COURSE CARE
Bring It On September 16, 2014 By David A. Oatis

The changing colors of the leaves are a highly visual reminder that it is time to prepare your greens for the upcoming winter.

The blue skies, low humidity, and cooler temperatures of fall do not harken memories of the cold winter months that lie ahead. However, turf managers everywhere need to consider the upcoming winter and begin to prepare the turf in advance. The first step is to begin raising cutting heights on putting greens. Many golfers enjoy faster putting green speeds, and the fall-induced physiological changes to turf make them much easier to achieve during this time of year. It is easy to get caught up in the “race for speed,” but doing so can affect the winter survival of your turf.

Think of the turfgrass leaves like solar panels. If turf leaves are kept in the shade their ability to capture energy will obviously be compromised. Low cutting heights effectively reduce the size of the solar panels and also will adversely affect their ability to capture energy. Why is energy so important? Plants now are storing carbohydrates for the winter; therefore, keeping cutting heights too low, too late in the fall, sends the plants into the winter in a weakened state. Turf that enters the winter weaker has a lower chance of survival. If we experience a mild winter, it may not matter. If we experience another winter like the last one, raising heights alone may not be enough; but, if you want to improve your turf’s chances of surviving this winter, and if you want to get it off to a quicker start next year, start raising cutting heights right now. Here are a few other things to do as well:

  • Raising putting green cutting heights by 0.005 inch a week, starting in early-mid September, will help. These slight increases will have a minimal impact on putting green speed.
  • Increasing sunlight penetration through tree work can have a huge impact on winter survival. Light penetration in the fall has a significant impact on the plant’s ability to store carbohydrates and harden off properly. Greens that are shaded in the winter experience slower melting and an increased potential for damaging freeze/thaw cycles. Winter shade, even when the turf is not growing, often translates to more winter injury.
  • Evaluate opportunities to improve surface and internal drainage. Deep aeration, drilling and filling, and installing internal drainage systems all are effective means of improving internal drainage. Improving drainage can impact summer performance as well as winter survival. Surface drainage can have a major impact on turf performance throughout the entire year. Poor surface drainage, frequently from collar dams, can trap water on green perimeters and greatly increase the potential for crown hydration injury. Multiple aerations followed by core removal and compaction can sometimes lower collars enough to improve surface drainage; but, if the damming effects are significant enough, sod removal followed by soil removal and regrading may be necessary.
  • Increase nitrogen fertility to promote healthy growth. Overfertilization in the fall can increase the potential for winter injury as well as snow mold diseases, but the turf should not be too lean and weak going into the winter either. Nitrogen and potassium fertilizer both are needed.

Pay even more attention to sunlight penetration if your greens experienced turf loss last year and now have more bentgrass in them. Creeping bentgrass has a much higher light requirement than annual bluegrass. Fortunately, the silver lining in the winter injury scenario is that many courses now have significantly more bentgrass in their greens than they did a year ago before the winter damage occurred. For courses with significantly more bentgrass in their greens, this is a great time to promote that grass more aggressively.

Source: Dave Oatis (doatis@usga.org)

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