When I became the Superintendent of Grounds at the Sidwell Friends School in Washington, D.C., in April 2008, my first challenges were to improve the quality of our 2-acre, multipurpose, non-overseeded bermudagrass athletic field and to reestablish and preserve the cool-season turfgrass in well-worn common areas of the campus. In addressing these issues I wanted to integrate minimal, yet effective, use of pesticides in order to align the environmentally conscience ethos of the school with our turfgrass management strategies.
Sidwell Friends School, a Quaker private school, has a 15-acre, urban campus in northwest Washington, D.C. for our Upper School and a 5-acre suburban campus for our Lower School in Bethesda, MD. Our Plant Manager, Steve Sawyer, I and a crew of three groundskeepers are responsible for maintaining all turf and landscaped areas of the campuses, including plants that range from 80-year-old boxwoods to native species perennials. The perennial plants and flowers, which are grown throughout the campuses, including on the green roof of our LEED Platinum Certified, green middle school, are a primary aspect of our sustainable landscape initiative. Our athletic fields include two natural turf fields and one synthetic turf field (a second synthetic field will be completed in September 2010).
Challenges of multi-purpose bermudagrass field
Our bermudagrass athletic field is used for baseball and softball games and practices in the spring, then boys and girl’s soccer games and practices in the fall. Sidwell has varsity, junior varsity, and 7th and 8th grade teams for each of these respective sports. Additionally, the field is used for physical education classes throughout the school year.
This soil-based field had originally been Kentucky bluegrass and it remained so for decades. While searching for a better playing surface which would tolerate our high level of use, the school first sprigged the field with bermuda in the early 1990s when using bermuda in this part of the transition zone was not entirely common for high school sports fields.
Initially, the Vamont variety of bermuda had been planted but the field is now 75% Patriot hybrid bermuda after several seasons of sprigging with Patriot. We have found that Patriot offers excellent wear resistance for our level of use and a dark green color. However, in some areas of the field where drainage is inadequate, the Patriot bermuda has been susceptible to winter kill. Though turf blankets are highly recommended for winter protection of bermuda fields in our region, we have not yet invested in blankets for our field.
In the spring of 2008 the field was approximately 30 percent covered with annual bluegrass. The patches of dark green Poa growing in the light brown, dormant bermuda were highly unattractive; more importantly, our baseball coach mentioned that the clumps of Poa were making it difficult for players to field balls. Ground balls would often strike a clump in the infield grass and then veer off in unpredictable directions.
To immediately address the coach’s concern, I applied Revolver to all the Poa-infested areas at a rate of 0.4 ounces per 1,000 square feet. By the end of April, a tenacious crop of tufted knotweed, which had plagued areas of this field for years, had reared its ugly head. I made three successive applications of Momentum herbicide (Triclopyr, 2, 4-D, Clopyralid), spaced just 6 days apart. Each application was made in the morning, just after the dew had evaporated from the leaves, for maximum effectiveness. With the exception of a few stragglers, which were spot-sprayed in the following weeks, the Poa and the knotweed were under control.
Later, in early September 2008, I applied Dimension (dithiopyr) pre-emergent control to the field at a rate of 0.25 lbs. of active ingredient per acre which targeted the Poa before its seeding season. In spring 2009, the field was 95% Poa-free. Subsequently, it has remained under our action threshold for the field.
The bermuda is not actively growing for the first two thirds of the baseball and softball seasons and it goes back into dormancy during the final third of the soccer season. However, Steve and I have chosen not to overseed the bermuda because Patriot thrives without competition from perennial ryegrass. Furthermore, our not having to overseed this field with 1,000 lbs. of perennial ryegrass seed saves money for other priorities on campus and conserves water, as fall irrigation would be required with a fall over-seeding.
Because our bermudagrass field is used for baseball and softball as well as soccer, we faced a dilemma as to whether or not baseball and softball would have skinned infields beyond the grass diamonds. If we had chosen to have skinned infields, we would later need to install over 11,000 square feet of sod in the infield areas after every baseball and softball season so that soccer would not have to play on bare parcels of soil. Instead we decided that baseball and softball would play on grass infields (with cutouts for the bases, home plate areas and pitcher’s mounds) rather than having to sod two fully skinned infields every fall. The baseball playing surface of dormant bermuda has received positive responses from our baseball coaches and other coaches in the Mid-Atlantic Athletic Conference (MAC) in which Sidwell’s teams compete.
The few negative comments we heard about our dormant baseball field were in reference to the lack of color. Some asked, “What happened to our grass?” others inquired as to why we were “playing on dirt.” Many people in Washington, D.C. are Northeasterners, who are often not familiar with bermudagrass or its habits. This March, we contracted with Community Bridge, Inc., the local provider of YardGreen grass painting systems and had the entire field painted green. We hope that green paint on the field will please the baseball spectators as well as attract the sun’s heat, which may help bring the turf out of dormancy more quickly.
