The How's and Why's of Aeration

As part of the routine maintenance we finished aerating all the putting greens on the course last week. Everybody accepts the necessary evil of aeration but nobody likes it including the crew that has to do it. The shallow aerating performed this time out was to get oxygen down to the roots. Traffic from maintenance and play compacts the upper few inches of the root zone resulting in a decrease of available oxygen for the roots.

A quick and brief review of plant biology: grass is an autotroph a term which means it can create its own food. The process is called photosynthesis and the end products are glucose and the byproduct oxygen. Grass will use the "food" it created in photosynthesis to grow. The energy required for growth comes from a process called respiration which requires atmospheric oxygen (i.e. the plant has to absorb it). Seems strange that plants can create oxygen on one hand but on the other hand still need to absorb oxygen.

Another reason for aeration is removal of thatch from the upper surface. Thatch will affect nutrient availability, water peculation, playing conditions, incubate diseases, and contribute to poor/shallow rooting. A general rule of thumb is to aerate two times a year with 5/8 " hollow tines just to keep up with the thatch created by the turf in one growing season. The recommended volume of displaced material is from 20-25% per year. That translates in to 2 aeration's using 1/2" tines on a 1.25" spacing followed by two 1/4" aeration's on a 1.25" spacing throughout the growing season. Not goin' happen.

We keeping trying different things to find an agreeable process that provides a benefit to the turf with a limited disruption to playing conditions. This time out we used 1/4" tines on a 1.5x1.5 spacing that resulted in about 3% removal of organic matter. We picked the cores with a sweeper bought this spring and followed up with a medium top dressing. A traditional aeration requires the course close on an afternoon with any number of temporaries in play the next day while we top dress. Also, we require two aerators (we borrow one) two top dressers, 4 people to collect cores, 1 person to broom in the sand; 9 people. This time we used one person to aerate, one person to collect cores, one person to blow debris, one person to top dress: 4 people. We were able to do 7 greens/day with no closure and no temporaries.

The hope is we are able to perform 2-3 of these aerations over the golfing season (May, June, August) followed by an aeration with larger holes once we close for the season which would remove about 9-15% of the surface area (depending of the type of fall aeration: hollow core vs. verti-drain). Time will tell.