New greens require plenty of sand topdressing during and after establishment to dilute organic matter accumulation that naturally occurs in the upper soil profile. Ultra-dense cultivars of creeping bentgrass are particularly susceptible to thatch problems when appropriate aeration and topdressing programs are put on the back burner.
The example used in this article, and as seen in the photo, involves a golf facility with greens re-established with a newer, ultra-dense bentgrass cultivar. Aeration and sand topdressing did not keep up with thatch accumulation during establishment or in the years following. Several years ago, a new superintendent was hired and he inherited putting greens with five seasons of excessive thatch accumulation. He made a good decision to aggressively remove organic matter from the upper regionalUpdateContentzone using a Graden Sand Injector. Two years of deep cultivation during spring and fall had the greens moving in the right direction. However, the accumulation of sand from light, frequent topdressing applications has now moved the thatch layer deeper in the soil profile to the point that a portion of it is now out of reach for the Graden blades. As a result, there is no longer a sand channel connection between the surface and the construction regionalUpdateContentzone mix used to build the green. So, it is time to shift from Plan A to Plan B.
Hollow tine core aeration to a depth just below the dense layer of organic matter accumulation is an effective Plan B. Use 1/2- to 5/8-inch hollow tines on a close spacing, remove the cores and fill the holes with straight sand during spring and fall to provide an effect similar to the Graden unit. No doubt, less aggressive cultivation would be necessary now if a priority was placed on appropriate organic matter management during and after establishment; but, as the popular FRAM® oil filter television commercial stated years ago: “You can pay me now, or pay me later.”
Information on the USGA’s Turf Advisory Service
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