Poking Holes into Old Thoughts on Core Aeration

Following “Cultivated Thoughts on Thatch Management” and the results of core verifying our cool season turfgrass fields the week before a stretch of 100 degrees F (38 degrees C), I have spent more time examining the merits of core aeration.  Certainly we as professional managers know the importance of core aeration.  But with time constraints and all the other aeration options available to use today, coring is a bit less used.  After the last few weeks, I am convinced that it is time to buck that trend and get back to the basics of core aeration.

Why do we core aerate?  No- its not just to create overtime for ourselves and our work crews!  Removing the column of soil from the profile makes a direct, open avenue for gas exchange in the soil.  Water is able to infiltrate the profile easier, as well as the removal of thatch/ organic material/ soil that could be undesirable.  Certainly solid tines open columns similarly, but they do so at the expense of compacting the soil around the column.  Now-  do not mis-understand me-  ANY type of aeration/ venting that can be done at ANY time is essential to turfgrass survival,  especially in high traffic field situations.  But pulling cores is the most beneficial of all for gas exchange, thatch removal, and water infiltration into the top of the profile (deep tine aeration is a separate subject for deep water infiltration)

Basic teaching advocates core aeration 2 times a year.  I have spent most of my career buying into that thinking, especially because of the intensity of the process.  By now I am realizing that the benefits from core aeration are sometimes lost in the mess that is created from the aeration process.  By the time the clean up process ends, we find ourselves swearing that we will never do it again.  Last week alone we dulled a set of reels following clean up, then bent 2 reels from debris dropped during the coring and sweeping process.  If I walked into the office this morning and declared we are core aerating again this week, there would be mutiny!

But… outside on the fields… the results are evident from the flush of fresh air into the root zone and proper water infiltration.  Green, strong, healthy turf looks like it was 50 degrees last night- even though we spent the week in extreme heat.

Ironically as I was writing this, my colleague Mr. John Turnour made a similar comments about his aggressive core aeration program at Nationals Park in DC.  He too feels that the results are as dramatic as I do with the flush of air into the root zone bringing an immediate plant response with green, vibrant growth and health.  From a scientific standpoint, I am sure there is more to the response than just the air component- Nutrient availability especially.  I will research this and let you know… I am intrigued to know myself.

In conclusion, the question becomes… how often does it need to be done?  My new goal becomes 1 time a month in the growing season, skipping August unless it catches a cool stretch.  So a total 6-8 times.  That will total a removal of about 40% of the profile (@ 5% per time).  We are at 2 with us to July, so hopefully we can finish at 6.

4 more times-  oh boy- Don’t tell our work crews!!!

1 thought on “Poking Holes into Old Thoughts on Core Aeration

  1. Excerpt from “Everything You Always Wanted To Know About Aeration… But Were Afraid To Ask”.
    You are right on Jerad! When using an SUD (straight up and down) aerator as opposed to a heaving action. A coring tine is preferred unless it’s just for short term “in season” venting. In which case, a core aeration would still be necessary when the weather allows. The complete article is on aerifyinganswers.wordpress.com
    There is also a section on SUD VS. Heaving Action aerators, to ad more explanation.
    I just recently started that site to try to share ideas on what I’ve seen that has worked over the years.
    Thanks again Jerad!
    Bryan Wood 🙂
    With turf managers and golf course superintendents aerifying year-round for different specific reasons these days, here is a brainteaser question to answer: Should you use solid or coring tines? The answer depends first on what style aerifier you’re using and then the problems being addressed.
    Some say that solid tines cause compaction, but they don’t quite have their facts straight. It’s not the solid tine that causes compaction, but the machine it’s attached to. Solid tines are available for both “straight-up-and-down” (SUD) or “heave action” aerifiers. An SUD aerifier with solid tines can do more damage than good. Even with coring tines the SUD technology is obsolete compared to heave action machines. In fact, an adjustable depth heave action aerator is the best all around machine choice.
    A heaving action machine actually slices into the soil profile with a slight lifting action. The tine is in a heaving motion at the bottom of the stroke, thus not creating any hardpan. This creates pour space and increases the cat ion exchange capacity of the soil. This is how it loosens without pulling a core.
    SUD aerifiers with solid tines can be used as a shallow pin spiker (possibly on
    hydrophobic greens or “in season” athletic fields) but are really only good for opening the surface during high stress times, allowing for quick water and air penetration with minimal disturbance to the surface or sub-surface. Again, this is only opening the surface, not relieving compaction. Be careful not to use this method too much or an even more serious problem will develop. The SUD aerifier will create a “sheep’s-foot roller” effect and a really bad hardpan layer in the soil profile. I’ve seen these hardpan layers so severe that not only was there a toxic gas build-up underneath, but the soil also had a toxic chemical layer. So when using SUD aerifiers, whether going deep or shallow, you should generally avoid using solid tines and stick to coring tines for compaction relief.
    Solid tines can effectively be used, adjusted to any depth, with “heaving-type”
    aerifiers – the deeper the better. With little or no damage to the turf, these newer
    designed machines will relieve general compaction as well as relieve the shallow
    hardpan and toxic layer created by the SUD machines. Solid tines ranging from 3/16 to1 inch in diameter and 6 to16 inches in length, and can be used any time the ground has sufficient moisture for penetration. Avoid aerifying any ground (with any style machine) in bone dry condition, or excess damage to the turf and machinery will occur. The old mentality of bone dry “shatter-tining” has been effectively replaced with today’s newer technology.
    Turning to the subject of coring tines, they are used for thatch removal, topdressing, and soil amending. Although 90-95% of thatch removal is accomplished through a good verticutting/topdressing program, an important 5-10% of thatch is removed by pulling cores. This is especially helpful during hot, high stress times when the thatch can become hydrophobic and repel irrigation water. Ironically, in high traffic areas such as the center sections of sports fields or cart path traffic areas, a certain amount of thatch retention is recommended. Most turf managers would love to have some thatch in these areas to help protect the crowns of the plants and prevent players from making a muddy “pig pen” of
    the area during wet conditions.
    Another advantage in using a coring tine is to bring soil to the surface for topdressing. This can be cost affective for multiple athletic fields and fairways.
    Lastly, soil amending through deep tine aerifying with coring tines has been successful for many years now. Through core removal and heavy topdressing, a soil profile can me modified over time without taking the area out of play or spending excessive amounts of money. Care should be taken to either alternate between solid and coring tines, or perform several extra topdressing applications since the densely compacted soil that is being removed is hard to completely replace with a single topdressing. This will prevent a “sinking” affect of the turf area being cored. You may even consider exclusively using solid tines for soil amending since they will generally heal faster and create less mess. Your turf will love you for it, and the channels created with the deep tine make a permanent chimney of sand allowing water and roots to penetrate with ease and flourish.
    As you can see, the choice between solid and coring tines varies with the machine design, the problem being addressed, and the desired outcome. There’s a time and place for both.

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