Say Aloha To Organic Material April 15, 2013 By Larry Gilhuly

Deep vertical mowing causes a temporary discoloration of bermudagrass and seashore paspalum fairways. However, the improvement in playing quality and turfgrass health makes the process well worth the effort.

Excess organic material is the bane to growing and playing conditions for every portion of the golf course “down-the-middle”. While this is less of an issue in locations where less fertilizer is used, it remains a major problem in the U.S. with Hawaii being no exception. Golf courses in Hawaii are now comprised of primarily two grasses (bermudagrass and seashore paspalum) with neither showing any signs of slowing down growth when ample fertilizer is applied. With the vast majority of golf courses being either resort or high-end private, the desire for green color often leads to the production of excess organic material. As we all know, excess organic matter holds too much water, produces localized dry areas and creates playing conditions that are simply too soft. However, visits to two golf courses on a recent trip shows that positive signs are occurring when dealing with organic matter accumulations on fairways, approaches and collars.

Waialae Country Club is well known for hosting the first PGA full-field tour event every year with the Sony Open. Over the past few years, Superintendent Dave Nakama and his staff have significantly improved the playing quality of the fairways and approaches. As one of the few true “bump-and-run” golf courses, the focus has been on organic removal with an annual deep vertical mowing program. While the fairways have certainly improved it is in the approaches where this program has payed huge dividends. In addition to regular aeration, core removal and sand topdressing twice annually on the approaches leading into the greens, a significant amount of organic material is removed annually with deep vertical mowing. As can be noted in the accompanying photo, the fairways and approaches may not look good immediately after the process but recovery is fast. The end result is much improved ball release and roll which is greatly appreciated by the regular membership as well as the PGA tour.

Mid-Pacific Country Club is found on the opposite side of Oahu where the same type of aggressive program on the approaches has resulted in the same improvements realized at Waialae. However, Superintendent Jason Amoy was also faced with relatively high “collar dams” that were impacting ball reaction. Collar dams generally form next to the green and are typically caused by the circular dragging of sand following topdressing. This problem is often addressed through complete removal and replacement of the sod as detailed in the article, Strip Em Bare. However, at Mid-Pacific, Jason needed a way to get fast results without green closure so he decided to employ the same deep vertical mowing idea used in the fairways and approaches. First, the collar is deep vertical mowed with a Graden walking unit. Since the bermudagrass is deep regionalUpdateContented, Jason then takes a high pressure hose and cleans the open sand slits with the sand going off the raised area. He then uses the putting green roller or triplex mower to flatten the area with the bermudagrass filling in the open slits in a short period of time. Jason reports that performing this operation once annually has significantly reduced the “collar dam” problem.

Aloha can serve as “hello” or “goodbye” in Hawaii. In these two cases the superintendents are saying aloha to a real problem while the players are saying aloha to golf courses that are more fun to play.

Source: Larry Gilhuly (

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