The type of ball mark generated when a golf ball strikes a putting green provides valuable insight into surface performance and how well the agronomic program is working. Obviously, saturated conditions will increase ball mark severity and greens with excessive organic matter are also more vulnerable to ripping, tearing and exploding ball marks. But what about greens that feel firm and measure firm, but still have severe ball marks?
If bad ball marks are being generated on an otherwise firm green, there is a surface strength issue. Here are just some of the factors that can create a weak putting surface:
- Too little organic matter limits the resiliency of a putting surface and increases the likelihood of deeper ball marks. Chasing a low organic matter percentage is common, but the reality is some organic matter is needed for surface strength.
- Cultural management practices can also temporarily impact surface strength. Of course, cultural practices like aeration need to be performed, but when and how they are performed can create conditions that exacerbate ball marks, at least temporarily.
- Poor growing environments create weaker, more-receptive putting surfaces. It is not a coincidence that ball marks are more pronounced and golfers can hold more of their shots on greens located in poor growing environments.
- Heavy traffic, whether from golfers or maintenance equipment, can weaken the surface and cause – you guessed it – bad ball marks. Traffic may negatively affect the entire green or only specific areas. For example, if bunkers restrict where golfers enter and exit a green, isolated sections of weaker turf may develop because of the concentrated foot traffic.
- The turfgrass species on a green also plays a role in ball mark severity. If we were to compare ball marks on well-maintained creeping bentgrass, Poa annua and ultradwarf bermudagrass greens, ball marks would be more pronounced on creeping bentgrass while only a small dent or bruise would be created on the Poa annua and ultradwarf greens. This is not to say that creeping bentgrass cannot deliver a firm, resilient surface, but of these three turfgrasses it typically has a lower surface strength.
USGA agronomists have started working with a tool called a shear-strength tester to measure surface strength and develop a better understanding of its role in putting green performance. In addition to confirming issues like those mentioned above, there is potential for this tool to benchmark surface strength on new greens and determine when they can be put into play. However, more data still needs to be collected. For more insight on putting green surface strength, reach out to your regional USGA agronomist.
Central Region Agronomists:
Zach Nicoludis, regional director – email@example.com
Paul Jacobs, agronomist – firstname.lastname@example.org
Information on the USGA’s Course Consulting Service
Contact the Green Section Staff