By Chengyan Yue, Professor, Department of Applied Economics and Department of Horticultural Science, University of Minnesota; Uma Parasuram, PhD student, Department of Applied Economics, University of Minnesota; and Eric Watkins, Professor, Department of Horticultural Science, University of Minnesota 

The northern regions of the United States and Canada are known for their brutal winter climates, and golf courses in these areas experience a unique challenge: winter injuries. Winterkill is the term used to describe the damage inflicted upon turfgrass due to extreme cold, and it's a phenomenon that can have substantial financial impacts. Winterkill affects golf course finances in three primary ways: pre-winter maintenance costs, post-winter repair expenses, and revenue losses due to delayed openings. A typical golf season in the northern U.S. spans approximately seven months, from April to late October (Figure 1). Each day of delay in opening can lead to revenue losses of up to $7,900 per golf course (SRI International, 2006). In 2022, a survey was conducted among golf course superintendents in the northern U.S. and Canada. This survey collected data on the causes of winter injuries, the extent of damage across the golf course, and various management practices employed.

Preliminary findings from the survey show that winterkill has caused turf damage to ~45% of the surveyed golf courses in USA and ~ 51% in Canada. The reasons behind these damages, as reported by the golf course superintendent, are multifaceted, encompassing differences in grass types, varying management practices between public and private courses, weather fluctuations, and other golf course factors. For the courses that experienced winter injury, opening was delayed on average from 2-4 weeks. Annual bluegrass (Poa annua) and creeping bentgrass (Agrostis stolonifera) were most often reported as sustaining some form of winter damage, which is unsurprising since these grasses are very common on golf greens throughout the surveyed regions (Figures 2 and 3). 

The average cost of repairs and revenue loss due to delayed opening in a year with normal winter injuries for the surveyed courses was about $145,000. In years with considerable (more than normal) winter injuries, the total loss per golf course can go up to $186,000. To mitigate these damages, golf course superintendents employ a combination of practices. The most widely used practices reported (Figures 4 and 5) were applying snow mold fungicides (87%) or plant protectants (60%), aerifying in late fall (57%), topdressing (57%), stopping the use of plant growth regulators in September (51%), building carbohydrate reserves through management practices (49%), and applying wetting agents (48%). Mowing heights are also adjusted, with 67% of superintendents raising them in late fall.

Continued analysis of the survey data will help us provide data that can be used by golf course management decision makers when determining costs and benefits for various management practices. Concurrently, turfgrass management experts on our WinterTurf team are conducting field projects to determine the effectiveness of some of the reported management practices that are currently in use to reduce winter injury risk.

Reference

SRI International (2006). The Minnesota Golf Economy 2006.  https://www.mngolf.org/res/EconomicImpactStudy2006Summary_3.pdf