When budgets get tight and manpower runs short, every sports turf manager has to prioritize about what has to get done (mowing, striping, maybe fertilizing) and what jobs could be put off. Because it can create a mess and the benefits aren’t instantly recognized, aeration may often be one of the jobs that gets pushed into the future. That’s a bad idea, according to turfgrass professionals. Aerification is critical to the success, and even the safety, of sports turf in many different ways; it’s almost always better to increase your aeration frequency rather than skipping over it.
“A lot of people know the importance of aerating – it keeps the soil from getting compacted, it gets oxygen down into the rootzone, it helps with drainage, and on and on and on. I think the biggest struggle is getting the cost of it included in their budget,” says Mike Cippera with Odeys, a sports field construction and maintenance firm that works across the Midwest.
With his location, the times Cippera prefers to aerate are May and late August to early September. “They’re ideal because the turf is growing strongly and there’s less disruption. There’s quicker recovery then, because aerating is a little stressful on turf,” he explains. “If somebody is going to only aerate once or twice per year, that’s the window we try to put them into.”
For those who can only aerate once, he would advise doing it in the fall. That said, Cippera recommends aerating “whenever you can. You really can’t over-aerate. There’s really not a bad time to aerate, there’s just better times to do it.” That’s fortunate, he notes, because field schedules sometimes dictate when aeration can take place.
Odeys uses four different types of aerators on sports fields: a Toro ProCore 648, a 4-foot-wide walking unit he says is used mainly on baseball infields and aprons, goalmouths, sidelines and other small areas; a tractor-mounted Toro ProCore 864; a Terra Spike XP deep-tine aerator from Wiedenmann; and two AERA-vators from First Products.
“We aerate to the compaction level of the field,” explains Cippera of how he decides which unit will work best on a given application. “If it’s compacted mainly in the top 3 or 4 inches of the field, we’ll use one of the ProCore’s, which go down to a maximum depth of about 4 inches. If there’s deeper compaction, we’ll go with deep-tine.” Most of the fields he works on are native soils with a relatively high clay content, so even with a deep-tine aerator it’s rare to get much deeper than about 8 inches, he notes.
When he has to aerate during the summer, Cippera will often switch his ProCores over to solid tines to minimize disruption. “We’ll run needle tines or star tines or bayonet tines on those. It doesn’t do much to relieve compaction, but it helps with drainage and helps to get some oxygen exchange in the rootzone,” he says. When temperatures get really hot, say over 95 degrees Fahrenheit, he prefers to not pull cores to avoid further stressing the turf.
Cippera will often overseed in conjunction with the aeration. “For our climate, mid-August to mid-September is a good seeding window, so it works out well,” he notes. “But, depending on conditions, we’ll do spring and summer seeding. And we do quite a bit of dormant seeding on football fields, because the seasons run so late. If it needs to be done, it needs to be done.”
“Compaction is the biggest reason for aeration on a sports field,” says Adam Cunningham, construction superintendent with Lohmann Sports Fields (http://www.lohmann.com). He recalls aerating one field in Arizona that was as hard as concrete. “When you have a field like that, it’s best to do solid-tine aerating, because the tines won’t break or bend as much [as coring tines],” he explains. On that particular field, he aerated three times with solid tines before he was able to relieve enough compaction that he could go over it with 1-inch coring tines. “Then we topdressed it. The field got better and better every time we did it,” he says.
The type of aeration also depends on whether or not the field is in use, says Cunningham. “The coring tine, obviously, makes a mess. But when you’re not in season, the coring is good to open everything up.” The one exception, he notes, is during the heat of summer, when core aerating can jeopardize the turf, “In the heat of the summer, if you don’t have irrigation, it’s hard to open that ground up because it dries out quicker,” he explains.
Cunningham says that almost every time he core aerates a field, it’s in conjunction with topdressing. “We core aerated, topdressed with sand and some compost, and then dragged everything in,” he recalls of one project completed on a high school field last year. “It’s also possible to topdress after a solid-tine aeration,” he emphasizes. “Some people don’t think there’s a benefit to doing that, but you’re still opening a hole and fracturing the ground, and you can still get sand in that hole.”
“For us, aeration is mainly about managing compaction on fields,” says James Compau with AAA Lawn Care in Michigan, which provides aeration and other turf maintenance services at sports facilities around the state. “The number one issue we face on the athletic fields we manage is overuse. There’s so much traffic on these fields that compaction becomes a problem, and we do our best to manage that,” he adds.
Aeration not only helps to reduce compaction, but also improves the overall playability of fields, says Compau. “Aeration allows the turf to fill in and recover once the use goes away at the end of the season,” he explains. From that standpoint, there are safety ramifications to aerating. “I would say, overall, if you have a well-developed turf and you have a high percentage of cover, that field is safer than one that is all dirt. It’s just one part of the overall, but it’s an important part,” Compau stresses.
He points out that in Michigan sports turf gets used in the spring even before the grass comes out of dormancy, as is true in many northern climates. “So I always try to look ahead and to plan around seasons. For fields that are multiuse and have fall sports and spring sports, I make sure to aerate right after the fall season. In that late-fall aeration, I’m trying to deal with compaction issues that would show up in the spring,” he explains.
In those cases, once the spring season is over, usually late May or early June, Compau tries to immediately aerate the field again while also overseeding. “Personally, I do very little core aeration,” he notes. Instead, he uses an AERA-vator. “That’s my number one tool; I really like it because I get the depth I want – 3.5 inches – and it really fluffs the soil nicely. A core aerator, a lot of times, won’t get the depth,” states Compau. “It also works very well with overseeding, so I can save my customers money by not having to bring out a slit seeder. I can do both things at once: relieve compaction and work seeding into the ground, and get it done in one pass.”
James Compau with AAA Lawn Care recommends creating an aeration schedule, and then sticking with it.
Photo courtesy of AAA Lawn Care.
Compau also does a significant amount of topdressing, and adds that the AERA-vator helps him accomplish this task. “If you’re doing sand cap topdressing, I don’t like to bring native soil on top of sand topdressing. The AERA-vator doesn’t do that; it’s a solid tine and it vibrates,” he explains. “Some people like to core aerate and then topdress, but I prefer to do it a different way.” In most cases, he puts the topdressing down on the field, overseeds, and then goes over everything with the aerator.
Deep-tine aerating is another regular practice for Compau, often in the late fall. He uses a Toro ProCore SR70 that goes down about 10 inches. “You’re really limited to the depth of the drainage and irrigation lines,” he observes. “A lot of people can’t afford to deep tine every time they aerate a field; it’s more expensive just because there are more moving parts and the tines are expensive, and it takes longer. But you need to do it to get the depth and really smash through that hardpan. It helps with drainage and compaction.”
Most people, says Compau, don’t aerate enough. “I would like to have a lot more frequency on the fields I manage than I get. A heavy-use, multipurpose field, I would like to aerate four or five times a year, but they probably only have the budget for two or three,” he explains. Bringing in an outside contractor can help make aerating more feasible, he notes, because the sports facility doesn’t have to purchase the equipment or tie up its staff to get the job done.
Whether you do the aerating in-house or call in a specialist, Compau recommends creating a plan and then sticking to it. “Follow your plan. I’ve seen fields that have been neglected and haven’t had their aerations done, and the fields just keep going backwards and backwards,” he says. “When you’re dealing with high-pressure schedules and overuse, it’s a lot harder to bring those fields back than it is to just continue to maintain them properly.”