When it comes to turf aeration, professionals define quality by quantity, depth and pattern.

Aeration, the process of penetrating the turf, thatch and soil to reduce soil compaction, is vital to the life-cycle of turf grass and improves water retention, air circulation and nutrient absorption to the grass root system to promote new or deepening root growth. Aeration is not just poking holes on the ground. There is a science to it.

Breaking the Surface

There are several types of mechanisms used to penetrate the soil. Vertical slicers or slit aerators utilize thin blades to reduce surface area compaction. Spike tine aerators utilize solid shaft tines to relieve the compaction found in transplanted grasses like sod that have a relatively shallow layer of grass root and soil applied over sandy or porous basins. Core tine aerators utilize hollow shaft tines that remove a plug or core of turf, thatch and soil to instantly relieve soil compaction.

Quality of Core is defined by professionals as a mix of core quantity, proximity and depth.

In a national survey of over 5,000 landscape contractors, turf care professionals, and golf and sport field superintendents in the United States conducted in the fall of 2015,

91% of the respondents noted that they utilize core tine aeration over all other available methods.

With the majority of professionals utilizing core aeration as their primary turf aeration mechanism, there are numerous core tine aerators on the market to consider. From the tine delivery system to tine spacing and depth control, the right aerator can make all the difference in core quality.

Defining Quality of Core

Professionals surveyed determined quality of core to be a combination of three factors:

• Quantity of Cores
• Depth of Cores
• Core Pattern

While all three factors were considered statistically significant in the final survey results, landscape contractors put more emphasis on core quantity as a productivity factor, where turf care professionals and superintendents put more emphasis on depth and core pattern.

1. Core Quantity

Core quantity is determined by the number of tines, tine spacing, rate of operation and (to some extent) the tine drive mechanism. There are two tine drive mechanisms most commonly used in powered core aerators: tine wheels that rely on weight to penetrate the soil and reciprocating tine rods that rely on force to penetrate the soil.

Tine wheels are circular disks spaced along a rod (or shaft) that have numerous core tines mounted or welded to them fanned out around the wheel. The tine shaft is lowered to place the tines on the soil surface. Proper depth is achieved as the unit is propelled forward. The speed at which the unit travels does not affect the quantity of holes it is able to produce. The number of tines and distance between the tines on the wheel and the number of wheels and distance between them along the shaft determines the quantity of holes the unit can produce in a single swath.

Tine rods are mechanically or hydraulically driven in and out of the ground. The quantity of holes produced on tine rod units depend on the rate in which they reciprocate and the speed at which the unit is being propelled. While some tine rod units are capable of hundreds of tine reciprocations per minute, the distance between each tine rod along the shaft is set. If the unit only has four tine rods set six inches apart, you will still need to do a couple of passes to produce a proper core pattern. While core quantity is a productivity factor, it is but one factor to consider.

2. Core Depth

Proper core depth is vital in alleviating soil compaction. Achieving a depth of two to three inches is sufficient to relieve most soil compaction and give the root system new room to grow. The compaction area in turf grass soil runs about an inch and a half deep.

Accounting for an average half inch thatch layer, you will need to aerate at a depth of at least two inches to relieve soil compaction. And you should allow an additional half inch or so to create a growth pocket to promote deeper existing root growth.

Heavy traffic areas with deep rooting systems may require deeper aeration from time to time. And, depending on the depth of irrigation and conduit on the property, some areas may only tolerate shallow aeration. As such, using an aerator that allows for easy depth adjustment provides flexibility. The key is in knowing the turf conditions and terrain before you start aerating.

Consistency Counts

It is important to utilize an aerator that allows you to set a maintained depth or at least to lock in a maximum depth. Inconsistent core depth can be a problem with aerators that maintain tine depth hydraulically. Stand-on aerators for example, utilize hydraulic pressure to drive and maintain tine depth. However, there is no way of knowing from the pressure gauge exactly how deep the tines are penetrating. Some newer units now offer depth-stop settings to ensure the tines do not exceed a set depth.

Tine depth control is necessary on a stand-on aerator as hydraulic pressure varies. Look for a unit that allows you to lock in settings. Photo: Classen

Regardless of the unit you choose to use—walk-behind, stand-on or tow-behind—core depth is something you’ll want to monitor. Make a first pass and pick up a few cores to make sure you are achieving the depth needed and that you are maintaining consistent depth. A good rule of thumb is to simply use your thumb to measure the length of the core pulled. The average adult thumb length is 2½” (female) to 2¾” (male) from the first knuckle to the tip. That measures up nicely with the two- to three-inch core depth professionals recommend.

3. Core Pattern

Core pattern is considered by many turf care professionals to be the most important factor. The proximity of the tines to one another, not just in the distance between the tines along the shaft but also the distance from one tine tip to the next on the wheel or the distance traveled before the tine rod once again punctures the ground is the core pattern.

In core aeration, there are two primary core patterns: straight line and staggered. Both patterns will aerate the turf grass effectively so long as the holes are spaced evenly apart in any direction. Professionals suggest a two- to three-inch tine pattern. When in doubt, test a small area in a crisscross pattern and measure the distance between the holes with a ruler or your thumb.

In general, quality of core is a combination of quantity, depth and proximity. Using aeration equipment designed with these three key attributes in mind will provide the best quality of core result for the turf and your aeration customer.

Classen® walk-behind, stand-on and tow-behind aerators provide the best Quality of Core® in the industry. Learn more at www.classenturfcare.com. Classen® and Quality of Core® are registered trademarks of Schiller Grounds Care, Inc.

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This page was produced by North Coast Media’s content marketing staff in collaboration with Classen. NCM Content Marketing connects marketers to audiences and delivers industry trends, business tips and product information. The Landscape Management editorial staff did not create this content.