The word aeration means different things to different people. To a golf course superintendent, it is a process that enhances the health of the turf they are charged with nurturing and protecting. To some golfers, aerification is an annoyance or an outright nuisance.
Whether golfers know it, however, aerification is a process that is vitally necessary. This article aims to illustrate why that is the case. Matt Bachmann, the superintendent at Princeville Makai Golf Club in Princeville, Hawaii, explains why aeration is a part of his agronomic program.
“The main reason we aerify anything is thatch removal,” he says. “I think over time you get so much thatch that builds up on the ultradwarf here. We have seed dwarf, which is kind of similar to the new hybrid Bermudas.”
Bachmann explains that over time, thatch buildup creates a virtually impregnable layer between the surface of the grass and the soil. “What ends up happening is, over time, your water sits on the surface,” he adds. “Your nutrients don’t get to where they need to get to, and you can get a spongy surface, probably one that’s more likely to scalp.
“It’s very disruptive and there are other things you can do to mitigate thatch, but as far as removing the entire plug of thatch from the surface of the green to that soil level, where it’s actually a mix of your green and sand, (aerifying) is really the only good option for the long-term health of the greens.”
Jon Lobenstine is the director of agronomy for Montgomery County Golf, which operates nine public-access courses in Montgomery County, Md., outside of Washington, D.C.
“The biggest benefits are continually rejuvenating the playing surface,” he says, “which is constantly being compacted, for example, by mowers, golfers and general golf course activity. Also, by allowing better water infiltration into the soil, we can be more miserly with the water that we do put out.
“One of the goals, obviously, of golf course superintendents is to limit the amount of water that is put on the golf course because it’s the most valuable resource that we have and there are certain places around the country where its use is restricted. By reducing the amount of water, we also reduce disease pressure and help grow roots and generally create a healthier plant.”
While other methodologies have been developed for increasing air circulation through a green, utilizing solid tines for instance, it’s a safe bet the vast majority of superintendents regard the traditional method of punching holes and pulling cores to be the most effective. Ed Shimkus is the director of agronomy at the Wickenburg Ranch, a semi-private facility in Wickenburg, Ariz., an hour northwest of Phoenix.“I believe that pulling a core and removing the organic matter is the main reason why we (aerate),” he says. “Our goal is to reduce thatch and improve the firmness of the putting surface. It also provides the conduit for incorporating sand into the greens profile.”
When and how often a facility aerates is determined by a number of factors including its location, the local climate and the impact on play. The USGA Green Section will work with clubs to help them determine the best times to aerate from an agronomic perspective. But there are practical considerations as well.
Bachmann, whose facility on Kauai’s north shore is open all year, aerates twice a year. This year’s first aeration was May 13-14, with a second scheduled for Sept. 10-11. Ideally, he might aerate in June and again in August but the dates he’s chosen make better economic sense.
“They’re a couple of shoulder seasons,” he says, “when kids are going back to school (in the fall) when it’s heating up on the mainland. A lot of (visitors) over here head home.”
Sometimes, as often happens in the turf industry, Mother Nature intervenes. In April 2018, Bachmann was confronted by a major storm that saw Princeville Makai absorb 28 inches of rain in a day-and-half. He aerated his greens not long after.
“You have to look at the entire golf course and say this is the best thing for our business,” Bachmann says. “It took a little longer to recover, maybe (the greens) weren’t 100 percent ready for it, but by the time we got the golf course back together, the greens were taken care of.”
Bachmann will core aerify his tees, approaches, and green collars. Because his fairways are built on hard clay soil, thatch issues are minimal in those areas. He relies on solid tines instead and verticuts his fairways as deeply as possible without risking turf damage.
Shimkus takes a different approach, aerating once per month in June, July, August and September when play is minimal because of the Arizona heat. The course is closed for three weeks each October for overseeding. The aerification schedule is built into the annual maintenance calendar but is subject to adjustment.
“We might consider moving the specific date if we have an outside event scheduled,” Shimkus says. “The summer months are our ‘off-season’ and mostly geared toward our heavy cultural practices and renovation projects.”
In addition to aerating monthly during the summer, Shimkus and his team will utilize needle tines on the greens during the spring to enhance water infiltration and promote gas exchange.
Jennifer Torres is in charge of the turf at Makefield Highlands Golf Course, a daily-fee facility outside Philadelphia. She aerates twice a year, the first time around April 1.
Torres admits that ideally that aeration would come a bit later but the schedule dictates otherwise. In recent years, the club has hosted a U.S. Open local qualifier in early May. The event was held May 6 this year.
“You might want to wait a little longer for warmer weather,” she says. “You get warmer weather at that time of year, it fills in a lot quicker. The recovery time (for an April aeration) is the same as somebody who did it two weeks later and waited for a warmer period.”
Torres typically does her second aeration just after Labor Day, nine holes at a time. She’ll verticut during the season as needed. Torres points out that aeration is something that is needed to maintain healthy turf. “You have to have the airflow,” she says. “You have to have water get into the roots and (break up) the compaction from everyday play and foot traffic.”
Lobenstine times his aerations to minimize the impact on his courses’ revenue streams. At one time, he typically scheduled core aerations for March, before the season got busy. In recent years, however, he’s adopted different methodology.
“We’ve actually gone away from our typical spring core aeration,” he says. “Now, most of our courses are typically doing one core aeration (per season), typically the three weeks of August with the goal of being healed up by the Labor Day weekend.”
Lobenstine notes that his courses typically experience a lull in activity in late summer, making it an optimum time to aerate. There are agronomic considerations as well.
“The other benefit of aerating in August is we limit the amount of Poa that germinates on the greens,” he says, “or the fairways, if that’s what we’re doing, because Poa really tends to germinate and start becoming an issue in September when the weather cools off a little bit.”
Lobenstine follows up the late summer aeration in November, utilizing a sand injector. “One of the reasons we do this is because it helps keep up with the dilution of the thatch,” he says, “which is important, but also because these lines, while they are visual in their appearance and they do hang around for most of the winter, the surface of the greens tends to be much smoother than if we had done a core aeration in November.”
Shimkus points out that today’s aeration technology shortens recovery time and minimizes impact on play, and not incidentally, the impact on a facility’s bottom line.
“I haven’t used a tine on the greens larger than 3/8ths of an inch for over 10 years,” he says. “The influence of quad tines at tighter spacing removes just as much organic as larger tines. However, ball roll and turf recovery are much improved in a shorter time period.”