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Key Takeaways

  • The benefits of putting green aeration are clear, but the disruption associated with traditional core aeration makes it unpopular with golfers and challenging to schedule.  

  • There are many less-aggressive aeration options available today that can allow you to manage organic matter with less disruption to playability.

  • You may need to perform these less-aggressive practices more frequently, but you may also get fewer complaints as a result. 

  • Less-aggressive aeration is easier to accomplish with limited labor resources and easier to fit into increasingly unpredictable weather windows.

Putting green aeration is one of the most scrutinized practices performed on golf courses. Even if golfers, department heads and decision-makers recognize that putting greens should be aerated, the timing often becomes a point of contention. From an agronomic standpoint, superintendents usually want to aerate when grass is healthy and growing well to expedite recovery. However, the perfect agronomic timing often conflicts with the golf calendar, so compromises must be made. Factor in concerns about shifting weather and deciding when and how to aerate the greens is not so cut and dry anymore.

The benefits of aeration are clear. Managing organic matter is obviously very important for maintaining healthy turf and quality playing conditions. Creating channels in the soil profile – either by removing a plug or using a solid tine – will improve gas exchange. Grass roots need sufficient oxygen and will suffer if growing in an environment where gas exchange is limited. Regularly opening the soil profile is one foundational block of a successful management program. 

Compaction relief is another principal reason superintendents aerate. Relieving compaction will improve rooting and gas exchange, which makes for overall healthier soils and playing surfaces that are able to withstand fluctuations in weather and pest pressures. Interestingly, compaction relief seems even more important since golf started booming again in 2020. Improving soil health and increasing pore space via aeration has always been important, but it’s even more so when your course experiences a sharp increase in rounds played. 

So, with all these benefits, how can superintendents keep aeration in their annual program while minimizing the headaches of scheduling and keeping golfers relatively happy? An increasing number of superintendents are utilizing less-aggressive aeration practices to find this balance. There are more options for aeration equipment and tine styles than ever before, and some are very low impact.

Using less-disruptive aeration methods has the obvious benefit of minimizing the impact on playing conditions. It’s also a great way to reduce risk given increasingly unpredictable weather. The changes we are seeing in seasonal weather patterns is a big reason for the increased interest in adjusting tine size, frequency or type of aeration to lower-impact options. Superintendents and golfers do not like when aeration holes recover slower than anticipated. Cooler-than-normal spring weather that lasts later into early summer can delay recovery until soil temperatures increase to the point where grass is actively growing. By the same token, hotter-than-normal summer weather that lasts later into the fall can narrow the window for aeration and recovery later in the year.

Another reason to consider less-aggressive aeration is labor shortages. A lot has been written about the labor challenges facing the golf industry, and there doesn't seem to be a clear way out. For this reason, and sometimes this reason alone, decreasing the aggressiveness of aeration is necessary just so the procedure can be completed at all. 

Lastly, there is growing debate among industry professionals and researchers about whether core aeration is necessary to manage organic matter. This is an interesting question, and something to think about as superintendents balance managing organic matter and maximizing playability.

What Is “Less-Aggressive” Aeration?

There is not a definition of less-aggressive aeration in the dictionary. In fact, defining aeration aggressiveness is subjective to the audience. For example, if your course aerates twice per year there are likely some who think that is fine and others who think it is too much – i.e., too aggressive. There are also superintendents who aerate once per year and hear that has too much impact. For the sake of this article, I’m going to consider twice-annual core aeration standard and anything more than that with a tine size larger than 1/2 inch “aggressive.” 

Another subjective factor regarding the aggressiveness of aeration is how long it takes for the greens to recover. It seems that no matter how long it takes for the greens to recover, anything beyond a day or two gets placed in the aggressive category as far as golfers are concerned. While that is a bit extreme, one of the principal reasons to consider less-aggressive aeration is reducing the time for recovery. 

The following sections will highlight some “less-aggressive” approaches to aeration that can potentially allow you to realize the benefits of this practice with fewer headaches and less disruption to play.

Micro-Tines

With the number of tools available for aeration today, including the release of micro-tines like Ninja Tines or Samurai Tines, superintendents have options. Depending on your goals for surface disruption, you can now find any number of tools to accomplish that while disturbing golf less. For example, using the International Sports Turf Research Center (ISTRC) tine-size guide one can see that twice-annual core aeration with 1/2-inch tines on 2-inch by 2-inch spacing removes about 10% of the surface annually. If you maintain one core aeration for 5% disruption and add one ultra-small-tine aeration once per month during the growing season that will equal an additional 5% or more of surface removal depending on how long your season is. This translates to the same annual surface removal of two standard aeration events with less disruption to playing conditions.

The benefits of using ultra-small aeration tines are quick recovery and virtually no disruption to play. Hearing this gets golfers’ attention when discussing the benefits of these small tines. Ultimately, superintendents can accomplish their goals of 10% or more surface removal annually and golfers are happy that they get good putting greens for longer during the season. 

