COURSE CARE
The Poor Man’s Winter Cover October 16, 2011 By Bob Vavrek

A moderately heavy application of sand just before the snow arrives can help protect turf from wind desiccation. The keys to success are (1) to topdress when the greens are firm enough to accommodate the equipment without rutting, and (2) to apply just the right amount of sand to bury the crowns of the plants without smothering the turf.  

Days are getting shorter and morning frost delays are getting longer.  Mowing transitions into leaf removal and it’s time to think about how the course will be put to bed for the winter.

Do I cover or not cover the greens?  What kind of cover is best, or do I need different covers for different greens?  Can I afford covers?  Do I have enough labor to install and remove covers efficiently?  When do I apply the cover and when do I remove the cover?  Do I have adequate space to store the covers?  What do I tell the boss if winterkill still occurs under the cover?  There are no simple, clear-cut answers to these questions, and a short Regional Update is not the venue to discuss or debate the issue of covering greens.

Of course, the debate ends instantly if your golf course simply cannot afford covers, but there is still an economical option to consider for providing a basic level of winter protection to greens.  A moderately heavy application of sand topdressing to the putting surfaces during late fall/early winter after snow mold fungicides are applied will provide a fair amount of protection from wind desiccation during an open winter.   Follow a few basic topdressing rules and there is significant reward for little risk at minimal cost.

The two biggest mistakes are burying the greens in way too much sand and attempting to apply sand with heavy equipment when the greens are soft and wet.  What is the right amount of sand?  It’s difficult to make a specific recommendation because greens at different courses go into winter at different mowing heights and the physical properties of sand vary between suppliers.  A rate of sand that may smother a green being mowed at 1/10” of cut may be just right for a green going into winter at 5/32”.  Shame on those going into winter at 1/10” but that is a topic to discuss some other time.

In general, most courses apply too little sand to greens during the season, partly due to complaints from golfers who don’t like sand on the ball and equipment managers who don’t like dull mowers.  As a result, it will be difficult for some superintendents to apply any more than a dusting to greens before winter, basically wasting their time.  A good rule of thumb for standard topdressing during the summer is to apply about 1 cu. ft. of sand per 1000 sq. ft. of putting surface (approximately 100 lbs. of sand for an average 5K sq. ft. green) every 10 to 14 days, depending on how fast the greens are growing.  This would be a good place to start when considering a late-season topdressing application.  Apply no less than the summertime standard and more if the greens go into winter a bit shaggy.

On the other hand, don’t bury the greens in sand.  Courses that make this mistake find they spend a considerable amount of time removing excess sand from the greens before the turf can be mowed during the following spring.  The process of removing sand can cause a great deal of abrasion to the semi-dormant turf, already stressed by ice cover or thaw/freeze injury.  Moreover, an extra-heavy blanket of sand can be partially displaced by rain or melting ice/snow.  Greens with severe contours will be affected the most.  Small ridges of sand accumulation will impede surface drainage and smother the turf.  Make sure there is enough sand to bury the crowns of the turf and still see the blades of grass poking up through the topdressing. 

It’s better not to topdress at all than to topdress when the greens are wet and soft.  Shallow ruts made by tires of topdressing equipment are often the areas that hold a little water during a thaw and end up being the sites affected most by crown hydration.  Dead Poa annua along the tire tracks of topdressing units is seen on a number of courses every spring, usually the result of applying sand to a soft green.  Try loading the topdresser with just enough sand for one green, or a part of one green to reduce the overall weight of the equipment.

Furthermore, late fall topdressing serves another very useful purpose, even when consistent heavy snow cover protects turf from winter stress.  The sand will slowly be assimilated into the upper regionalUpdateContent zone the following spring and help dilute organic matter accumulation during a time when greens are typically too soft to accommodate heavy equipment.   The majority of courses seen on TAS visits could use more sand in the upper regionalUpdateContent zone, and late fall topdressing can help achieve this goal without causing dull mowers or annoyance to play. 

Source:  Bob Vavrek, rvavrek@usga.org or 262-797-8743