Aerate Great

Even for courses local to each other, the right timing for aeration and quick, reliable healing is different.Aeration: It’s that dirty, vile word that no golfer ever wants to hear. And as much as golf course superintendents try to ease these golfers’ pain when it comes to having to perform this necessary procedure, they never fail to feel their wrath.

Needless to say, the more quickly superintendents can get their greens, fairways and tees to heal after aeration, the better. The goal is to minimize turf damage to ensure a quick recovery, and there are several factors that contribute to this happening.

Probably the biggest factor, according to USGA agronomists, is soil and air temperature. If aeration isn’t done when these temperatures are ideal, there isn’t much superintendents can do to speed up the healing.

“The number one factor in healing is soil and air temperatures,” says Darin Brevard, USGA Green Section agronomist. “If you don’t have them for the particular grass you’re growing, you’re not going to get healing.”
Fellow USGA Green Section agronomist Pat O’Brien agrees.

“Hopefully aeration is done at a time when the grass is growing and not when it’s in semi-dormancy. Otherwise the holes will obviously last longer.”

Brevard says that “ideal time” varies depending on region and turf type. For example, the perfect time to aerate a Bermudagrass green is not the perfect time for a bentgrass or Poa annua green. In his region, the Mid-Atlantic, the time to aerate is anywhere from March to May and then August to October.

“Everyone has their own preference,” Brevard says. “Some people try to get it done early and get it out of the way and hope they get enough warm weather in March that it heals. Others try to wait till the weather is more reliable so that disruption time is a lot shorter.”

Golf course superintendents Kevin Jones and Terry Boehm understand the importance of aerating when temperatures are ideal. But despite the fact that their golf courses are both located in Northeast Ohio, each chooses a different time to perform this critical process.

For Jones, who is the superintendent of the private Red Tail Golf Club in Avon, Ohio, performing his fall aeration the day after Labor Day and spring aeration during the first week of May seems to work out the best. In spring, Jones prefers the Monday after men’s opening day, or the first week in May.

“By that time, your soil temperatures have come up and you’re getting the good daytime temperatures and the sun angles have changed and the days are getting longer,” he says.

In fall, Jones and most superintendents in his area aerate right after Labor Day.

“A lot of people do it the day after Labor Day, and I like it then because you heal so much faster versus pushing it off till October when it’s cool and you don’t have many growing days left,” says Jones. “If you do it late, you’re still looking at holes come spring versus if you do it after Labor Day and you’re done in two weeks and have the rest of fall to have great greens to play on.”

Jones admits, however, that aerating right after Labor Day is not without its risks in that the golf course could still see 90-degree days, in which case “you’re really doing a lot of babysitting out there with hoses.

That may be one of the reasons Boehm, at Avon Oaks Country Club in the same city as Red Tail, prefers a different schedule.

“I’m a little later than most guys,” Boehm says. “For fall, I don’t aerate till the first Monday of October. On Sunday night, we shut down the first tee and follow the last group around. In spring, we do it right at the tail end of Memorial Day weekend, coming in Monday night and shutting down the first tee at 5 and then following those golfers around and getting as much done as we can that day, then coming back in Tuesday and finishing everything up. Because I do it so late in spring where it’s darn near summer, the recovery is pretty quick because the soil temperature is right where I need it to be.

“Those two dates work well for me, but they might not work quite as well if I was down just a little further south. Being so close to [Lake Erie] keeps our soil temperatures up. We’re cooler in spring but warmer in fall. But 15 miles south of here, we’ll see frost two to three and sometimes four weeks before we get it here.”

The USGA’s O’Brien is located in the Carolinas and Georgia, when greens frequently are aerated in March and then “all of a sudden we can get cold temperatures at night on bentgrass greens.”

“But a lot of superintendents are locked into specific times based on the golf calendar,” he says. “We do have an outdoor sport here.”

A crucial factor in the aeration and healing process is getting sand into the upper half of the soil profile to dilute organic matter.

“That’s the key – dilution with sand,” says O’Brien. “You’re trying to keep that organic matter in the upper two to three inches of the profile, below that four to five percent level. It’s the amount of sand that dilutes it, not the number of holes you punch. And it’s applying sand not only in the holes during the aeration process, but also applying a certain percentage through surface topdressing throughout the year.”

Sand also serves to minimize disruption to golfers, says Brevard.

