Key Takeaways

• Grooming, verticutting and vertigrooming are different practices with different goals. How they might fit into your maintenance program depends on what you are trying to accomplish and the resources available.
• Using the right equipment and setup is critical for success with any of these practices.
• A more aggressive setup is not necessarily better. Making gradual improvements in growth habit and surface organic matter content is less disruptive and often more effective.
• Collecting data on the benefits and disruption to playability associated with these practices can help you optimize your surface management program.
• These practices should be performed when turf is healthy and actively growing.
   

Grooming

When discussing surface management, grooming may be one of the first techniques that come to mind. Grooming is performed with very narrow blades on relatively close spacing. The goal is to modify plant architecture and promote a more uniform and upright growth habit with improved density. Grooming is performed regularly, usually two or three times per week, to make gradual improvements and maintain desired conditions. Grooming equipment is typically attached to mowers, which allows light grooming to be performed as the greens are mowed.

The limitation of grooming is the depth to which it can be performed. It is intended to remove laterally growing leaves, not large amounts of OM or soil. Here are some additional considerations to keep in mind:

• Grooming can be performed as often as daily when turf is healthy and not under stress.
• If lateral growth has not been managed well, start at the higher end of recommended grooming height and gradually work toward a lower depth as plant architecture improves. Turf that is groomed more frequently will not be damaged as much by deeper setups as turf that is groomed infrequently.
• Groomers are often set to approximately 10%-20% below the HOC. For example, if the HOC is 0.125 inches, then the groomers would be set at 0.112-0.100 inches. However, turf that is groomed multiple times per week can tolerate a more aggressive (lower) groomer setup.
• Grooming greens that are a blend of creeping bentgrass and Poa annua can provide a more uniform, upright growth habit between the two distinctly different species.
• When done properly, grooming produces little, if any, disruption to playability. The long-term benefits far outweigh any short-term disruption.
• The goal is to remove turf leaves and stems. If large amounts of sand or soil are being brought to the surface, you are verticutting, not grooming.
   

Verticutting

The goal of verticutting is to remove OM and soil from the upper portion of the putting green profile. This practice is typically performed two or three times per season. Verticutting reduces lateral growth as stolons and rhizomes are severed, although not as effectively as grooming or vertigrooming since verticutting is an infrequent practice. Verticutting is an aggressive and disruptive process that produces a large volume of debris to clean up.

There are two common approaches to verticutting putting greens – using triplex-mounted verticutting cassettes or standalone verticutting machines. In both cases, blade spacing is much wider than grooming and the blades are significantly thicker. Standalone machines are much more aggressive than triplex-mounted cassettes and typically have wider blades and spacing. They can also create deeper channels into the profile.

Make no mistake, the goal of verticutting is to break through the turf canopy and remove soil and thatch from the upper portion of the profile. The proper depth and frequency of this practice depends on the existing condition of the greens and the desired outcome. A general rule of thumb for aggressive verticutting is that the blade depth should not be greater than the spacing of the blades.

Greens with a problematic layer less than 1 inch deep are usually great candidates for verticutting. The layer can be caused by excessive OM content or the accumulation of an undesirable soil or sand. To break up and dilute such a layer as quickly as possible, some facilities will verticut and aerate during the same week. This also minimizes the disruption to play. Hollow-core aeration is typically performed first. After the cores are removed and holes are filled with sand, aggressive verticutting is performed. Performing this combination the other way around is not recommended because aerating over the top of recently verticut greens can be damaging if root mass and/or sod strength are weak.

Greens with layering issues deeper in the profile may be better suited for conventional hollow-core aeration than aggressive verticutting. Remember, the Achilles heel of verticutting is the shallow depth it is able to reach when compared to conventional core aeration. If there are deep layering issues and excessive OM near the surface, a combination of verticutting and core aeration may be the best option.

Vertigroominng

Vertigrooming is exactly what it sounds like – a combination of verticutting and grooming. To be honest, it is more like verticutting than grooming and many will probably say it is a variation of verticutting. If we are going to call it verticutting, let’s call it “light verticutting.” While vertigrooming may not be a technical term, it is worth using because with the ideal setup, benefits from both verticutting and grooming can be accomplished without a major disruption to the putting surface.

Vertigrooming typically uses regular verticutting blades that are not carbide-tipped, on a half-inch spacing. While the process is more aggressive than grooming, it still does not cause significant disruption to the playing surface. The intention is to manage grain and lateral growth, and also remove trace amounts of OM with each treatment. It is not a coincidence that this practice has been adopted at many courses with high-quality ultradwarf bermudagrass putting greens. For ultradwarf putting greens, this process is performed weekly in many cases and after topdressing there is little, if any, disruption to the putting surface.

Some may ask why regular blades are better than carbide-tipped blades for this application and there are two reasons. First, it is important to ask yourself if you are using the best tool for the job or the tool that will last longer. In most cases, wider carbide-tipped blades are used because they last longer, not because they are the best tool for the job. Secondly, if the goal is to reduce lateral growth and grain, then one must ask what fills the void after the larger carbide-tipped blades are used. Wide, laterally growing leaves will fill that void. In essence, you are promoting exactly what you set out to manage by using aggressive setups with carbide-tipped blades. When regular verticutting blades are used, lateral growth is reduced and the channels created are just large enough to incorporate sand into the canopy, but not so large that they promote more lateral regrowth. An ideal order of operations and additional considerations for vertigrooming are outlined below:

• Mow the putting green.
• Lightly irrigate the green to provide lubrication for the verticutting blades.
• Backtrack vertigrooming works best on bermudagrass greens. The first pass should be made in the most aggressive direction – i.e., down grain – and the second in the opposite direction on the same pass.
• Blow off the debris, if necessary.
• Mow the green again.
• There should be little, if any, disruption to the putting surface.
• Sand topdressing should be applied after vertigrooming.
• Any sort of verticutting should only be performed when the turf is healthy and actively growing.

Planning your program

Greens that haven’t been groomed or verticut on a regular basis will require a more conservative setup in the beginning. After several treatments, lateral growth should be greatly reduced and the setup can be made more aggressive if desired. If an ultra-aggressive setup is implemented on a green with excessive OM or uncontrolled lateral growth, then the level of damage to the surface will be greater than necessary. Oftentimes, increasing the frequency of light verticutting but maintaining a less aggressive setup will provide better results in this scenario.

When developing a plan for surface management, the goal should be light and frequent applications if possible. When vertigrooming is performed more frequently with a reasonable setup, it becomes less disruptive to the playing surface and cleanup is faster when compared to more-aggressive setups that are performed less frequently.

Realizing that “less disruptive” can be subjective, many courses are collecting putting green data to help quantify surface performance and the impact of various maintenance practices. The USGA’s new GS3 is a useful tool to quantify green speed, firmness, trueness and smoothness. It can provide objective data to guide surface management decisions and help you decide what setups are best for your facility and maintenance program.

OM content is something that the practices described in this article are designed to help manage. Regular soil testing is an important part of understanding the goals and impact of your OM management program. Keep in mind that different labs may sample and test for OM differently, which can make it difficult to interpret results from different labs. We recommend using the same lab for comparing OM content over time and the USGA has funded research to develop a standardized protocol for sampling and lab testing soil samples for OM content in the future.

Summary

Regardless of what species of turf you are growing on your greens, grooming, verticutting or vertigrooming all have the potential to improve the playing surface. Equipment selection, setup and frequency of application are all critical factors to make sure you are accomplishing your agronomic goals without causing unnecessary damage to the putting surface.