# Mechanical Aeration: ATY vs Everyone Else



## kevreh (Apr 3, 2018)

Finding this new variation of the ATY forum has been cool. There's been one thing in the back of my mind as I watch videos by the likes of Matt from Grass Factor, Pete from GCI Turf and Allyn from Lawn Care Nut. They all recommend core aeration while ATY has always been against it. Why is there such a variance in opinion? Has TLF stuck to that mantra, or are things changing? I find common themes between the ATY and those guys, but this topic is pretty black and white.


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## social port (Jun 19, 2017)

As far as I can tell, there is no mantra around the practice at TLF. We have big believers in annual practice, while others opt for core aeration only occasionally or by circumstance, such as when heavy equipment has been used on the lawn.

If I see a trend beyond at all (and I'm not sure that I do), fescue enthusiasts, especially in the transition zone, practice annual core aeration. But of course, plenty of KBG folks from all around use double and triple passes as part of their yearly program.


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## g-man (Jun 15, 2017)

My thoughts:

Pros
Proper aeration with multiple holes will provide oxygen to the soil.
Breaks the thatch layer of the lawn
Reduce mechanical compaction
Increases rooting
Allows adding compost (organic matter) into the soil

Cons
The exposed soil from the plugs makes an environment that could grow weeds
Breaks the PreM protection in the soil
In a healthy soil with good organic content and earthworm it is not needed, since the worms will aerate for you.

Common mistakes
The holes have to go deep (2-3 inches) and 20-40 holes per square inch. Most machines can't do this without multiple passes and a very moist soil.
The lawn has to be actively growing (Spring or Fall) for it to recover from the damage.

There was a thread last year about it with a lot of good points. I can't find it.

By the way, I do aerate sometimes in the spring.


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## Green (Dec 24, 2017)

Mechanical aeration is often not actually necessary (much compaction is electrochemical), and it can bring up weed seeds or screw up the soil if not needed or not done properly.

I've noticed that everyone is jumping on the bandwagon of chemical aeration, organic matter, and biostimulants lately. A few years ago, no one made videos about it. Today, biostimulants are a huge thing.

Some guys have built their programs around core aeration, because it works for them in their situation. An example is Peter of GCI Turf. It depends on the soil type in the area, and a whole host of other factors. He explains why.

There is no "aeration is good or bad". I do it once in a great while if/when the situation calls for it (mechanically compacted soil; major overseeding). But it's often not needed, and is labor intensive and/or expensive.

We did not get more than 1/2 to 1-inch cores, even though I gave the lawn a good watering the night before. It still helped loosen things up and create room for seed though.


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## kevreh (Apr 3, 2018)

Looks like a lot of times when Pete aerated he drops seed. Guess it depends if customers want to pay for it. But the point is he probably sees better germanation with some seeds going down the holes. So over seeding plays a roll. Of course we're talking about TTTF. With KBG overseeding isn't as necessary.

I aerated last fall and think it tilled up more weeds then normal. Maybe I'll make sure I use pre-m in the fall next time.


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## thegrassfactor (Apr 12, 2017)

One of the other reasons I like mechanical is getting phos, lime in the soil profile. I don't use a ton of either of them, but it's a great tool to get them where they need to be.


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## Green (Dec 24, 2017)

thegrassfactor said:


> One of the other reasons I like mechanical is getting phos, lime in the soil profile. I don't use a ton of either of them, but it's a great tool to get them where they need to be.


That's a good point. Btw, it's great that you are so into the science behind soil and grass and that you explain it in your videos. I can count on one hand the number of people I interact with online who have that level of understanding and interest in the subject, and are willing to teach/help the rest of us. Btw, Pete from GCI mentioned you in one of his newest videos recently if you haven't seen it yet. He said he didn't think you would mind...In any case, it was a pretty big compliment...he basically said that your level of knowledge and interest in the science was light-years ahead of almost everyone else.


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## ryeguy (Sep 28, 2017)

Check out the thread from last year where I basically asked the same thing:

Are there any studies showing the efficacy (or not) of aerating?

Lots of great discussion in that thread. I believe this is the one @g-man was referring to above.


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## pennstater2005 (Jul 17, 2017)

If I did an overseed I would either use a true disc/slice seeder.....









If I couldn't find that to rent then I would consider mechanical aeration.

That machine above is only a cool $6500 for anyone interested.


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## Ware (Jan 28, 2017)

I smiled when I saw this thread title because I know what would happen if "TLF" was used in a thread title on ATY.








Just thankful for what we have going on here. :thumbsup:


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## Sinclair (Jul 25, 2017)

LCN, GCI, and Grass Factor have all been starting to experiment with chemical aeration.

Grass Factor has a side by side trial happening at the moment.