“If you can fill the holes to the surface, you’re going to have a smoother surface right after aeration and the holes will generally heal more quickly as well,” he says. “Plus, if you fill the holes with sand, you’ll maximize the benefit for the disruption you’re causing.”

On Red Tail’s California greens, which are 100-percent sand-based, Jones does all the cleanup by hand after coring.

“We use come-alongs to windrow all the piles, and then scoop them up by hand,” he says. “We topdress and also brush by hand, too. After the aerifier goes through, it can basically dig the holes and then it’s possible to fill the columns back up. Doing it by hand works as long as you don’t fill those channels up.”

Jones says he’s more careful with the greens since there is less tolerance for damage. Fairways are all aerated mechanically with no handwork, but tees are treated the same as greens. The only difference is that he uses a cocoa mat on the tees versus hand brooming in the topdressing.

“We do hand-pick and windrow all the cores on the tees, though, and scoop them up,” he says.

Boehm uses a core harvester on the greens at Avon Oaks, and then he runs a topdressing brush over them followed by a blower for whatever is left behind.

“The brush loosens up anything packed down on the surface,” Boehm says. “Then the blower cleans everything up pretty well. When the greens are on the drier side, they get perfectly clean. But if they’re a little damp, it’s a slower process.”

The USGA’s Brevard cites sand injection as a great way to get sand into the top two to four inches of the soil profile.

“Plus, it’s certainly not as disruptive as traditional core aeration,” he says, though he cautions that it shouldn’t be viewed as a replacement for core aeration.

“It’s something to be done in addition to core aeration, or perhaps you can use a smaller aeration tine in conjunction with dry-ject aeration,” he says. “The combination of the two may provide less disruption for golf but still quite a bit of agronomic benefit.”

Boehm doesn’t utilize sand injection but has seen the process at work at neighboring golf courses and likes the results. “There’s very minimal disruption to the point where you can go out and play on those greens the next day,” he says. “Yes, you can see some sand, but the greens still putt very well.”

O’Brien believes equipment has advanced well enough where it should also contribute to lessening damage.

“This better equipment minimizes damage but also allows us to do a better job of addressing organic matter issues in the upper part of the profile because we can really do a lot of amazing things with tine spacing, tine size, etc.,” he says. “These things really take nice pieces of turf out of those holes. If there is less tearing and disruption by the machine during the process, the turf is obviously going to heal better. Keep in mind that if you do the surgery, you have to have a sharp scalpel.”

Whereas superintendents used to use a 5⁄8-inch tine, Brevard says most are opting for a ½-inch size now. The flexibility to use different tine sizes is all that’s changed. “In terms of actual damage from equipment, you never really saw any problems with the old aerators, you just didn’t have the flexibility to use different size tines that you do now,” he says.

Boehm uses three different aerators at Avon Oaks, two older 24-inch walkers and a 30-inch that he says he uses as little as possible. “It doesn’t punch nearly as good a hole, so the recovery is slower,” he says. “But to get all the aeration done in the right amount of time, I need to run all three machines.”

Can chemicals actually promote faster healing?

Perhaps Darin Brevard, USGA Green Section agronomist, put it best when he said this about chemical products that claim to promote faster healing after aeration: “I’ve been with the USGA for 15 years, and it seems like every three years someone comes out with the next great elixir to speed healing from aeration. But 15 years later, we’re still asking the same question.”

In other words, he subscribes to good old nitrogen fertility as the most important thing to do to get the grass growing. He has heard of a soybean extract that is touted as having the ability to encourage grass to heal more quickly, but he couldn’t vouch for its effectiveness.

One week before aerating in spring and fall, superintendent Terry Boehm fertilizes with nitrogen so it “kicks in” by the time aeration begins. And despite aerating, he doesn’t back off his program of using a growth regulator in spring.

“I don’t know if it would make much of a difference as far as recovery,” Boehm says. “Typically, I don’t see the speed come back to the greens until all the sand has worked its way in. While there’s still sand out there and it’s still in the mower blades, there’s not much you can do for speed. I do a lot of rolling at that time.”

Superintendent Kevin Jones doesn’t do anything more than fertilize, either. “I continue with my fertilizer program to promote lateral growth. I know there are programs like include growth regulators, but I don’t use anything like that.”
 

Jason Stahl is a freelance writer based in Cleveland.