When you think of winter preparation, visions of irrigation systems, air compressors, leaf-sweeping and vacation planning generally come to mind. And while the type and scope of winter preparations differ for courses in Minneapolis and Memphis, there is a certain routine that accompanies the fall season and the march toward winter.
The routine, however, may become too routine, resulting in minor (and not so minor) preparations or duties being forgotten or delayed. These omissions or delays may come back to haunt you because the results aren,t evident until the following spring when the turf doesn't come out of dormancy like it should.
Turf on golf courses is injured or lost from any number of causes, including winter diseases (snow molds), desiccation, low-temperature injury, ice-sheet injury and crown-hydration injury. Preventing these problems is sometimes impossible. But there are things you can do to reduce the potential for turf loss and to be better prepared to deal with it if it happens.
Consider the following list of programs, policies and problems as part of your overall winter preparation program. Some apply generally to all courses in the country, while others might be considered only for more Northern golf courses.
Preventing winter desiccation
Desiccation, or drying, is among the most common causes of winter turfgrass injury on Northern and Southern turf. Winter desiccation is most common where soils are frozen, on elevated sites, where relative humidity is low, where daytime air temperatures are above freezing and when sunny, windy conditions prevail for long periods.
Traffic -- especially golf car traffic -- on dormant, drought-stressed turf causes further desiccation injury. Irrigation obviously prevents this problem, but it's not an option when your irrigation system can't be drained easily and quickly. Spot watering, using frost-free irrigation lines or hauling water to crucial areas such as greens is necessary in many areas of the country.
If your course's turf areas are susceptible to winter desiccation, don't aerify late in the fall unless you fill holes with topdressing or unless the areas are able to heal before winter.
Some courses close sensitive greens and apply a 1/4-inch layer of topdressing to provide some insulation and to reduce evaporative water loss. Protective covers or blankets provide extremely effective insurance against winter desiccation, but they require close monitoring when disease conditions are optimal or when warm, sunny conditions create the potential for "baking" the covered turf.
Snow fences can be effective in areas where snow falls but is then quickly blown away. Some superintendents use pine boughs or needles as effective mulch coverings for exposed greens and tees. The best prevention for winter desiccation involves irrigation late into the fall (or into early winter), coupled with spot-watering of sensitive or crucial areas of the course throughout the winter and early spring.
Management of winter diseases
Among the most common -- and damaging -- of winter disease problems on cool-season turf are the snow molds. Gray snow mold, or Typhula blight (Typhula incarnata), and pink snow mold, or Fusarium patch (Microdochium nivale), occur under conditions of prolonged cold and snow cover. They can be especially severe when snow falls on unfrozen ground. Turf that is lush from overapplication of late-season nitrogen and that hasnt hardened off before snowfall is extremely susceptible to snow mold injury.
Reasonable late-season fertilization doesn't induce or heighten the severity of the snow mold diseases. In fact, a good late-season fertilization program encourages spring recovery of turf injured by snow mold.
Some superintendents remove early fall snow from greens if it's practical and if the ground hasn't frozen. This allows the ground to freeze and provides an opportunity to apply snow mold fungicides if it hasnt already been done. Similarly, you can remove slow-melting snow in the spring to enhance drainage and surface drying, thus reducing the potential for further snow mold disease.
It's important to remember that pink snow mold doesnt require snow cover to become active -- cool, wet conditions will suffice. Pink snow mold can be effectively prevented with PCNB, iprodione, propiconazole and triadimefon. Chlorothalonil in combination with these fungicides also provides good control. Gray snow mold is controlled with chloroneb, flutolanil, iprodione, propiconazole and triadimefon.
While snow mold isnt a concern on Southern bermudagrass, spring dead spot is. Although the symptoms of this disease manifest themselves in the spring, infection of the plant probably occurs in the preceding fall. You can decrease the severity of this disease by reducing or eliminating late-season nitrogen applications. In addition, proper thatch management and an application of fenarimol about 30 days before winter dormancy can reduce the severity of spring dead spot (2).
Mites often cause substantial loss of cool-season turf during late winter and early spring, which is often called winterkill. You can prevent or significantly reduce damage by clover mite, Banks grass mite, winter grain mite and brown wheat mite by some simple management practices.
First, because these mites often become active in the fall (when oversummering eggs hatch), it's prudent to scout areas prone to mite injury. Such areas include the south- or west-facing sides of structures (walls and buildings) or trees (especially spruces and other conifers) when clover mites are the problem.
