Aerification: a necessary evil of turfgrass management

When it comes to aerification, superintendents are forced to maintain a delicate balance between aerifying enough to keep turf healthy and free of disease and decay, and taking into account the disruption of play aerification causes, which is no small problem as far as players are concerned.

While superintendents aerify greens, tees and fairways, it’s greens aerification that causes the most disruption and for which they receive the most grief.

To say greens aerification is among the most dreaded operations at a golf course might be an understatement. Finding the happy medium between healthy turf and member convenience can be challenging, but aeration is a necessary evil because of its many benefits.

According to Ron Kuhns, superintendent at Sun Willows Golf Course, a city-owned facility in Pasco, Wash., the major benefit of aerification is to relieve soil compaction caused by players and equipment. Compaction can be substantial throughout the year.

"Even though I’m not driving bulldozers on these greens, people walking on them causes a lot of compaction," Kuhns says. "That’s a lot of pressure per square inch under somebody’s feet."

To maintain the low-cut (5/32 of an inch or lower) greens that players demand and to keep tees and fairways at their ideal playing heights, superintendents need to develop and maintain a deep, healthy root system. This means ensuring optimum levels of oxygen are getting to the root system to support the plant above ground. When greens become compacted, these air pockets are eliminated, leaving little air in the soil and making it harder for water to penetrate, causing roots to suffocate and wither away. If that happens, then a superintendent will have a larger problem than inconveniencing players for a few days to aerify.

Another benefit of aerification is it opens air pockets, improving the absorption of fertilizer and water to the root zone, says Peter McDonough, superintendent at The Keswick (Va.) Club.

"In the soil profile or sand profile, you either have air or water consuming space," McDonough says. "Obviously, air is much more preferable. If you get air circulation into the soil profile, you’re going to have plants that breathe, and you get that water to penetrate instead of being on the surface."

The USGA Green Section recommends courses aerify greens twice a year, but some argue the more it’s done, the healthier the turf will be. Unfortunately, that won’t always wash with a membership or green committee.

Jeremy Stachowitz, superintendent at Wahconah Country Club in Dalton, Mass., core aerifies greens in early May and early September, which he combines with a vertidrain aeration in late October or early November. However, the course could use more aeration, he says. If Stachowitz had his way, he would probably do two aggressive core aerifications with half-inch tines and then use hollow-claw tines monthly, which would only take about a week to heal, he says.

"Even just doing the two per year and the vertidrain is not nearly enough for what this golf course needs, but it’s about as much as my membership will tolerate," he says.

Like Stachowitz, most superintendents try to aerify the greens in the spring and fall, during off-peak times. Then they focus on tees and fairways whenever they can throughout the year, although not everyone can get away with less.

"Twice a year used to be standard years ago, but now there are quite a few golf courses that do it once," Kuhns says. "We tried doing it just once in the fall and not doing it in the spring. We ended up having some disease issues in the summer because we didn’t open it up in the spring."

The healing process

The most common aerification practice is removing soil cores or plugs and then topdressing to fill the holes that are left, usually with sand and other amendments such as fertilizers that allow the soil to maintain its air space and improve water penetration.

The time it takes to punch the greens with an aerifier is only half the problem in players’ eyes. The other problem is the holes that are left. The time it takes them to heal varies from course to course, but it averages two to two-and-a-half weeks, Stachowitz says.

"I get more complaints from the longevity they may take to heal and from the timing of the aerification," he says. "The September one comes at a peak time playingwise, but it’s also the best time of the year to do the aerification. The members would rather see me do it in October or so, but by then, it’s too late to get them to heal."

Tim O’Neill, superintendent at Country Club of Darien (Conn.), might alter his schedule this year to allow the greens to heal more quickly than last year, when he did his traditional fall greens aerification in conjunction with a drill-and-fill project.

"Those holes were evident in my greens for a long time," he says. "If we aerate the greens during the growing season, like in September, the holes will only be there for a couple of weeks. If we do it at what amounts to the end of the season, it takes six months to grow any grass at that time of year."

For this year’s spring aeration, the holes were healed within two weeks, O’Neill says.

Fairways and tees

While aerifying greens causes the most disruption at a course, fairways are a close second, Kuhns says. Because Sun Willows is owned by the city, Kuhns doesn’t have the luxury of having all the equipment the course needs in-house. So his aerification schedule is based on what he can borrow from neighboring courses. In spring and fall, he borrows an aerifier and a couple of laborers to finish the greens in one day. For fairways, which are on less of a set schedule based on what’s available for equipment, he uses a Renovair because of staffing limitations.

"I try to do fairways twice a year, but I try to do it when I can get the equipment," he says. "Doing fairways takes almost a week, and the cleanup can be a disaster."

Tees present the least amount of trouble with disruption in play, Kuhns says.

"Tees are easier for me," he says. "I do those three times a year in spring and fall and when it starts to get hot. Those are really easy to clean up because they aren’t really big."

At Keswick, McDonough aerates fairways the week after Memorial Day and the last week in July. The timing is based on the optimal growing season for Bermudagrass, which is overseeded with rye. Tees are on the same schedule.

