermuda. The original field was put in 3 years ago but we re-grass the field each year. The current field was put in in November 2018.

Leonard: Our surface from July through late November is Northbridge bermudagrass and from December through mid-summer, Kentucky bluegrass. We still have the original rootzone and GrassMaster system as a base, but use sod 1½-inch thick throughout the year due to a heavy event load.

Do you foresee any changes/tweaks in your maintenance plan heading into 2019 season?

Vaughan: Plans can change based on weather and events. We may overseed ryegrass a little later this season due to our schedule.

Johnson: We are constantly trying different things to improve our management of these types of systems. We regularly renovate the surfaces with the TopMaker machine and grow back in from seed, but recently we have also been using the Allett machines with their various attachments. The turf rakes are great for combing through the grass canopy, grabbing the synthetic fiber and helping to keep it standing vertical and upright within the grass canopy. We also used the scarifying blades this spring in lieu of the TopMaker to thin the canopy and help get rid of the organic layer that was beginning to build on the surface.

Levy: Our field use begins in the summer with training camp when outside temperatures are well into the 100’s and ends in the winter when the nighttime temperatures are well below freezing. I do my best to encourage the 419 as late as I can into the winter by covering with grow blankets, applying green paint and on occasion bringing the field inside for the night when a hard freeze is in the forecast. I look forward to a variety of bermudagrass that will withstand the extreme heat of the Arizona desert as well as resist dormancy during the late season winter months, allowing the field to recover without overseeding. I continue to test new varieties and communicate with sod producers and universities to continue with this request. 

Leonard: I do not. This system has done well for us. The folks at both Carolina Green and Tuckahoe Turf Farms have done a tremendous job preparing a sod for us that we can install and play on immediately with no down time.

Follett: We do not see making any changes to our current plan for 2019.

Are there plans to change the surface in the next few years?

Johnson: Like a good football team, we are always evaluating what we are doing. We are trying the SISGRASS fibers on Lambeau at present, compared to the GrassMaster fibers. Each has unique characteristics. We are specifically interested in a fiber that has the ability to stay standing vertical within the turf canopy as long as possible. When these stabilizing fibers are standing upright within the canopy they really are at their best in providing excellent stability and consistent footing.

Levy: I believe a 12-month growing season for bermudagrass will someday be the future in the Southwest.

Vaughan: The rebuild in 2016 was extensive. I don’t foresee any major changes.

Leonard: Not at this time. As a stadium, we will continue to be aggressive in booking events that require planning, not only internally, but also externally with sod suppliers, installers, and field prep crews. As far as the performance of our base, it drains well and withstands the abuse it takes throughout the year. Not sure if this system is for everyone, but it’s been working here so far!

Follett: We will probably re-grass some time in November with the NorthBridge bermuda.