We aerified the greens with 1/2" hollow tines, 2 directions, 1.5" centers and a depth of 4". This process removed an estimated 25% of material from the putting surfaces. This percentage is based on the formula from the International Sports Turf Research Center (ISTRC). Aerification will improve turfgrass quality and longevity. Although many golfers despise this cultural process, this is a necessity for putting surface integrity. The holes should heal in 10 - 14 days.