Page 14 - GM Fall 2025 flipbook

Figures 4a & 4b: Greens with higher OM levels tend to be softer, resulting in deeper ball marks. In contrast, firmer greens with minimal OM
often produce splattered ball marks, leaving little turf behind to repair.
•  Ball Marks: Softer greens with higher
OM levels produce deeper craters. OM
values above 8% will show deep ball
marks. On the other end ball marks that
splatter with almost no turf left to fix
could be an indicator of not enough OM.
This can be seen with OM at 5% or
lower. This must be interpreted with
caution, as the type of hole — such as
short par 3s with more approach shots
versus longer par 5s — can influence
how frequently and severely ball marks
occur. Looks for trends when it comes
to ball marks. A range of 5-8% usually
correlates with optimal ball marks. (see
Figure 4a and 4b)
•  Wear Tolerance: Low OM can lead to
thinning under traffic stress — especially
on small or shaded greens. This is seen
with OM less than 4%. This is not the
case on every property but a trend.
Think about what greens thin or do not
take the wear in the heat of the summer.
•  Scalping: Excess OM causes puffiness
and increases risk of scalping in humid
conditions. Topdressing and rolling can
help level surfaces and reduce this issue.
In my experience, OM above 10-12% can
scalp on slopes but this is not seen very
often.
By observing these indicators
throughout the season and correlating
them with OM levels, turf managers can
fine-tune their ideal OM targets.
3. Depth-Specific OM Management
•  0–2 cm is the most responsive to change and where OM varies the
most. Effective management here (via topdressing and verticutting)
can yield immediate results.
•  2–4 cm and 4–6 cm are more stable. Significant OM change at these
depths requires aggressive aeration to create sand channels that dilute
OM and promote deeper rooting.
•  Visual inspection of soil cores can help verify layering and guide aeration
strategies, especially when subsurface barriers are limiting water or
root movement.
4. Adjusting Based on OM
• Use past OM246 data and surface assessments to develop an annual plan.
•  Track sand application using a catch pan and keep records to correlate
OM change with inputs.
•  Adjust topdressing amounts based on OM accumulation rate and target
levels.
This approach creates a system that is both reactive and proactive
— addressing immediate issues while building toward long-term
consistency and playability across greens.
MANAGING OM TO YOUR ADVANTAGE
Organic matter is often treated like a problem to be solved — something
to reduce at all costs. However, OM also plays a key role in turf resilience.
By using OM246, turf managers can adopt a data-driven approach to
achieving consistent, resilient, and high-performing putting greens. The
key is not to eliminate it, but to manage it at a desired level.
OM246 gives turf managers a way to do exactly that: to measure
where OM exists, understand how it is changing, and build strategies
around reliable data to manage it. GM
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• CGSA • GreenMaster