Beyond Cultivation

There are tools and techniques available to the golf course superintendent to improve overall turf quality and playing conditions. The most familiar of these are forms of cultivation.

Cultivation, as it applies to turf, is working the soil and/or thatch layer through various means without permanent damage to the turf. The result is an improvement in overall turf health. Cultivation includes core and solid tine aeration, slicing, spiking and verticutting. These activities involve some disturbance to the soil/thatch layer.

Often the quest to provide the best putting surfaces possible carries the golf course superintendent into innovative processes that expand the limits of what can be achieved. This is where the evolution of grooming and brushing has had an ongoing impact on the highest quality turf. Grooming and brushing are both less invasive than verticutting and share the goal to encourage vertical growth in the plant. Let’s examine the concepts and potential benefits of grooming and brushing and see if they may be the perfect addition to your program.

Grooming reels are available from most of the primary equipment companies and while they may differ slightly all focus on the objective to mechanically remove excess leaf tissue to encourage a more vertical growth habit. Grooming should focus on impacting the parts of the plant above the soil line in contrast to verticutting, which removes organic matter and tissues through the turf canopy and into the soil at a desired depth.

What actually occurs during the grooming process is that a series of light weight vertical blades (thin kerf) reaches down below the actual height of cut to remove horizontal runners/leaf blades and other organic matter. These vertical blades can be adjusted to various spacing usually ranging from .250 inches to .500 inches, depending on how aggressive you want the grooming action to be on the turf. Remember, when setting the depth for grooming a general rule of thumb is to be at or slightly below the height of cut and never exceed 10 percent below the height of cut.

The benefits of a regular grooming program include less graining, increased ball roll (green speed), improved water penetration, improved microbial activity, more efficient soil gas exchange, drier turf canopy, changes in the growth point of the new turf closer to the true crown and more vertical with time. These combined benefits also allow the turf to be healthier and more resistant to diseases and other common cumulative stresses.

However, be cautious during times of heavy stress on the turf and be sure the physical stresses of grooming though less than verticutting have been well thought out. Try to plan a grooming schedule that considers turf type (cool or warm season), turf use (green, tee, etc) upcoming events, topdressing and spray schedule and of course ultimately the optimum health of the turf are being considered.

Brushing is another solid addition to your agronomic programs. Brushing and grooming produce similar results through two physically diverse approaches.

Brushes were the original way to remove leaf blades, reduce grain and increase vertical growth habit. These early efforts were usually self-fabricated front-mounted brushes that stood up the leaf blade prior to the reel making the cut. The results were generally good and affordable. The brush bristles were either stiff or soft and both worked well in given conditions.

When making brush or bristle choices the stiff bristle brushes are perfect for periods of lush active growth while a soft bristle brush is better for transitional periods prior to the arrival of summer or winter turf stresses. There has been a renewed interest in brushing as new turf grass cultivars have been introduced with mowing heights as low as a 1/16 inch mandating every technique be used to achieve the desired bench marks in turf quality and playability. Thus, innovation came to the process of brushing and highly effective rotating brushes were introduced.

The benefits of this type of brushing include prominent stripping of the surface, less bruising and physical damage than groomers, removal of Poa seed heads, reducing grain and increased ball roll.

There is an art to adjusting the engagement depth of rotating brushes and it relates to a risk/reward aptitude from the superintendent. However, there are a few general guidelines that can help you dial in a brushing program to exceed players’ expectations.

In brushing, like all procedures that impact turf, start with the lightest settings and work progressively forward until you find the desired result. It is a good idea to raise the mowing height at least 10,000th of an inch for the initial brushing and then drop 5,000th of an inch every other day until you reach the desired results.

There are a few guide lines for setting the brush height depending on how dense the turf is, you should set the brush height at the height of cut if the turf is very dense adjusting lower as positive results are generated and adjusting higher if the results are negative. Always set your brush height at the high side on the brushes, not the short or low side.

The benefits of grooming and brushing are well documented, but there are some things to consider to ensure success within these programs. When scheduled properly, grooming/brushing can have a positive impact on top dressing, spraying and applying granular products by allowing better canopy penetration and soil contact. But it can also have a negative impact if done too soon before/after these applications through increased plant stress or removal of material.

My long-time friend Jim Stuart, the award-winning lead equipment tech at the Stone Mountain Golf Club near Atlanta, says: “Groomers and rotating brushes are precision pieces of engineering and in order to perform up to the standard they must be properly set up and monitored so that all of the moving parts are functioning at peak performance. Nothing should be left to chance this includes the speed of the machine, RPM ratio (1.75:1 for example) and even operator training. It does not matter whether the grooming/brushing is being done with a walking mower, triplex or larger mower; factory specified or locally fabricated equipment, the attention to detail and awareness of plant responses are critical to success.”

Grooming and brushing reward those who can customize these programs to complement their base agronomic goals, finding the combination of function, set up, execution and adjustment.

Anthony L. Williams, CGCS, CGM, is a retired Georgia superintendent and a frequent GCI contributor.