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Can't See 'Em July 6, 2018 By Larry Gilhuly, agronomist, West Region

The impact of golfers’ feet near a hole can have a dramatic impact on ball roll, as illustrated by the depression created a few inches away from this hole.

Next time you watch golf broadcasts, listen carefully for a common sentiment concerning Poa annua putting greens. Although not always said the same way, the sentiment is based on the claim that Poa annua greens grow quickly and become very bumpy as the day progresses. In many cases, seedheads are also credited as causing major playability issues on Poa annua putting surfaces. It’s true that Poa annua putting greens may experience uneven growth because often they have many different biotypes of Poa annua. It’s also true that seedheads can be an issue on Poa annua putting greens during certain times of the year. Fortunately, growth regulators have greatly reduced these two issues. So, are there other overlooked factors at play that cause golf balls to bounce off line? The answer is yes. The following three issues in particular are caused by golfers on all types of putting greens, not just those with Poa annua.

The first and most common issue affecting the smoothness of any putting surface, including those with warm-season grasses, is footprints. Footprints are especially problematic when the upper soil profile has excess moisture such as after a heavy rain. To see the impact footprints can have on putting green smoothness go to any golf facility after a day when 150-200 golfers have played the course. The key is to go either very early the next day – i.e., before the putting greens are mowed – or as the sun goes down at the end of the day. It is truly startling to see the impact that the indentations from golfers’ feet can have on ball roll. Roll a ball at the hole and you will see the increasing effects of foot traffic as the ball gets closer to the hole. Also, note how the ball often moves away from the hole as areas around it are depressed by heavy traffic. While Poa annua seedheads can certainly reduce overall smoothness, their impact pales in comparison to the disruption caused by golfers’ feet.

The second often-overlooked factor that impacts putting green smoothness is ball marks. When improperly fixed, ball marks will definitely impact ball roll. However, what about when putting greens are firm and ball marks cannot be seen? Shallow, unrepaired ball marks can easily make a ball bounce into the air, but what do we hear from the announcer? Typically, their commentary focuses on seedheads and the variable growth rate of Poa annua, neither of which usually make a golf ball go airborne.

The final easy-to-miss impact that golfers can have on surface smoothness comes from the small stones that they sometimes splash onto putting surfaces from greenside bunkers. In some cases, even a small pebble can impact the roll of a golf ball. This issue becomes more problematic as the day progresses and more bunker shots are played. It can also be difficult to recognize the presence of small pebbles when putting greens are stressed and go off-color. Again, go to any golf course late in the day after extensive play. Stones that simply are not visible during the day can cast impressive shadows during the evening.

So, the next time you watch a golf broadcast or play your local golf course, remember that Poa annua can create some of the best and smoothest putting surfaces. However, there are several factors in play that truly impact overall putting green smoothness as the day proceeds, regardless of grass type. The problem is, you often can't see 'em.


West Region Agronomists:

Patrick J. Gross, regional director –

Larry W. Gilhuly, agronomist –

Brian S. Whitlark, agronomist –

Information on the USGA’s Course Consulting Service 

Contact the Green Section Staff

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