When clothing manufacturers first introduced “wicking” fabrics made of mesh-like materials, it was – literally – like a breath of fresh air. Athletes were thrilled. Instead of heat and sweat building up under uniforms, they could finally “breathe” during games, leading not only to greater comfort but also to increased performance.
It turns out that a little ventilation goes a long way.
Consider that the next time you’re debating whether it’s worth aerifying your sports field.
“Fortunately many people do understand the importance of aerification, because they realize the many turf benefits, and the safety benefits, from it,” says Jon Mitchell, who operates River Region Sports Fields, an athletic field contractor based in Millbrook, Alabama.
Typically, when it comes to high school and rec fields, Mitchell’s company performs two aerations per year.
“We usually go in right after the [spring] season ends, in the middle or end of May, and do an aggressive core aeration with 2-by-2-inch hole spacing. Our goal is to punch a bunch of holes, pull a bunch of cores, and then sweep up the organic material,” Mitchell explains. He prefers to sweep up the cores to remove as much organic material as possible from the material, as clippings are usually not collected during the mowing of most high school and rec fields.
“We use a Toro ProSweep to pick cores, and also a Toro VersaVac (verticutter/ vacuum) and we can raise the blades a little bit and vacuum with it – it’s very fast to use that,” Mitchell says. “Then we topdress to try to amend the soil a little bit and reduce the thatch.”
Typically, Mitchell uses a USGA mix and tries to address somewhat the existing rootzone mix on the field – for example, on a field with a more native soil rootzone mix, he will try to use a coarser sand to open up the pore space a bit and help promote water infiltration.
“Aerification by itself is great, but at least in the soils in our area, you really need to do a good sand topdressing program in combination with the aerification,” agrees John Braun, owner of Professional Grounds Management Services, a sports field maintenance contract firm based in Houston, Texas.
Soil-based fields tend to tighten and compact over time, and the addition of sand helps to make the field more pliable and opens the pore spaces, Braun says. He uses a clean masonry sand with a very low percentage of organic material.
Braun typically opts not to collect the cores following aerification, because leaving them on the field maintains some organic material and eliminates the need to apply organic soil amendments.
An aggressive approach
Braun says he sees many sports turf managers who use drum-type aerators that pull cores every 5 inches or so, as well as using knife- and vibratory slit-type (shatter tine) equipment. “In my opinion, that’s not nearly as effective,” he says. When using aerators with wider spacing, some will go over the field three or four times, which can accomplish the same thing as the 2-inch spacing that he uses, but it’s more time consuming.
“Too many people try to do aerification in an easy way with less disruption by doing a solid tine or a knife-type aerification. But what I subscribe to is that you want to pull a core – that’s a true form of aerification,” Braun says. “We tend to be a lot more aggressive…we pull a hollow core about every 2 inches (on 2-inch centers). It’s aggressive, but you’re both relieving compaction and allowing a lot more air down into the soil.”
Another benefit of being more aggressive with core aeration is that you can do it less frequently, notes Braun. Instead of using a drum or slice-type aerator four, five or six times a year, aggressive core aerification can be effective with less frequency. “Our most aggressive program, for football and soccer fields, is twice a year…that’s usually plenty,” he explains. On baseball and softball fields that don’t see as much traffic, once a year is usually adequate, Braun adds.
When it comes to fields that haven’t been aerated regularly, Michael Gilmore, president of Growing Solutions, Inc., which provides aeration and other turfgrass services to sports fields and golf courses throughout the Mid-Atlantic region — typically prefers to begin with deep tine aeration using 0.75-inch-by-12-inch solid tines. “What we’re trying to do is break up that surface tension and get some oxygen going through the soil, to try to relieve the compaction,” he explains. “Then, depending on the other issues we see on the field, we’ll develop a conventional core aerification using 0.75-inch-by-4-inch tines.”
Gilmore says he has also begun doing more vertical aeration in recent years; he uses an Imants Shockwave “rotary decompactor,” which uses knives to fracture the soil and help it drain. While he started using it only in extreme situations, he says he is now using this machine more regularly. “On a lot of fields, the biggest issue is surface drainage; anything you can do to get water off the surface is a huge help,” states Gilmore.
