After last year’s record-setting stretch of cold weather that swept through much of the southern part of the country, many courses suffered some level of winterkill. While there is no way to guarantee it won’t happen again, there are several steps that can be taken to significantly reduce the risk. As temperatures begin to drop, now is the time to start implementing these strategies if winterkill on bermudagrass is a concern at your facility.
- Increase the height of cut (HOC) on all fine turf surfaces. For fairways and tees the goal should be to have turf mowed at approximately 0.625-0.75 inch before it goes dormant. For ultradwarf putting greens that are not overseeded, consider increasing the height to approximately 0.150-0.165 inch. Remember, the height needs to be increased weeks prior to dormancy so the turf can reach the higher HOC.
- The best option for preventing winterkill on bermudagrass putting greens is to cover them with a permeable cover if low temperatures are forecast to fall below 15-20 degrees Fahrenheit. A threshold of 20 degrees provides more safety but will also increase the number of covering events.
- Proper soil moisture is also an important factor related to winterkill. Putting greens must stay warm enough to reduce the likelihood of winterkill, but the soil must also stay adequately hydrated. Consider applying a wetting agent prior to covering events to maintain uniform and adequate soil moisture.
- Trees can significantly increase the risk for winterkill on bermudagrass. Winter shade and tree roots that outcompete turf for water and nutrients are both issues that can contribute to winter injury. A secondary problem occurs when trees located close to entry and exit points around greens and tees concentrate traffic. Shade, tree roots and concentrated traffic all increase the risk for winterkill. If trees have contributed to problems in the past, they will continue to do so until they are removed.
- It is important to manage cart traffic while bermudagrass is dormant. Concentrated traffic can easily damage turf at a time of year where it has little to no recuperative ability. This is especially important if single cart riders are common.
- Limit fall nitrogen fertility. Dormancy is a natural mechanism that helps turf defend itself against winterkill. Promoting luxuriant growth during late fall or winter can increase susceptibility to winter injury.
Most facilities have successfully recovered from whatever winterkill was experienced last winter. This process can be time consuming, disruptive to the golf calendar and expensive. Several of the steps outlined above also come at a cost and may temporarily impact course conditioning, but a slight disruption during the winter is much better than months of recovery during the peak golf season.
Central Region Agronomists:
Paul Jacobs, agronomist – pjacobs@usga.org
Zach Nicoludis, agronomist – znicoludis@usga.org