Superintendents aerate putting greens and apply sand topdressing to relieve compaction, increase water infiltration and oxygen exchange, and reduce organic matter concentration. One pass across the greens is common for a typical aeration event, but that may mean missing an opportunity to increase sand incorporation and ultimately expedite the process of improving agronomic health. Superintendents usually only have one or two opportunities per year to conduct these intensive cultural practices so it makes sense to maximize the time.
Dave Nakama at Waialae Country Club in Honolulu, Hawaii, takes full advantage of the two annual course closures for maintenance to conduct three aeration passes on each of the ‘Tifdwarf’ putting greens. All three passes are made with 0.5-inch-diameter solid tines on a spacing of 1.5 by 1.5 inches. The two variables that change are the depth and direction of each pass. The first pass is made at a 2.5-inch depth, the second pass is shallower at 1.0 inch deep, and the final pass is made at just 0.5 inch deep to prevent the aeration machine from “heaving” the surface. The direction changes by approximately 30 degrees on each pass. Sand topdressing is applied prior to the first aeration pass.
The healing time is no different than if only one pass was made. Hole diameter determines the healing time, so making more holes doesn’t mean more time to heal. While the aerator does make some bigger holes when the tines hit the sides of holes made on a previous pass, the impact is negligible.
Nakama completed the “thrice is nice” strategy in September and again just recently in March. He finds he can incorporate sand into the canopy and rootzone much more effectively with multiple passes. After just one week the greens are already healing nicely. This process has gone so well that Nakama is considering making a fourth aeration pass during the closure in September.
This is a labor-intensive process, but it is easier using solid tines instead of hollow tines. In terms of scheduling, the course closes nine holes for one week and then completes the process the following week on the remaining nine holes. The team performs aggressive aeration and dethatching on all the closely mown turf during these closures as well.
Consider making multiple passes across greens to get the most from your aeration opportunities. Experiment first with tine size and spacing for each pass, and be sure that the greens are healthy and strong enough to accommodate multiple passes. Note that this strategy works well on all turf varieties, even annual bluegrass. If you would like to learn more about multiple-pass aeration and want to supersize your surface organic matter management program, please reach out to your local USGA agronomist for guidance.
West Region Agronomists:
Brian Whitlark, regional director, West Region – bwhitlark@usga.org
Ross Niewola, agronomist - rniewola@usga.org