Regularly scheduled program
Growing Solutions provides aerification services for Major League Baseball’s Baltimore Orioles and the Washington Nationals, as well as a number of minor league baseball teams, colleges and prep high schools. “They are all pretty regularly scheduled,” Gilmore says.
When the company is called in by a sports field manager looking to address a problem, they typically also decide to sign up for a regular aerification program to help relieve it and prevent it from reoccurring. “When we get called in, it’s often because they’re having drainage issues and compaction issues and the middle of the field is getting beat up more quickly and more severely than the rest of the field,” he says. “At that point, they’re kind of at a loss because of the compaction and the lack of water moving away from the surface. And they start to see the value of aeration.”
While results can often be seen soon after aerification (“literally in a day you can sometimes see the field have a little bit more vibrancy,” Gilmore says), it takes more than a couple of times “to get you where you want to be – especially if you haven’t done anything in a couple of years,” he stresses. “The more you do it, the better off you are.”
While professional fields are often aerated more frequently, Gilmore says it’s common on college and high school fields to do deep tine aeration annually, followed by core aerification after a season is over. Contracting for these services is a popular approach, especially for fields that don’t have the budget to purchase expensive aerification equipment.
While field schedules can’t always be controlled, Braun prefers to aerify in June rather than waiting until August, which is right before school fields will be in use. “We try to schedule a second aerification during Christmas break, when kids are out of school and there are no sports activities,” he adds. “And that spaces out the aerifications to every six months, which is ideal.” (He notes that this schedule works in the Houston area, where the growing season slows down but doesn’t really stop in the winter; obviously timing of aerifications will depend on local climate.)
River Region Sports Fields performs deep tine and hollow core aerifications, and also uses an Air2G2 aerification machine during sports seasons. With core aerations, “we use a smaller tine than a lot of people do on sports fields,” says Mitchell. Instead of 0.75-inch tines, he prefers smaller 0.625-inch tines, similar to what would be used on golf greens.
“That reduces the surface disruption – instead of bigger, gaping holes we produce smaller holes. That lets us use a tighter spacing, as well, so we can get more holes.”
Especially during spring and fall sports seasons, when it tends to be rainy and wet in that part of the country, he often opts for the Air2G2 method. “That doesn’t cause much surface disruption. We can get in with the Air2G2 machine and pump some air in the ground to help water infiltration and to relieve compaction and nobody even knows we’ve been there,” says Mitchell.
Just do it
Sometimes people may be afraid to aerate, worried that they may do something wrong that will damage the field. But Gilmore says the biggest mistake he sees is people simply waiting too long to aerate, or not doing it frequently enough.
He says it’s important to use the right aerification equipment for a given field; the decision on how aggressive to be with tine sizing and spacing can be influenced by whether the root structure on a given field is deep or shallow.
Timing is another consideration — fields tend to be more receptive to aerification in the spring and fall, says Gilmore. Still, he says he does quite a bit of aerating in the summer using solid tines; in those cases, he tries to do the work during cool spells, or during cool parts of the day, when the field has a little more vibrancy.
“You need to be smart about temperatures; we try to stay away from it during hot periods,” Gilmore explains.
The moisture present can also impact aerification.
“If you’re using a solid tine, you can go in after a rain. But if you’re pulling cores, it will make mud,” he notes.
Braun has found that the two reasons sports field managers, particularly at schools and rec parks, don’t aerify more regularly both relate to equipment: “The equipment is expensive. And it is difficult to maintain.” But he makes the point that aerification helps not only improve the health of the turf, but also the playability of the field.
“You’re trying to take the hardness out of the field, and you can definitely feel the difference [after an aggressive core aerification],” he says. “You want the field to have some give, so when the player goes to plant their foot, they’ve got something to plant into and they don’t just slide over the surface of the turf.”
There are times when River Region Sports Fields is called in to aerate a field that has never been aerated before. “We use a VertiDrain 7120 as our big aerator to pull cores,” Mitchell says.
“That is a big, heavy machine, and there’s not a whole lot of places that will bounce it around, but you can definitely feel the difference when you’re on a field that’s on a regular aerification program versus one that’s just aerified occasionally.”