"We aerify again during the last week in July because that’s when my soil temperature and the Bermudagrass is at its peak for growth," he says. "That’s when you’re really going to be able to give the roots and shoots plenty of time to develop."

In addition to the two aerifications, McDonough puts blades on his aerifier to slice the fairways four or five times a year, which is one of the most underrated practices around, he says.

O’Neill spreads out his tees aerification over a longer period of time because his club has multiple tees and he can aerate one without interrupting play.

"I don’t feel that I have to get it done over two days," he says. "The holes that only have one tee I’ll take care of on a Monday so I don’t have to disrupt play."

Communication is key

Superintendents have differing ways to deal with the disruptions in play. It depends on the type of course they maintain. Kuhns closes his course for a day and brings in extra labor and equipment from neighboring courses.

"With all the extra help and machines, we can get all 18 greens done in one day," he says.

Sun Willows is owned by the city, but IRI Golf Group leases it. Because IRI also manages nearby Columbia Point Golf Club in Richland, Kuhns says his course can make special arrangements to accommodate its members who are displaced during aerification.

"When we aerify, we do a deal between the two. We let our members go over there, and when they punch, we let their members come here, at a greatly reduced rate," he says.

O’Neill has the added benefit of his club’s Monday closure throughout the season. This allows him to run his aerifier over nine greens each on a Monday and Tuesday, but only disrupt play on the back nine on one Tuesday in the spring and one in September.

"Between a club that has the option to close on a Monday and one that doesn’t, it is easier," he says. "I don’t have to worry about any play on that day."

He does the same thing with fairways because he can’t work around people when he’s doing fairways. Even though O’Neill has an understanding membership, he says communication is key.

"Keeping the green committee and the grounds chairman and the members informed as to what’s going on is important," he says. "It helps when they understand the process."

Because Keswick is a resort as well as a private club, McDonough says the pressure is on to maintain the course at optimum levels without any major disruption in play.

"You’ve got to give players nine holes, especially when you’ve got a hotel to support," he says. "When they do central reservation booking, they make sure that they know what’s going on with aerification. We can make our membership aware of it quickly and constantly, but anyone who shows up as what we call a ‘member for a day’ is notified ahead of time, even if we have to call them at their house to let them know."

To ensure play continues during aerification, McDonough does nine holes at a time, spread out over two days. Unlike Kuhns, he aerates three times a year – the beginning of April and the end of September with half-inch tines and once in July with quarter-inch tines. The July aerification has helped alleviate problems with excess water at the course.

"With all the rain we’ve had since the drought problems a couple years ago, we’ve been waterlogged," McDonough says. "We find that doing it with those quarter tines just gets some air movement into the soil profile. That really helps immensely with a whole host of issues."

Another benefit of aerating with the quarter-inch tines on his Toro aerifier is that the holes are smaller and heal more quickly.

"With the quarter tine, you get small holes that, at this time of year, heal over rather quickly after a couple of hand mowings," he says. "Within a week, they’re almost unnoticeable."

Plugs, plugs everywhere

Aerifying greens and fairways results in a lot of plugs on the turfgrass. So what do superintendents do with those plugs? In Stachowitz’s case, he attaches a core harvester to his Toro Workman to collect them. From there, he uses them for just about anything – filling in fairway holes, creating a green nursery or anything else he can think of.

"Those things are like gold," he says. "You don’t just throw them away."

Kuhns also reuses the cores, particularly those from tees.

"We run a core harvester over the area that picks up the plugs and shoots them into the bed of the Cushman," he says. "Then I just put them in a pile behind my shop, and when we’re all done aerifying, I put them in bare areas. Each one is a mini yard, about 5/8- to 1/2-inch across. We’ll spread them out in a bare area, roll them and fertilize them, and in about two weeks, it grows together, and you’ve got grass."

McDonough has a different take on cores. Being a private/resort club, his priority is keeping the unsightly piles off the premises. Rather than collect cores from fairways, McDonough uses a Lacy core pulverizer, which turns them into dust.

"We’ll use the core pulverizer, then we drag in the afternoon, which almost acts like a topdressing. If you give it a nice watering and cut the fairways the next day, it’s not noticeable," he says. Any clumps that are left behind during wet conditions are then scooped up before the holes are reopened for play.

"There’s never a problem with aerifying as long as you present the product open again as clean as possible," McDonough says.

Turfgrass management

Despite all the headaches that come with aerification, superintendents have learned that, for the most part, not doing it isn’t an option. It’s simply something that must be done, whether members like it or not.

"Everybody’s situation is different, and I don’t know if members always understand that," Stachowitz says. "In their minds, there’s never a good time to do it, and in superintendents’ minds, we never do enough."

Kuhns agrees the benefits far outweigh the drawbacks.

"It’s a pain in the rear end, and I don’t like doing it, but in the long run, my greens are healthier," he says. "It’s just good turfgrass management." GCN

Derek Rice is a freelance writer and editor from Portland, Maine. He can be reached at 207/541-1928.