Key Points
The consulting agronomist will test the irrigation water source and topsoil and then work with the golf course architect to determine the best turfgrass species and cultivars for the golf course’s greens, tees, fairways, maintained rough, and native out-of-play areas.
The National Turfgrass Evaluation Program (NTEP) provides comparisons of the latest cultivars based on key physical characteristics - color, density, resistance to diseases and insects, tolerance to heat, cold, drought and traffic – and is a good starting point for the turfgrass selection process.
The optimal growing temperature and humidity for a cool season turfgrass is different than that for a warm season turfgrass. They also differ in how they are established (seed or sprigs), how they propagate, and how they are maintained.
All turfgrass maintenance practices (e.g. overseeding dormant grasses, height of cut, amount of irrigation and fertilizer) can and should be evaluated for their long-term sustainability (cost versus benefit). When it comes to pest management and cool season grasses, a return to simple, time-honored maintenance practices might hold the key to greater sustainability.
Artificial turf is becoming a viable alternative to turfgrass for specific circumstances and applications.
New turfgrasses are regularly being developed through hybridization to enhance the positive traits and minimize the negative traits of common species and to make them better suited for golf course applications. The following characteristics can all be compared and considered in the selection of the turfgrasses for tees, fairways, greens, maintained rough, and native out-of-play areas:
density,
color,
leaf texture,
shade tolerance,
wear tolerance,
heat tolerance,
drought tolerance,
salinity tolerance,
disease resistance,
time to establish,
recuperative ability (including divot recovery), and
fertility and maintenance requirements.
The National Turfgrass Evaluation Program (NTEP) is an independent, non-profit research organization that evaluates and compares the cultivars of seventeen different turfgrass species based on color, density, resistance to diseases and insects, tolerance to heat, cold, drought and traffic. NTEP.org is an invaluable resource as the starting point in the turfgrass selection process.
Test plots of turfgrass cultivars
An experienced consulting agronomist will know which traits each of the cultivar candidates on the NTEP lists were bred for. The agronomist will use that knowledge, plus test results from the available irrigation water sources and topsoil, to determine the turfgrass species and cultivars that are most likely to possess the desired physical characteristics without requiring an unsustainable degree of maintenance.
One other characteristic to look for in fine fescues, tall fescues, and perennial ryegrass is the presence of fungal endophytes (designated as E+). An endophyte is a beneficial fungus that lives symbiotically within these turfgrass species and helps them to store and use water more efficiently, better withstand extreme heat and drought, and resist certain surface-feeding insects and fungal diseases. Many cultivars of fescue and ryegrass are now being bred with endophytes, which, under equal conditions, will require less water and fewer inputs (e.g. insecticide, fungicide) than the same turfgrass without the presence of endophytes.
Different Turfgrasses For Different Areas
When using a warm season species, it can make sense to select one single turfgrass species for all of the in-play areas and only vary the amount of irrigation and height of cut based on the location (e.g. tee vs fairway vs maintained rough). This can greatly simplify maintenance and make a golf course much more flexible if, for example, the superintendent wants to narrow or expand the fairways or aprons for tournament play. However, it’s more often the case that different highly specialized turfgrasses will be utilized for different areas of the golf course. As an example, greens and tees are the most intensively maintained areas of the golf course (in terms of irrigation, height of cut, rolling, aeration, topdressing, fertilizer, fungicide, and pesticide) and are usually grassed with the finest leafed cultivars that can tolerate a very low mowing height (typically highly-refined varieties of bentgrass in cool climates or Bermudagrass in warm climates).
Fairways, being slightly less intensively maintained, can accommodate cultivar(s) that are complimentary to the greens and tees turfgrasses but aren’t as refined (and can be less maintenance intensive (depending on the budget and expectations of the client)).
Maintained rough that is in-play is even less intensively maintained (and may or may not be irrigated) so an even less refined grass type can be specified for these areas that is different in color or texture to the fairways. However, care must be taken to select grasses for the maintained rough that can remain low and playable with a minimum of management required to control the height and density of the sward. Ultimately, turfgrasses for the maintained rough should be selected that will remain weed free, stable, and playable with little or no soil amendments, irrigation, or fertilizer.
