Walk into any maintenance facility and there's usually a big calendar above the superintendant's desk that is crammed with notes about sprayer applications, outings, and other various records or reminders. In days gone by, a big circle around a date in early September would typically designate the day set aside for coring the greens. With increasing frequency, that bold circled date tends to be found closer to Columbus Day or Halloween instead of Labor Day.

There are plenty of sound agronomic reasons why later summer is better than late fall when it comes to cultivating the greens with hollow tines at courses across the north central tier of states. High soil temperatures during late August/early September encourage the holes to heal over quickly. On the other hand, forget about holes healing over after a few hard frosts occur. Greens that go into the winter with thin, bumpy surfaces will enter the spring with thin, bumpy surfaces; and spring is a time when cold soil temperatures slow down the rate of recovery to a snail's pace.

To be fair, there is no shortage of non-agronomic reasons to schedule an aggressive hollow tine coring as late as possible. The temporary disruption to play was and continues to be the prime reason why coring is pushed to the shoulder season. In today's economy, the loss of revenue associated with closing the course for even one day and then annoying golfers for a week or so comes in a close second. After all, we hope for a dry, mild, sunny day to complete coring operations, and those days are golden when a couple of soggy spring weekends put a big crimp into the season's cash flow.

What to do? Why core at all? Granted, there are a few, and, I do mean a few, golf courses that topdress greens perfectly and manage the turf in a manner that makes aggressive cultivation unnecessary. However, I don't need to take my shoes off to count the number of times during the past 18 seasons that I have made verbal or written TAS recommendations to omit hollow tine coring for greens. In my experience, those who have had the smarts, experience, and luck to manage great greens without any cultivation also have been honest enough to admit that they may need to, and will, initiate a coring program in the future if problems such as layering or reduced water percolation occur. In contrast, there is another group who never core and are in denial regarding serious soil problems, which ultimately becomes the next superintendent's concern.

There are many reasons why greens need to be cultivated regularly. Excess organic matter accumulation in the upper soil profile is high on the list. Topdressing will dilute any additional buildup of organic matter, but the existing thatch needs to be physically removed by some form of aggressive cultivation. Hollow tine cultivation is ideal for addressing a thatch problem because removing the cores from the playing surface is a relatively simple process. Don't chop up the cores and recycle some of the organic matter back into the greens when the purpose of cultivation is to eliminate thatch. Filling the holes with sand provides a smoother surface and accelerates the rate of recovery.

As mentioned above, late fall isn't the ideal time to cultivate greens. However, when excess organic matter is a problem and the only two choices are late coring or never coring, then go ahead and core. Understand and communicate the potential problems of late cultivation to golfers. Make the extra effort to fill the holes with sand in hopes of providing a smoother surface next spring. Filling the holes and leaving a little extra sand on the surface may also help reduce the potential for wind desiccation during an open winter. Halloween coring just may result in some Thanksgiving should wet, hot weather occur next summer.

Speaking of Thanksgiving; you don't want to miss attending the 43 ^rd Annual Wisconsin Golf Turf Symposium being held the week before this holiday on November 18-19, 2008. This year's topic is water, and experts from across the country will discuss critical issues such as wells, best management practices for irrigating golf turf, water quality, water treatments, modern irrigation system technology/innovations, permitting, pond issues, water rights, water conservation and much more. Everyone who manages turf can learn something from this unique educational opportunity…not to mention the excellent meeting facilities at the American Club. Call the American Club ASAP for reservations (800) 344-2838 and mention the Turf Symposium - don't wait if you want the great rate. Contact my office or Shelley Biro at Milorganite (800) 287-9645 for registration information. SBiro@milorganite.com

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