Wide Swings Are Bad Things January 19, 2017 By Bob Vavrek, regional director, Central Region

Sometimes an extreme, rapid drop in temperature across waterlogged turf can kill grass just as surely as a prolonged period of dense ice cover.

Weather patterns during the latter half of 2016 created stressful conditions for turf at golf courses throughout the Central Region and there was no letup for the holidays. A steady drop in temperatures during mid to late fall followed by consistent snow cover is ideal for preparing cool-season turf for winter hibernation. Unfortunately, several extreme temperature swings occurred during the middle of December – lows of zero degrees Fahrenheit preceded a rapid, wet warmup into the 50s and 60s that was followed by another cold snap. Those with cool-season turf could do little but wonder if the weather had killed or weakened grasses – e.g., Poa annua or perennial ryegrass – that have little tolerance for rapid freeze and thaw cycles. Those with warm-season turf were scrambling to cover and insulate bermudagrass greens when the frigid air moved south, plunging deep into the heart of Texas.

The good news is that cool-season turf has the greatest cold tolerance during early winter, so stressful weather patterns are far less likely to cause turf injury during December than during March. However, injury from cold temperatures or crown hydration is more difficult to predict than injury caused by long periods of ice cover. Refer to the article, “Winterkill – Causes and Prevention” for more detailed information regarding turfgrass cold tolerance and the processes of hardening and dehardening.

Are you wondering if Santa delivered winter injury to your golf course? For peace of mind, it never hurts to take a few turf samples from areas that have a history of winter injury and see if they green up under grow lights. The short webcast, “Sampling Greens for Winterkill” describes a simple procedure for collecting turf samples from frozen soil and testing them for winter injury.

We have experienced a rocky start to the winter of 2017; let's hope for a blanket of snow and consistent, seasonable temperatures until spring.


Central Region Agronomists:

Bob Vavrek, regional director –

John Daniels, agronomist –

Zach Nicoludis, agronomist –

Information on the USGA’s Course Consulting Service 

Contact the Green Section Staff

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