Finally, native grasses and flora are often the most sustainable and cost-effective solution for native out-of-play areas. A pre-construction evaluation of the site and a survey of flora within the geographic area of the golf course will help determine the most desirable species that can thrive with a minimum of maintenance or attention.
Cool Season vs Warm Season Grasses
Cool season grasses are those turfgrasses that experience optimal growth conditions when the soil temperature is between 60 and 75° F (15.5 to 24° C). They perform best in cool and humid conditions found throughout Canada, the UK, Northern Europe, and more northerly Asian countries. In the United States, cool season grasses are commonly seen on golf courses in the Northeast, the Northern Midwest, and the Pacific Northwest. Cool season grasses can also thrive in the cool, arid conditions of the Midwestern and Western United States and Canada, as long as irrigation is available. These turfgrasses will start to struggle when soil temperatures regularly climb above 80° F (27° C). When the temperature drops below the optimal range, cool season grasses will not go dormant but growth and recovery will slow down significantly.
Species of cool season grasses that are most commonly grown on golf courses are:
creeping bentgrass (Agrostis stolonifera),
colonial bentgrass (Agrostis capillaris),
fine fescues (Festuca rubra), including:
Strong creeping red fescue (Festuca rubra ssp. rubra),
Slender creeping red fescue ((Festuca rubra ssp. littoralis),
Chewings fescue (Festuca rubra ssp. cummutata),
Sheep fescue (Festuca ovina),
Hard fescue (Festuca brevipila),
tall fescue (Festuca arundinacea),
Kentucky bluegrass (Poa pratensis), and
perennial ryegrass (Lolium perenne).
Warm season grasses grow best when the soil temperature is between 80 and 95° F (27 to 35° C). In humid areas, such as Southern Europe and the Southeastern and Gulf Coast of the United States, Mexico, Central America, and Southeastern Asia, the following warm season grasses can thrive for much of the year:
Bermudagrass (Cynodon dactylon),
Zoysiagrass (Zoysia),
St. Augustine (Stenotaphrum secundatum),
Bahiagrass (Paspalum), and
Centipedegrass (Eremochloa ophiuroides).
In arid regions, such as the Southwestern United States, Bermudagrass is most favored for its drought and heat tolerance.
When the soil temperature drops below the optimal range, warm season grasses will begin to go dormant and turn brown. This will usually not affect the turfgrass’s playing characteristics but superintendents often will overseed with a cool season grass (typically perennial ryegrass) to maintain a green color. Overseeding is most typically done on high-end private and resort golf courses where the player’s expectation is for lush and green turfgrass. Very heavy traffic can damage dormant turfgrass so that is also an important consideration in the decision whether or not to overseed (average to low levels of traffic will not cause lasting damage). It should also be noted that overseeding with cool season turfgrasses actually puts extra shade stress on the primary (warm season) turfgrasses and competes with them as temperatures begin to warm up in the spring, which is a downside to overseeding.
There is also a transition zone between northern and southern climates where it is generally too hot in the summer for cool season grasses and too cold in the winter for warm season grasses. The typical solution in this area is to overseed with a mix of cool and warm season grasses to maintain a green color and full density at different temperatures at different times of the year.
If very heavy traffic isn’t a concern, many golf course superintendents can forego overseeding and instead paint their dormant warm season grasses green to help satisfy golfer expectations. Painting rather than overseeding equates to savings on seed, water, fertilizer, plant protectants, and the time and labor of overseeding and additional mowing all winter. There is also much less down time for the golf course (a few days to paint versus several weeks for overseeding). Finally, the playing conditions on dormant warm season grasses are typically faster and firmer, which is often desirable.
Alternatively, some golf courses will forego both overseeding and painting and just accept the color and texture contrast that comes with dormant turfgrass. A side benefit of this is that undesirable invasive turfgrasses and weeds that are not dormant are very easy to find and eradicate (by showing up as spots of green in a sea of brown).
