Got the Scalps? August 18, 2015 By Bob Vavrek, regional director, Central Region

This scalping occurred after several consecutive days of hot, humid weather and light, frequent rainfall. Be sure to reevaluate the effectiveness of your sand topdressing program when this occurs.

It happens just about every year…the greens look and putt great all spring and then the first extended period of hot, humid weather occurs. After a few days in the sauna, scattered patches of turf become soft and bloated. The mower catches the puffy surface just right and all the green tissue is shaved down to bare stems. You’ve been scalped.

Turf managers react to the scalping problem in different ways. Some raise the height of cut and others switch from grooved to solid front rollers, which essentially has a similar effect of slightly increasing the mowing height. Scalping that occurs on warm-season grasses during summer heat can indicate the need for a more aggressive maintenance, such as verticutting or grooming. Scalping injury to cool-season grasses during this period can indicate the need to back away from aggressive management practices that might further stress the turf and delay recovery.

A chronic scalping problem on either cool- or warm-season grasses can also indicate insufficient sand topdressing throughout the season. One of the important benefits of light, frequent topdressing is that the sand constantly buries and protects the crowns (growing points) of turf from the stress of mowing. The sand also helps dilute organic matter accumulation in the upper soil profile; and excessive organic matter (i.e. thatch) can also make turf prone to scalping during hot, humid weather. Not surprisingly, courses that make topdressing greens a high priority tend to have fewer episodes of scalping than those courses that rarely topdress their putting surfaces.

Scalping may be the wake-up call needed to step up the topdressing program. As a general rule of thumb for putting greens, try to apply 1 cu. ft. (100 lb.) of sand per 1000 sq. ft. of turf every 10 to 14 days whenever the grass is actively growing. Adjust the rate and frequency of topdressing according to the growth rate of the turf. Follow this advice and you will reap the additional benefits of topdressing greens, such as providing golfers a smooth roll and a firm, true surface.

Source: Bob Vavrek (


Central Region Agronomists:

Bob Vavrek, regional director –

John Daniels, agronomist –


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