2009 is in the rear view mirror. Good! It was a year that everyone wants to forget, but no one will. Planning for the 2010 growing season is underway, and we will focus this article on developing an aeration and topdressing program for the upcoming year. Isn’t it ironic that whether the economy is booming or in recession, scheduling these tasks is difficult? We heard for years in a healthy economy that aeration needed to be deferred/skipped/compromised because of the associated loss of revenue. Yet, when rounds plunged in this recession, we hear that courses are contemplating deferring/skipping/compromising aeration because of revenue concerns. Some things never change.

The Importance of Aeration

One of the key functions of core aeration is the physical removal of organic matter and the replacement of this material with sand. For a complete discussion of the role of aeration and its importance as a cultural tool in a putting green management program, refer to the article, "Aeration and Topdressing for the 21^st Century" that appeared in the Green Section Record: /content/dam/usga/pdf/imported/030301.pdf.

Bentgrass Putting Greens

The question of how much to aerate bentgrass putting greens and when to aerate are questions we field regularly. Based upon the research conducted by Dr. Bob Carrow at the University of Georgia, the goal should be to apply a total of 40 – 50 cubic feet of sand per 1,000 sq. ft. through both core aeration and topdressing. Since the goal is dilution of organic matter, it is useful to think of aeration and surface topdressing together since they both help with this goal. This recommendation can be difficult to conceptualize. Practically speaking, it can be reached with three core aerations using 5/8" diameter tines on 2 inch by 2 inch centers. Two of these aerations can be combined on one date in the spring and the third can be done in late summer or early fall. Surface topdressings should be done regularly throughout the season.

Scheduling aeration and topdressing applications for the year is a step in the right direction as we move to the next growing season.

Ultradwarf Bermudagrass Putting Greens

On non-overseeded ultradwarf bermudagrass putting greens, less aeration is required and it can be done on one date in the middle of the summer. An approach we like is to use 5/8 inch tines on the tightest spacing possible, assuming no mechanical damage to the putting green other than the removal of the core. This method allows the golf course superintendent to provide 49 weeks or so of golfing conditions not disrupted by aeration. Topdressing should be applied regularly throughout the season assuming the ultradwarf is growing.

What if the appropriate program is overruled by the economy?

Sometimes golf courses are not able to do what is agronomically appropriate. What will happen if the greens are not aerated as extensively as desired? First, unwanted organic matter will continue to accumulate. Most likely your putting greens began as a sand rootzone with particles of organic matter floating in them. As aeration is deferred and organic matter levels increase through the deposition of old plant parts and roots, this sand rootzone is transformed into a sea of organic matter with sand particles floating in it. Unfortunately, a high organic matter rootzone has physical properties with fewer large air-filled macro-pores that can lead to many secondary problems such as disease, shallow roots, a propensity to scalp, algae, softness, etc.

If you are not able to aerate at the desired level, the rescue technique is to use solid tines or the Hydro-ject every three weeks throughout the growing season. This will increase soil oxygen levels and will help water drain through the profile more readily. Please be advised this suggestion is not a replacement for core aeration or a recommendation to skip aeration.

Conclusion

Aeration and topdressing are no fun for the crew and can be disruptive to golf. However, the life of the putting greens is longer than a single season and the effort needs to be made. There is an old saying, "Pay me now or pay me later" and this certainly rings true with core aeration. We wish you the best with getting these important practices on the books for 2010 and stand ready at your request to be of assistance at your facility.

Source: Patrick O'Brien 770-229-8125 or patobrien@usga.org and Chris Hartwiger 205-444-5079 or chartwiger@usga.org