Ultimately, if heavy traffic isn’t a concern, the decision to overseed and keep the grass green and lush through dormancy (and cost, time, and effort that it entails) comes down to golfer expectations – which can be changed!
The Philadelphia Cricket Club St. Martins Course has bentgrass greens and Zoysiagrass fairways with Kentucky bluegrass rough – seen here in winter dormancy
Sodding vs Seeding vs Sprigging
Cool season grasses are usually seeded, with specific areas sodded (see below).
Warm season grasses are most often vegetatively established (sprigged), with specific areas sodded, however many Bermudagrass and Zoysiagrass cultivars are now available as seed.
In general, sprigs and sod will establish more quickly than seed but seed is preferable by almost every other measure:
Sprigs and sod are more expensive than seed (cost per acre),
Sprigs and sod cost more to transport as measured by money and carbon expenditure,
Sprigs and sod are riskier to transport (can die if not planted quickly enough),
Sprigs and sod are more easily contaminated by weeds and bugs because they come with soil,
Sprigs have to be flooded once they’re planted, requiring more water than seeds (which only need to be kept moist).
When seeding, hydroseeding is the best option because the mulch and tackifier that the seeds are mixed into holds the seeds in place until they are able to establish as well as holding moisture, which reduces the amount of water required to establish.
Sod for both cool season and warm season grasses is commonly used in the following areas that are most prone to erosion:
Ring around greens and tees
Green slopes and tee slopes
Ring around bunkers
Steep slopes
Ring around catch basins and manholes
Major drainage paths
Lake and channel banks
Sustainability in Grass Selection and Maintenance
Turfgrass science is an area where constant advances are being made in the furtherance of the sustainability of golf courses. Some examples:
Seashore Paspalum (a type of Bahiagrass) is extremely tolerant of salinity, enabling it to be grown with very poor-quality water (salty water, gray water, and treated effluent). The water that is used to irrigate the grass will then be naturally filtered as it infiltrates and returns to the water table.
New strains of Bermudagrass are being developed that are extremely drought tolerant and have an improved cold tolerance, allowing it to be planted farther north into the transition zone and resulting in much lower water usage.
With pest management and cool season grasses, however, a reevaluation of some more recently developed maintenance practices might hold the key to greater sustainability:
Historic and organic farming practices, such as Integrated Pest Management (IPM), are being more widely adopted by progressive golf course superintendents (or out of necessity), requiring fewer pesticides (and non-synthetic chemicals) and leading to greater biodiversity.
In northern climates, low-input fine fescues and creeping bentgrass were the dominant species on golf courses in the 19th and early 20th centuries. The wider use of irrigation and inorganic fertilizers in the middle of the 20th century (and calls from golfers for greener, more tightly mown turfgrasses) created conditions that often allowed annual bluegrass (Poa annua) to outcompete the fine fescues and creeping bentgrass. As a result, Poa annua has become the predominant turfgrass on most northern golf courses - despite the fact that it generally requires more irrigation, fungicide, herbicide, and fertilizer and is less desirable as a playing surface for a number of reasons. A growing call for a return to low-input turfgrasses is starting to bring the situation full-circle, as superintendents have begun to focus on low-tech maintenance practices (e.g. tree removal and shade management, improved drainage, less irrigation, less fertilizer, higher height of cut) to create and maintain conditions that discourage the growth of Poa annua and allow the fine fescues and creeping bentgrasses to thrive once again.
Mowing heights should be reconsidered for all turfgrasses. Tighter mowing places additional stress on turfgrass, making it more susceptible to weeds, pests, and disease and intensifies turf wear. As a result, the more tightly mown turfgrass will require more intensive maintenance, including increased application of fertilizers, pesticides, and herbicides, to remain healthy. Money, time, and energy can be saved, and turfgrass quality can be improved, by simply not cutting turfgrass as short, particularly on the greens, but also on tees and fairways. The primary challenge is to convince golfers to accept slower greens, which will likely have the added benefit of speeding the pace of play and making more pin locations available (see Step 13: Feature Construction Spotlight – Putting Greens for more detail).