Infestations of Banks grass mite, winter grain mite and brown wheat mite occur more generally throughout turf areas, but activity and damage is concentrated where turf is most prone to winter and early spring drought stress (south- or west-facing slopes of elevated tees and greens, and on bunker faces).
These mites cause little damage to cool-season turf in fall or early winter, but rapidly increase feeding and reproductive activity as weather becomes warmer in late winter and early spring. Because they're most active on drought-stressed turf, an aggressive fall/winter/early spring watering program largely reduces their populations and the degree of damage they cause. Once weather warms in the spring, most mite species become dormant (oversummering as eggs) or less active and dont cause turf injury.
Banks grass mite is less a winter problem in the South, but can be a troublesome summer pest on St. Augustinegrass and bermudagrass, causing injury that resembles heat or drought stress (2).
When irrigation doesn't appear effective in reducing mite activity or when damage becomes unacceptable, products containing chlorpyrifos, dicofol, bifenthrin or fluvalinate provide effective control. As always, check with your local university extension entomologist for help in identifying mites and for determining the best course of action in managing these pests.
Winter traffic program
Traffic on golf courses during the winter is a necessary evil for many superintendents. Golf car traffic can increase the loss of turf from winter desiccation, snow mold diseases, ice-sheet injury and crown-hydration injury.
Developing a comprehensive and strict golf car traffic policy can reduce the amount of winter injury while still allowing for player traffic. You must develop this plan -- in cooperation with the golf pro, club or facility manager and green committee -- early enough in the year so that it's not a surprise to the golfing community.
Appropriate communication to golfers via the club newsletter, locker room bulletin board postings and signage (for the course and cars) makes the transition from summer-traffic rules to winter-traffic rules occur more smoothly. The same type of decisions should be made with respect to other winter golf course traffic, including snowmobiles and cross-country skiing. The effectiveness of these programs -- or their deficiencies -- should be documented with photographs, allowing for sensible modification of traffic management programs in the next season.
Winter spike policy
Many Northern golf courses began instituting "no-spike" or "soft-spike" policies for winter play a number of years ago. This was necessary on courses that allowed winter play but didn't use temporary winter greens.
The value of "going spikeless" appeals more and more to golfers and clubs alike (superintendents need no convincing). The result has been a significant increase in the number of golf courses that are now spikeless year-round. If you aren't spikeless at your club yet, instituting a winter spikeless policy might allow for a smooth transition to a total metal-spike ban. The golf pro and club manager should need little convincing, considering the amount of damage caused to golf cars, walks, floors, carpeting and furniture. Of course, any policy of this sort requires the cooperative efforts of the superintendent and other appropriate course managers and officials.
Winter tees and greens
Developing a plan for winter play differs substantially for Southern and Northern courses. For Southern courses, this often involves the winter overseeding process -- a discussion that is beyond the scope of this article. For most Northern courses, however, decisions must be made regarding the amount and type of winter play to be encouraged.
Depending upon the area of the country, cut in temporary tees and greens sometime in mid-to-late September or early October. The tee areas should be level and located in sunny areas where snow won't accumulate.
Similarly, greens should be in a relatively flat and sunny location. It's wise, whether using regular or temporary greens, to have two to three extra holes cut in the green for winter rotation of the flagstick, as it's often difficult or impossible to cut cups during the winter. Conceal the extra holes with round pieces of artificial turf until the flagstick is rotated to that position.
Winter turf health monitoring
In late winter or early spring, some superintendents take cores of turf from areas of the course that appear to be suffering from winter-related injury. They place these cores in pots or trays in a sunny window (or a greenhouse, if available) to determine the extent of winter injury. Such simple testing allows you to get a handle on how much of a problem to expect when things begin to green up in the spring. If turf is thought to be dead and in need of renovation, you can develop a plan of attack to allow the crew to remedy the problem in an orderly and timely fashion.
Further, the ability to detect a potential problem before it becomes obvious to the golfer (and to communicate this concern to the green committee or golf course owner) demonstrates a high level of expertise on your part. Being able to predict that turf will die shows you understand the potentially devastating effects of winter conditions. This goes a long way in deflecting blame for turf loss from you and your crew -- as long as you have used all possible means to prevent the problem in the first place.
Soil testing and fertilization
Annual soil testing is considered by most superintendents to be an important part of their overall turfgrass management program. Yet its sometimes performed in a hurried, unorganized fashion, with little thought given to what areas of the course will be and what will be gained.
