Most golf courses in New England, upstate New York, and Eastern Canada remain covered in deep snow despite some rain and warmer weather that occurred this week. Recent storms have also blanketed southern parts of the region with snow. The deep, insulating snow pack has been beneficial for protecting grass from cold temperatures, but – like most in the Boston area will attest – there can be too much of a good thing. Those who have had ice on greens since January are justifiably nervous as ice cover now has lasted well over the 40 day mark. Several managers who have pulled samples from ice-covered greens in February (around 35 days ice cover) indicated that they detected the fermentation odor associated with anaerobic conditions and anoxia. Turf samples pulled from these areas were incubated and there is evidence that some injury may have occurred.
The condition of turfgrass plants growing in low-oxygen environments deteriorates over time. Part of the deterioration process involves the loss of stored carbohydrates that plants use to prevent cells from freezing. Low-oxygen environments most severely impact annual bluegrass health. Thus, those that manage annual bluegrass are faced with a difficult decision – remove the snow and ice and risk physical injury to playing surfaces and plant damage from exposure to colder temperatures; or allow the ice layer to remain and subject the plants to further deterioration and potential injury in the weeks ahead. It is not an enviable position to be in as the final weeks of winter approach. Fortunately, creeping bentgrass is better able to tolerate the impacts of anoxia while maintaining greater tolerance to colder temperatures. The following are some thoughts regarding snow and ice and the late winter season:
- Check the green surfaces. If no ice layer is present, allow the snow to melt naturally. Expediting snow removal should not be necessary and may actually create more problems should the cold weather pattern continue. Roads can be cleared to more easily access green complexes and some smaller paths across greens can be opened to help water drain when the thaw begins.
- Check for anoxic conditions below impermeable covers or where surfaces have been encased in ice. Use a chisel and hole saw to cut or break through the ice layer. A sickly, sweet, fermenting smell will indicate there are anoxic conditions. Anoxic conditions does not mean the grass is dead, but plants will likely be compromised or weak and more vulnerable to cold temperature and freeze thaw cycles in the weeks ahead. A grass plug can be extracted and incubated indoors to check its condition.
- Annual bluegrass greens that are anoxic and have been under ice for 40-60 days are at the greatest risk of damage at this point and some action may be needed to get air to the turf. It is always best to work with the weather rather than against it, so it makes sense to wait until there is a favorable forecast before removing snow and ice. Several golf courses were able to successfully clear greens of snow and ice in past weeks, but were careful to blow snow back over the exposed surfaces as soon as the ice layer was eliminated. This strategy may be effective if you have workable snow and available resources to complete the process.
- Use larger, tractor-driven equipment to make paths to greens. However, clearing greens with smaller snow blowers is preferred. Even greens with ice layers are not always able to support the weight of heavy equipment. If the use of large equipment is necessary use caution. Make sure snow is cleared far enough away from greens that water from melting snow does not flow back on putting green surfaces.
- Once the ice is exposed, darkening agents can be used on exposed sites to hasten melting. On more shaded sites a greens aerator or dethatching machine can be used to chip away or facture ice if necessary. Creating channels through the ice or collar dams may be necessary for surface water drainage as ice melts.
- Managers utilizing impermeable covers face similar snow-removal decisions especially if an ice layer is present above the covers and anoxic conditions are detected. Otherwise, the snow pack can be left in place until natural thaw begins.
February 2015 will leave a long-lasting mark for record levels of snow and cold temperatures. Ironically, it may not be the February weather that impacts golf courses as much as the less-memorable January weather or the future weather during the transition into spring. Good luck and feel free to contact your USGA Green Section agronomist if you would like to further discuss your situation and available management options.
Source: Jim Skorulski(firstname.lastname@example.org)