Managing for the Greatest Common Denominator

Over the last few years much of our turf management philosophy has focused on managing for the greatest common denominator. It’s a topic I have spent a lot of time discussing with a friend and fellow Golf Course Superintendent, Chris Tritabaugh of Northland Country Club in Duluth, Minnesota. During these discussions we have both concluded that many of us manage for the lowest common denominator. This is to say as superintendents our ultimate job is to maintain the golf course in such a manner that we never lose turf. No matter what the species, no matter what the cultivar, our job is to see that no turf is lost.

So what does that really mean? Basically there are two types of turf that Superintendents in the northern region of the country manage, creeping bentgrass and poa annua. We all know that creeping bentgrass is the stronger species of turf and poa annua is the weaker species. However, on average most Superintendents will manage for the weaker grass type, poa annua. Why? If poa annua is the weaker grass why do we manage it, support it and spend thousands of dollars keeping it alive when a stronger species is also present?

Many in the golf industry know that for the past 3 years we have been working with the consulting firm of Greenway Golf and have been implementing many ideas and concepts from Marc Logan, all in an attempt to promote and manage for, on our greens, tees and fairways, creeping bentgrass. Many of the concepts have been around for decades, Marc has just been able to incorporate some old concepts with new technology. The philosophy is based on cultural and nutritional concepts that encourage the promotion of the greatest common denominator, creeping bentgrass. Good, solid, practical greenkeeping.

It’s quite interesting if you really think about it. Superintendents go out of their way every day to make sure they don’t lose the weakest strand of turf on their fine turf areas. Extra water required to keep the plants alive during the heat of the summer, or additional fertility necessary to feed and maintain the weaker species and frequent fungicide applications insuring disease does not kill the less healthy plant.

Over 15 years ago I worked for a Superintendent by the name of Scott Austin. Scott had been the Super at Midland Hills Country Club in St. Paul, MN for 20 years. His greens were firm, fast and made up of a majority of creeping bentgrass. Greens were single cut with Toro 1000’s at .125”, never rolled and stimped around 10’ to 10.5’ daily. One thing we never did in the 4 years I worked for him was hand water greens. His theory…"if we start to syringe greens in the afternoon, that plant is then going to become conditioned to receiving this water and we don’t want that to happen.” Deep infrequent watering cycles was how he managed. Sure there was poa in his greens, but even the poa was conditioned and evolved to accept those conditions.

After my time at Midland Hills, I made the move to Minikahda, this was 15 years ago. The poa plants on our greens had been conditioned to the point if the sun was high and shining, you better have a hose in your hand or you were going to lose some turf. My goal in the first 5 years I was the Supt. here at Minikahda was to try and find a way to condition the poa to not be so weak. Find a way to reduce the dependence on daily hand watering and nightly water cycles. Find a way to reduce the dependence on high fertility inputs, namely nitrogen.

Now fast forward to the past 3 years. Out goal since hiring Greenway Golf is to slowly transition our greens to a predominately creeping bentgrass stand. How are we doing that? We are doing this by favoring the stronger grass species through cultural and nutritional practices; managing for the highest common denominator. Acid based fertilizers, deep infrequent watering cycles, and reducing surface disturbance to the finer turf playing surfaces are all a part of our philosophy.

This past summer through no one’s fault but my own, I got a little aggressive in trying to force the growth of the creeping bentgrass population. In the process we lost some poa annua. Did we lose it all, no, but we did lose bio-types of poa annua, which were typically the ones which we had to “baby” to make it through the summer. We lost the bio-types we always worked our butts off to keep alive. We lost the lowest common denominators.

As we progress through our journey to manage for the stronger species, I know there are many out there who are nay sayers, they shake their heads, they think to themselves, what we are doing can’t be done. You’re always going to have poa to deal with. I say fine, your right, poa annua will always be around to deal with. In fact we have some very strong and resilient bio-types of poa annua in our finer turf areas. Great, if they are the strongest type then they deserve to be here right along with our stronger bent varieties. In the meantime as we transition, there may be times when we may lose some poa annua. If by chance those bio-types can’t handle what we are doing, then they probably don’t belong to be in the mix with the greatest common denominators.

The evolution of turf species on a green can be quite interesting to watch. If the turf is over managed, meaning over-watered and over-fertilized, it’s my feeling that those plants then become dependent on those inputs to survive. Reduce or remove those inputs and those plants will struggle to survive under the same maintenance regime. If those same inputs are slowly weaned from the system those plants adjust and evolve to accept those changes and during the process, the greatest common denominator (creeping bentgrass) begins to become the dominant species as it requires less inputs than poa annua.

Our ultimate goal of a dominant stand of creeping bentgrass on our greens and fairways will take time. There is no magic formula, just persistence and patience. But in the long run through our change in philosophy we will continue to provide excellent playing surfaces as well as provide a sustainable managed golf course.