The roller coaster continues with winter weather over much of the country. Record-low temperatures, extreme temperature fluctuations, heavy rain and icing events are troublesome for those managing turf. Grass in the Northeast region has already been exposed to below-zero temperatures, which in itself is usually not a major concern in late December or January. However, the rate and extent of the temperature fluctuation along with the presence of standing water or slush combined with extreme cold are very troublesome, and that is the concern with the latest freeze event impacting the region. This combination of weather events is the most worrisome to turf managers maintaining large populations of annual bluegrass and even low-cut perennial ryegrass. The concern to date is not ice encasement; rather, it is direct cold temperature kill or crown hydration injury.
It is likely too early to determine if any winter injury has occurred. Areas that have retained some snow cover may have been spared if the snow was able to buffer frigid temperatures at the surface. Golf facilities with enough staff available to remove standing water and slush from greens prior to the deep freeze can feel a bit more comfortable. The heavy winds that occurred as the temperatures began to drop seemed to evaporate at least some of the surface water to further improve prospects for turf survival. Greens covered with impermeable fabrics and insulating materials will also better withstand the temperature change and hydration. At greatest risk are low-pocketed, poorly-drained putting green and fairway areas dominated by annual bluegrass. It will also be a test for the newer, more cold-tolerant bermudagrasses that are fulfilling niche roles on Northeastern golf courses.
At this point there is little to do but wait it out. Forecasts call for another warming trend and that should make it possible to extract a few turf plugs from areas that are vulnerable or have a past of winter injury. Turf plugs can be cut out of the surface using a reciprocating saw, such as a Sawzall®, and chisel. Turf plugs are then brought indoors to assess its condition and see if turf greens up after a few days of exposure to warmer temperatures. For an excellent demonstration on how to sample turf for winterkill injury, please see the video Sampling Greens for Winterkill. A period of temperatures above freezing also provides an opportunity to expose and loosen some of the worst ice layers covering greens and other important playing areas. This too can be risky depending on the weather that follows but an extended forecast for above-freezing temperatures provides an opportunity to take action.
Things will become even more interesting moving forward. We must anticipate that turf that has already been subjected to multiple freeze/thaw cycles is depleting its stored energy reserves and thus its ability to tolerate colder temperatures and severe fluctuations decreases as well. We will update you with any news of turfgrass problems that may have resulted from this latest weather event or those we are likely to experience in the next eight to 10 weeks. I also hope to provide some ground temperature data recorded from soil sensors and data loggers in the field. Do not hesitate to contact our offices if you have any questions or concerns regarding the impacts of the ever-changing winter weather on your golf course. We wish all a successful season in the year ahead.
Source: Jim Skorulski (jskorulski@usga.org)
Information on the USGA’s Turf Advisory Service
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