In June, after the spring baseball and softball seasons have ended, my crew and I cut down the pitcher’s mounds, dig and remove the infield soil mix from the skinned areas (we stockpile the infield mix for re-use the following season), and install 2,500 square feet of Patriot bermudagrass sod into the cutout areas of the field. When soccer practice starts in late August, the players have a fully green surface, with no indication that the field had been configured for baseball and softball just three months earlier.
Using hybrid bluegrass in common areas
Around the administration building, a 19th-century manor house called Zartman House, and other common areas of campus turf, we are using Scotts Thermal Blue bluegrass. Thermal Blue is a hybrid of Kentucky and Texas bluegrass varieties, which had been developed to be more drought and disease tolerant than existing Kentucky bluegrass varieties.
Use of Kentucky bluegrass in the Washington, D.C. area has become rare over the past 25 years because it would die during droughts, whereas tall fescue could go dormant during droughts and revive with fall rains. D.C. humidity also causes dollar spot disease outbreaks in Kentucky bluegrass. Therefore, most D.C. area lawns had switched to turf-type tall fescues in the 1980s despite the risk of brown patch disease and intolerance to wear for which tall fescue is also known.
Steve Sawyer had decided 5 years ago to try overseeding the common areas of the campus with Thermal Blue bluegrass mostly because of the hybrid bluegrass’s aggressive use of rhizomes to spread and fill in areas damaged due to foot traffic. Thereafter, we have found that the hybrid bluegrass has performed well under the intense pressures of constant foot traffic from students walking to class or playing Frisbee and by an annual spring graduation ceremony, which is set up on the back lawn of Zartman House, followed by nearly 3 months of summer camps with activities taking over nearly every square foot of turf.
We overseed the turf areas that receive the most traffic in both the early spring and the early fall. We core aerate and the slit-seed the hybrid bluegrass into the soil at a shallow depth of 0.38 inches. We lightly topdress all seeded areas with an organic material, such as Leafgro, to protect the seed and to enhance the overall turf quality.
After overseeding, we try to prevent foot traffic caused by students’ “cutting corners” across turf areas by installing homemade barriers using grade stakes and ropes. I bought a bundle of 1 x 2 x 36-inch oak grade stakes to use as fence posts. I drilled 0.875 inch holes at the top of the stakes through which the ropes are threaded. To improve the appearance of theses rough cut stakes, I sanded them and then applied wood stain and outdoor polyurethane to the stakes.
With the stakes set approximately 10 feet apart and a light brown 0.625 inch twisted nylon & polyester rope, I barricade the turf areas to be protected. Originally I had intended to take the stakes down after the seed had germinated but I received positive feedback from others on campus about the appearance of the barriers and their positive impact on the gardens. Additionally, these barriers certainly cost less than either metal of plastic post and chain systems that I had seen on other properties.
Environmentally conscience pesticide use
Our Integrated Pest Management (IPM) approach to pesticide use on the athletic fields and areas of campus turf is to try to keep pesticide use to a minimum. Because environmental concerns are prioritized at Sidwell Friends School, we have the leeway to take our chances with regards to pest infestations. Essentially, we are willing to tolerate a goosegrass outbreak, for example, in a turf area where students routinely congregate; therefore, we may not apply a preemergent control to those areas. Conversely, we apply preemergent controls to full-sun areas of the Zartman House lawn and on the bermuda field because summer annual weeds and grasses cannot be tolerated in these areas.
Our approach to broadleaf weeds is to crowd them out with healthy, dense turfgrass. We have implemented a vigorous overseeding and topdressing program for the fall and early spring (spring over-seeding is done only in high traffic of shady areas). Because white clover, for example, is partially a result of inadequate soil nutrient levels, we focus our topdressing efforts on these areas as part of our approach to eliminating the clover. With the exception of high profile areas, such as areas near sidewalks, we usually let winter annual weeds die on their own with the help of mowing and higher temperatures which come in mid-spring.
Higher bluegrass mowing heights of 2.125-2.25 inches in the spring and fall and up to 2.5 inches through the summer for the hybrid bluegrass have also been a critical factor in keeping weeds out of our turf. We have some densely shaded areas in which fine fescues are growing and these areas do best if they are never mowed. Sharpening our mowing blades weekly helps with preventing turfgrass diseases from spreading which is important because fungicides are never used on our campus due to concerns regarding inhalation hazards.
When we do make pesticide applications, we do so in the early morning hours before students and faculty arrive, or on weekends. We use Lesco’s Eliminate for broadleaf weed control because it has noticeably less odor; thereby, the application brings less attention and causes less worry to others on campus. Once we have decided what level of pest infestation is tolerable, our IPM approach has made our jobs easier while also availing us the environmental and economic benefits of using less pesticides on our campuses.
William T. Patton, Jr., is superintendent of grounds at the Sidwell Friends School in Washington, DC.