Another benefit of more reliance on micro-tines is that cleaning debris following aeration is much less labor intensive than cleaning larger cores (Jacobs, 2020). Because the holes are so small, sand should not be added to fill them. Rather, cores are removed and then normal maintenance returns. The holes will disappear in a day or two after normal mowing and rolling practices. The cleanup process also doubles as a light topdressing application. As the small cores are blown into piles and collected, sand from the plugs inevitably detaches and is returned to the putting surface. 

Deep Linear Aeration

Another less-aggressive option is deep linear aeration with a Graden or similar tool. This removes a lot of material, more so than core aeration, but it has been said that despite the amount of surface disruption there can be less impact on playability because the lines don’t influence ball roll as much as holes do. This option is often used to replace one core aeration in a year to maximize thatch removal with less disruption to play. 

It is debatable whether deep linear aeration is less aggressive than traditional core aeration because the amount of material removed is so much greater than any core aeration program deployed on a golf course. In fact, for organic matter management alone one could reasonably replace one or all core aerations with a single Graden treatment. If a single deep linear aeration is perceived by the golfers at your course as being less aggressive than a single core aeration, and if that linear aeration eliminates the need for a second core aeration to achieve your organic matter management goals, then this approach could be a great option.

Solid-Tine Aeration With Regular Topdressing

The last option for less-aggressive aeration, and perhaps the most researched and discussed recently, is solid-tine aeration. This process involves using a machine with solid tines to create holes in the soil of the putting green without pulling a core. The holes are typically smaller in diameter than those created by hollow tines, and even if they aren’t smaller they typically heal quicker and there are no cores to clean up afterward. Here are some benefits of a solid-tine aeration program:  

Increased Drainage: Solid-tine aeration can improve drainage and water infiltration. When soils become compacted, it can prevent water from draining properly, leading to standing water on the surface and potential turf decline. By creating small holes in the soil, water can flow through and either move away from the surface where it is most damaging or if the greens have internal drainage, find those drain lines more rapidly. 

Reduced Thatch: Thatch is a layer of living and dead organic matter that can accumulate just under the putting surface. If left unchecked, thatch buildup can prevent water, air and nutrients from reaching the turf roots. Solid-tine aeration can break through thatch, exposing it to air and accelerating decomposition.

A major component of thatch management when using solid-tines instead of pulling cores is sand topdressing. For a solid-tine aeration program to be successful, there must be a commitment to topdressing. A study at the University of Nebraska showed that tine type and frequency of aeration were not as important in organic matter management so long as sufficient topdressing is applied (Gaussoin et al., 2014). To improve efficiency and ensure sand moves deeper into the soil, topdress the surface first followed by solid-tine aeration to force it down. I have found this to be the best way to eliminate layering and improve efficiency.

Reduced Costs: Solid-tine aeration is a cost-effective way to maintain the health of putting greens. Compared to using hollow tines, solid-tine aeration is less expensive and can be done more frequently without being as disruptive. The time and labor savings that comes with not having to clean up cores is significant. This allows for more consistent maintenance of the putting greens, which can improve playability and lower maintenance costs.

Less Time: Unlike hollow-tine aeration, solid-tine aeration does not remove any material. This means it can be done quickly and easily and maintenance can resume right after the treatment. All the greens on a course can usually be aerated, topdressed and brushed in less than a day when using solid-tines. Compare that to hollow-tine aeration, which can take several days depending on the equipment and labor available for the cleanup process.

The Question of Compaction: Some would argue that solid-tine aeration contributes to soil compaction at the bottom and edges of the hole. While this could be a plausible argument in a clay or silt soil, there is little evidence to support the idea that compaction is increased in a sand-based green. In general, the dilution of thatch and organic matter at the surface provides enough benefit to turf health and playing conditions to outweigh any risk of soil compaction, however small (Gross, 2019). If you are concerned about creating a compacted layer through repeated solid-tine aeration, one possible solution is to vary the depth slightly from one event to the next to reduce any risk there might be. Occasional deep-tine aeration is another way to reduce the risk of a compacted layer developing.

Conclusion

There are many valuable tools for aerating putting greens that are not traditional hollow tines. This isn’t to say that a traditional hollow-tine program is not, or cannot be effective – they have been for decades. What this means to the practitioner is that if you are wondering if there is another way to accomplish your putting green aeration goals with less disruption, less downtime and lower costs the answer is…perhaps. There are options available and research exists that supports the potential benefits. It is up to each superintendent and their facility to decide if a less-disruptive method is better than what you are doing already. 

References

Gross, P. (2019, 4 October). Is solid-tine aeration right for your greens? USGA Green Section Record, 57(10).

Jacobs, P. (2020, 7 August). New trends in aeration and organic matter management. USGA Green Section Record, 58(15).

Schmid, C.J., Gaussoin, R.E., Shearman, R.C., Mamo, M., & Wortmann, C.S. (2014). Cultivation effects on organic matter concentration and infiltration rates of two creeping bentgrass (Agrostis stolonifera L.) putting greens. Applied Turfgrass Science, 11, 1-7.