Artificial Turf
Finally, artificial turf technology has advanced to the point where its playing characteristics are now comparable in many ways to natural grass. Artificial turf needs very little maintenance and it doesn’t require pesticides, herbicides, or water.
There are certainly still some drawbacks to artificial turf that must be taken into account:
It would be prohibitively expensive to install artificial turf for large-scale applications,
Artificial turf greens are less receptive to long shots than natural grass greens,
Artificial turf is a petroleum-based product that creates pollution and waste in the manufacturing process,
Artificial turf is not biodegradable (though it's notable that forward-thinking companies are finding more ways to repurpose old artificial turf for e.g. revetted bunker walls and streambanks),
Artificial turf retains significantly more heat than turfgrass, making it practically unplayable during the hottest days of summer,
Finally, fungus and algae can still be a problem on artificial turf without proper maintenance.
However, for tees and practice putting greens, and in areas where water is expensive or shade or wear is a constant problem, artificial turf can be a maintenance and water saver as an alternative to turfgrass.
Contact Sustain Golf for More Information!
We know many knowledgeable consulting agronomists and seed suppliers within the golf industry who are able to answer questions about turfgrass. We also have experience with artificial turf and can assist with the design and installation of an artificial turf tee or green. We would be happy to make recommendations or answer any questions that you might have about sustainable and accessible golf course design, construction, or maintenance. Visit www.SustainGolf.com or contact us at the following address for more information: Contact@SustainGolf.com.
The European Institute of Golf Course Architects (EIGCA), in partnership with the GEO Foundation, has developed a continuing professional development program for its members called Raising the Standard of Sustainable Golf Course Development, or RSSGCD. This is the industry’s only structured program in the world to specifically train golf course architects in sustainable golf course design, construction, and maintenance best practices. A Sustain Golf team member has attained Stage 3 of this rigorous program.
A Sustain Golf team member is also currently serving on the EIGCA’s Sustainability Committee and is a GEO Certified Accredited Sustainability Verifier.
We firmly believe that common sense sustainable design, construction, and maintenance practices are the keys to the long-term survival of the game of golf. We aspire to be on the leading edge of applying sustainability concepts to golf course design, construction, and maintenance.
We will spend every day for the duration of the project on-site and/or coordinating with all contractors, subcontractors and professional consultants to be sure that no opportunities are lost and that the best golf course for your property is realized.
Up Next:
Step 17 – Grassing, Landscaping, Grow-In, and Turf Nursery
Sustain Golf is a collaborative group of like-minded qualified golf course architects. We are also qualified and experienced as civil engineers, vertical architects, and project managers. We have the breadth and diversity of experience and knowledge to offer a full suite of golf course design and construction services, from first concept to opening day on your new or remodeled golf course.
References:
Dobie, Frank. Goodbye Poa annua, Hello Bentgrass. GCM Magazine, April 2020. Retrieved from https://www.gcmonline.com/course/environment/news/convert-poa-bentgrass-golf
Braun, Ross C., Aaron J. Patton, Eric Watkins, Paul L. Koch, Nicole P. Anderson, Stacy A. Bonos, Leah A. Brilman. Fine Fescues: A Review of the Species, Their Improvement, Production, Establishment, and Management. Crop Science, May/June 2020. Retrieved from https://acsess.onlinelibrary.wiley.com/doi/full/10.1002/csc2.20122.
Hurdzan, Dr. Michael J. Golf Course Architecture: Design, Construction & Restoration. Chelsea, MI: Sleeping Bear Press, 1996.
The Lawn Institute website. Retrieved from https://www.thelawninstitute.org/pages/education/types-of-grasses-and-species-selection/cool-and-warm-season-grasses/
ThoughtCo. What is ‘Overseeding’ on Golf Courses? Retrieved from https://www.thoughtco.com/what-is-overseeding-on-golf-courses-1560943
The National Turfgrass Evaluation Program (NTEP.org)
Photo Credits: Recreational Systems International, Matthew Schiffer, Google Earth
Peer Review:
Dr. Keith Duff, former UK government wildlife agency Chief Scientist, current Golf Environment Consultant
Rick Elyea, President, Elyea Agronomic Consulting
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