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Bah, humbug

C62291821dac0dd5b7ef3b72a30cd137?s=47 Micah Woods
November 06, 2019

Bah, humbug

In my final presentation at the Oregon GCSA fall meeting, I asked if it is possible to maintain a high performing putting surface without core aeration? Perhaps, but under what conditions? And if no coring is done, how much sand topdressing would be required? Case studies and data from golf courses around the world are discussed in this seminar, in which I make the case that it might be possible, and not just humbug.

I used to recommend, pretty consistently, that high performance turfgrass surfaces should have 20% of the surface area removed each year and that sand topdressing be applied at 12 to 15 mm per year. I don’t make those recommendations any more, because I’ve seen so many high performing surfaces, in a range of climates, that are produced with a lot less disruption and sand addition.

I’ll talked about how to make this a site specific decision, based on current and desired conditions at a particular site. For more about this, and to follow the development of my thinking about this topic over the past five years, see the organic matter & OM246 tags at


Micah Woods

November 06, 2019


  1. Bah, Humbug Micah Woods November 6, 2019 Chief Scientist Asian

    Turfgrass Center
  2. How much coring and sand topdressing is really necessary?

  3. What do we want? • 100% grass cover • some

    expectation of that continuing • ball roll • ball bounce
  4. Management of organic matter Increase growth & OM • fertilizer

    (N) • irrigation Reduce OM • sand topdressing • core aerification • solid tine aerification • verticutting
  5. What I used to do

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  8. “the underlying problem is often excessive organic matter just beneath

    the putting surface. Core aeration, verticutting, and topdressing are the primary agronomic practices used to manage organic matter, but they are disliked by most golfers.” Moeller & Lowe, 2016
  9. “There are many agronomic programs that influence the playability and

    health of putting greens, but organic matter management is arguably the most important.” Moeller & Lowe, 2016
  10. “In general, organic matter accumulates when programs that dilute organic

    matter are not keeping pace with organic matter production.” Moeller & Lowe, 2016
  11. “0.5-1.5 cubic feet per 1,000 square feet every 7-14 days

    effectively dilutes organic matter throughout the growing season” Moeller & Lowe, 2016
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  13. “To keep organic matter content below 3-4 percent in the

    upper rootzone, these articles recommend core aeration treatments that impact 15-20 percent of the putting surface each year and topdressing programs that incorporate at least 40-50 cubic feet of sand per 1,000 square feet annually.” Moeller & Lowe, 2016 That’s 0.5 to 0.6 inches of sand per year.
  14. Another recommendation “Increasing sand topdressing frequency to every 7 to

    14 days and applying at least 20.3 ft3/1000 ft2 topdressing sand annually, combined with routine soil cultivation to ensure sand incorporation, are practices that can be utilized to manage SOM.”1 That’s 0.25 inches of sand per year. 1Schmid C.J., Gaussoin R.E., and S.A. Gaussoin. 2014. Organic matter concentration of creeping bentgrass putting greens in the continental U.S. and resident management impact. Applied Turfgrass Science.
  15. What I finally noticed

  16. No coring for 13 years, bentgrass in Japan

  17. Minimal coring & topdressing, PGA Catalunya

  18. PGA Catalunya, December

  19. PGA Catalunya, May

  20. PGA Catalunya, January

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  30. What I recommend now

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  37. Recommended approach Check surface zone (0 to 20 mm) organic

    matter once a year Then, compare the OM change to: • annual N rate • annual sand topdressing amount • annual aerification impact
  38. Next level: annual audit