Here’s the best analogy that I learned in school: over time the traffic from both the golfer’s feet and mowing equipment compacts the soil under the putting green. When the soil becomes compacted, the air pockets which the roots depend on are crushed and the roots are left without air. Without oxygen, the grass plants become even weaker and will eventually die.
The mechanical process is done by removing half-inch cores (which are those plugs that are sometimes left on the fringe) from the compacted soil, allowing for an infusion of air and water that brings a resurgence of growth. From there the mini holes are filled with sand, which in golf world we call topdressing, it is then that over seeding occurs. This helps the soil retain air spaces making it easier for the roots to grown downward.
For those of you golfers who have seen this process unfold, the number one question I get asked is: “Why is so much sand applied?” Playability is our number one concern after aerifying, by filling each of the aeration holes with sand it will promote quicker recovery and improve ball roll. Unfortunately the playing surface is not as smooth immediately after this process but the effects on playability as a result of aeration can be minimized if aeration holes are completely filled with sand. The short answer to the question is that by applying enough topdressing sand to fill aeration holes it will result in a smoother post-aeration surface that recovers quicker than a surface with open aeration holes.
Timing is everything when it comes to aeration. Depending on your golf course location and your grass type means that your course could be aerated in mid-August to early September. Most courses in our area the desired turf is Poa annua, where aeration can be performed later in the fall. There is less chance for stress on Poa annua in the late summer early fall. Your golf courses tournament and league play will also play a part in when the Superintendent can do the aeration.