From Dr. Grady Miller’s column in the January 2019 issue of SportsTurf magazine:
Q: Dr. Miller, tell me if we should core aerify this ballfield (pointing at a picture on his phone) this winter? I know it is not the ideal time to aerify but it is rock hard. We could wait until the spring. A few minutes later Dr. Mike Goatley from Virginia Tech joined the conversation and got the same question, “should core aerify this ballfield this winter?”
A: This question was being asked by one of North Carolina’s many talented sports field managers. We had just finished a great breakfast and were getting ready to listen to the morning program at the Southeast Regional Sports Turf Conference in Myrtle Beach, SC. It was November 14 and the buzz around the conference that morning was the ice and snow that was about to move through the western part of NC and Virginia beginning that afternoon.
The person asking the question knew that aerification in the winter months is generally not recommended before he even asked me. He was just looking for another opinion before making the decision. I could tell from the way he was asking the question that he wanted confirmation that it would be ok to go ahead and aerify. I should add that this person is a “semi-retired” sports turf manager. Even though he is retired, I know that he still takes a lot of pride in helping other field managers with their fields. He is frequently sought for his advice as he always produced great field surfaces. In this instance he did not want to give bad advice. So he was using the opportunity this meeting provided to get more information on the dilemma to aerify in winter or to delay until spring.
Whether it is giving advice or making decisions, we often do so based on our own experiences. Several years ago (May 2015), I wrote a SportsTurf “Q and A” on aerification and I suggested that field managers should aerify as often as they can, whenever they can. In that article I mentioned that having open aerification holes when there are freezing temperatures can increase the risk of winter damage, but that the risk is worth it in most situations.
A few years ago a mistake was made at our research facility and one of my bermudagrass greens was aerified in the late fall. That is a common aerification time for bentgrass greens and our field manager at the time did not think it would cause problems with the bermudagrass. We ended up having our worst winterkill ever on that bermudagrass green, partially at least because of that aerification. While a green is much more sensitive to management missteps than athletic fields, that experience was in the back of my mind when I answered that I would not aerify a ballfield this late in the year.
In my mind, his comment about waiting until spring sounded like a better option. He indicated the field was not going to be used much in the next few months, so my suggestion was to wait a few months and then aerify aggressively in the spring and summer. Although I am a big fan of being aggressive with aerification, I tempered my response due to that one negative experience with a green.
Dr. Goatley’s response to the same question was much different than mine. His recommendation was to crank up that aerifier and get to it. His opinion was to get some fracturing now before winter set in and then the freeze-thaw cycles can then further loosen the soil. Dr. Goatley had heard of turfgrass problems after winter aerification, but he indicated that in Blacksburg he has not seen enhanced winterkill on a ball field due to aerification (alone). His response was influenced by his experiences.
Who had the correct response? Well, I believe we both did. Each of us brought out a bit of uncertainty, but we provided our justifications for why we made the recommendations we made. My experiences with a green may never play out on an athletic field. Dr. Goatley’s experiences in an even colder climate may be different in the future, but to date his experiences suggested the potential gain far outweighed the risk. In this instance, Dr. Goatley’s experiences were probably more applicable to the situation.
In the end, neither Dr. Goatley nor myself will be the person operating that aerifier winter or spring. So, what we would do is not as important as what the field manager does. I believe talking through the situation with other people was a great beginning of a good decision. I am not sure of the final decision, but my guess is the field was aerated. And while winter aerification was not my suggestion, I think that how the person came to that conclusion was probably the best decision he could have made.