COURSE CARE
There Is No Time Like The Present October 20, 2010 By Bob Vavrek

Topdressing and core cultivation were neglected, and an undesirable layer of thatch developed in the upper regionalUpdateContent zone of this green. Thatchy greens remain soft and spongy for long periods of time after irrigation or rainfall, and golfers will notice deep, pitted ball marks. To make matters worse, soft, wet greens are highly susceptible to a myriad of agronomic problems, such as scalping, wet wilt and Poa annua encroachment.  

Countless courses have put cultivation and topdressing programs for greens on the back burner during the past few years.  No time, no labor, no money, inadequate equipment, surface disruption and golfer dissatisfaction are just some of the reasons used to justify the failure to core and sand greens at appropriate intervals.  As reasons go, they aren’t all that bad, considering the sluggish golf economy.

What is bad is the dense layer of spongy organic matter accumulation that quickly developed when these basic maintenance practices were neglected.  Up until this year, the past several summers have been very mild. Thatchy greens usually perform quite well as long as the weather cooperates.  But, as mentioned in a recent North-Central update, the weather this summer was exceptionally stressful, and numerous courses had to “pay the piper” with respect to severe turf losses on thatchy greens caused by heat stress, regionalUpdateContent decline, disease activity and wet wilt.

Superintendents are making firm resolutions to address their thatch problems on greens, vowing to aggressively topdress and cultivate greens next season; but why wait when there is still a great opportunity to jump-start a thatch management program this fall?  Simply employ the tried and true practice of topdressing the greens with a moderately heavy layer of sand after putting surfaces are treated with fungicides for snow mold. 

Late fall topdressing is the poor man’s cover that provides turf fairly good protection from wind desiccation.  The often-overlooked benefit of sanding greens before winter is thatch management.  Root growth on greens will continue through fall and into winter until the ground freezes.  The sand that buffers turf from the damaging effects of winter wind also will help dilute the late fall/early spring organic matter that is recycled into the greens.   In effect, pre-winter topdressing provides an effective bridge between the last coring or topdressing operation of fall, and the initial coring or topdressing operation of the following spring.

Just how much sand to apply before winter will vary from course to course.  Greens maintained at higher heights of cut can accommodate more sand than greens at short heights of  cut.  When in doubt, it makes more sense to err on the light side of late fall topdressing.  A few courses new to this practice made the mistake of burying the greens in sand to the point where the green was white.  Rain and melting snow shifted the sand during the winter, which smothered the localized areas of the putting surface.  Even when injury does not occur, a green buried in topdressing will need to have a considerable amount of sand removed from the turf prior to the first mowing operation, or those reels that were meticulously ground and sharpened over the winter will be trashed within a few hours of use. 

On the other hand, applying a few walk-behind spinner spreader loads of sand to a green in November won’t provide much benefit other than a little exercise for the crew.   The right amount of sand is somewhere between standard, light midsummer topdressing, and the heavy load of sand applied to greens to fill holes after core cultivation.  You should always be able to see green blades of grass sticking up through the sand. 

Once you make the commitment to more coring and topdressing, there is no time like the present to get started; so, give late fall topdressing a try if excess thatch accumulation has become a problem.

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