The most successful and revealing annual soil testing programs I've been involved with began with fall soil sampling. This is a great time to submit samples to testing labs because it's a more relaxed, slower time of the year for labs, and test results are generally returned in a more timely fashion.
Having test results over the winter allows you to analyze them more thoroughly and to consult with colleagues, consultants and university turf specialists regarding changes or refinements that might be undertaken in next year's fertilization program.
You also can contact fertilizer distributors, make product comparisons, take bids and make orders in an unhurried fashion. The more deliberate approach to soil testing and fertilizer programming makes you less apt to purchase impulsively (from the first salesperson through the door in the spring), or to make "autopilot" decisions (use what was used last year) because it has suddenly become so busy there's no time to study test reports and develop a fertilization program.
On Northern, cool-season golf courses, late-season fertilization encourages recovery of turf from the rigors of the golf season and from summer-related stresses. The use of quickly available nitrogen sources around the time of fall aerification enhances the effectiveness of the fertilizers and encourages rapid healing of aerification holes before winter. You are not looking to stimulate a lush turf, but rather a steady turf growth.
A late fall/early winter application of a more slowly available nitrogen source (natural organic or synthetic organic) will provide nitrogen for the following spring. This type of fertilization program encourages healthy turfgrass rooting, reduces the need for spring nitrogen applications and produces a stronger and more disease-resistant springtime turf plant.
You can determine actual ratios of N, P and K by using soil test reports, but you can't go wrong with a 1:1:1 ratio. Fall is a great time to apply any micronutrients that might be deficient; late-season iron applications provide excellent fall and winter color and may help prevent winter desiccation.
Late-season fertilization is not as easily recommended on Southern, warm-season grasses. While many superintendents apply nitrogen late in the season with apparent benefits, the practice can cause potential problems (1). Late-season applications of potassium are traditional on Southern bermudagrass, and iron applications are also becoming more popular.
While late-season nitrogen itself doesn't appear to cause winterkill, applications in conjunction with stress factors (drought, some cultural practices and possibly chemical use) may make the turf more susceptible to winter injury. Also, late-season nitrogen applications may predispose bermudagrass to spring dead spot.
Crown hydration injury and ice-sheet damage are important common causes of turf loss on the more Northern golf courses. While Poa annua is most susceptible to this type of damage, other turf species are not totally immune to injury.
When snow and ice accumulate in a thick layer over turf during the winter, the turf may suffocate as a result of poor oxygen exchange and a concentration of toxic gases under the ice layer. Melting and refreezing of water in late winter and spring can kill the crowns of turfgrass plants, which rapidly go from a green healthy appearance to brown in a matter of days. In both cases, the accumulation of water on fairways and greens is the cause of the problem.
Any efforts to enhance drainage -- both surface and subsurface -- helps prevent these types of winterkill. When significant thawing occurs, channeling of snow melt away from greens can prevent injury caused by subsequent freezing temperatures. The importance of adequate drainage in preventing winter injury cannot be overemphasized.
Pesticide, fertilizer and seed storage
Storage facilities for pesticides and fertilizers are constantly improving at golf courses throughout the country. However, many courses still lose valuable materials each year because of poor winter storage conditions. Materials that must be kept from freezing must be separated and stored away from those that can tolerate freezing. Turfgrass seed can tolerate freezing, but must be kept dry and in containers that keep out mice and other seed-damaging pests.
Fall is a great time to plan attendance at regional and national turfgrass conferences. Determine which conferences you will go to, as well as those that your assistants and other maintenance crew members should attend. Decide which optional/additional workshops should be attended -- and by whom. Send in the registration forms and fees early to avoid late charges and to ensure enrollment in any special seminars or classes. Then make any necessary travel arrangements, including hotel reservations.
Consider inviting the golf professional or club manager to attend all or part of a conference, giving them enough time to put it on their calendars. Schedule post-conference meetings with those who attended -- and those who did not -- as a means of sharing what was learned at the conference. Proper planning can make the winter a profitably educational experience for all members of the golf course crew.
Most superintendents have a well-defined prewinter routine. This list isn't meant to be comprehensive or detailed, but it may stimulate some thought in areas that haven't previously been considered.
1. Goatley Jr., M. 1994. Late-season fertilization of bermudagrass turf.
Golf Course Management 61:60-63.
2. Watschke, T., P. Dernoeden, and D. Shetlar. 1995. Managing turfgrass pests. Lewis Publishers, Boca Raton, Fla.
Tony Koski is an associate professor and an extension turfgrass specialist in the department of horticulture and landscape architecture at Colorado State University.