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## ryeguy (Sep 28, 2017)

Sinclair said:


> Grass Factor has a side by side trial happening at the moment.


I wish he did a control though. If the 2 plots end up looking the same we can't draw conclusions from that.


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## kevreh (Apr 3, 2018)

Ware said:


> I smiled when I saw this thread title because I know what would happen if "TLF" was used in a thread title on ATY.
> 
> 
> 
> ...


Ha! :beer:


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## GrassDaddy (Mar 21, 2017)

My two experiences.. we core aerated the church and two weeks later the holes had filled in. In my backyard my screwdriver couldn't go down an inch but then using soap and yucca it could go down a foot.

So I'm a fan of core aeration when applying something like seed but otherwise I see it as a temporary solution. Golf courses and Fenway etc will core aerate and then topdress with sand but residential we never see that recommended.


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## kevreh (Apr 3, 2018)

ryeguy said:


> Check out the thread from last year where I basically asked the same thing:
> 
> Are there any studies showing the efficacy (or not) of aerating?
> 
> Lots of great discussion in that thread. I believe this is the one @g-man was referring to above.


Thanks for that link, lot of good info.


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## g-man (Jun 15, 2017)

GrassDaddy said:


> core aerate and then topdress with sand but residential we never see that recommended.


I topdress with compost instead of sand.

I really like the science behind the Air8 product that thegrassfactor described in a video. I wonder if it would be even more effective after core aerating too.


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## Ridgerunner (May 16, 2017)

Ware said:


> I smiled when I saw this thread title because I know what would happen if "TLF" was used in a thread title on ATY.
> 
> 
> 
> ...


 :thumbup:

Lotsa luck to those trying liquid aeration. :roll:


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## stotea (Jul 31, 2017)

I'm not going to regurgitate anything others have already said, but I will add a few things I've come across that I don't often/ever see mentioned here or similar places online.

1. Can anyone direct me to quality, empirical data that supports any kind of effectiveness of liquid aeration products? All I ever see is people claiming how great it is based on theory/speculation. In fact, every university or independent source I've read says it MAY be beneficial, at best.

2. I read one independent study that looked at the effectiveness of mechanical aeration on putting greens. The overall results showed little to no material difference vs the control.

3. I read another source that stated while mechanical aeration is generally good for residential turf, it also has a tendency to create what is essentially an underground layer of compaction that occurs at the depth of the removed cores. Thus, the problem of compaction is not eliminated but essentially moved into the subsoil. Fortunately, this can be alleviated with deep-core aeration. However, it may be difficult to find someone with the appropriate equipment and willing to service a residential lawn.

I'm not trying to imply that aeration is bad or not worthwhile. I just want to bring up some points that I rarely see discussed, if ever.


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## Greendoc (Mar 24, 2018)

GrassDaddy said:


> My two experiences.. we core aerated the church and two weeks later the holes had filled in. In my backyard my screwdriver couldn't go down an inch but then using soap and yucca it could go down a foot.
> 
> So I'm a fan of core aeration when applying something like seed but otherwise I see it as a temporary solution. Golf courses and Fenway etc will core aerate and then topdress with sand but residential we never see that recommended.


That is because on golf courses and sports fields, they are sand topdressing to dilute organic matter in a sand based growing media. There, cores are pulled, then sand is brushed into the holes. That is done several times a year. Small amounts of sand, as in from one core aeration+topdressing can turn clay soil into a brick rather than increase porosity. If I have to deal with a lawn on bad soil, remembering that I have warm season grasses mowed low, I prefer to skip the aeration and simply add multiple layers of sand causing the grass to re establish its roots in the sand layer. Warm season grass will do this. I do not think cool season grasses with the exception of Bent Grass will.

My experience with seed broadcast after a core aeration has not been that positive. Holes are normally too far apart to make an impact. I prefer slit seeding. In a warm season area, that is the same Verticut machine without the seed hopper. Its purpose is to cut deep, closely spaced grooves into the ground. In absence of the hopper, broacasting seed after the Verticut then a light topdressing works.

If the issue to be corrected is hard soil, I get more out of correcting soil chemistry and adding soluble organic matter. What is soluble organic matter? Sprayable Humic and Fulvic acid materials. Soil chemistry needs to be corrected as well. By that, I am referring to Calcium, Magnesium, Sodium, and pH. Soil that has the chemistry issues corrected and then treated with Humic and Fulvic normally becomes rather porous.

N=1. I remember cores aerating a 1/2 acre Zoysia lawn. Job took hours. Grass and soil did not improve enough to justify the labor. Especially not when correcting soil chemistry and adding soluble OM drastically improved the situation.


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## kevreh (Apr 3, 2018)

Good info, thanks for posting that. I don't want to get too off track on this thread, but you mentioned humic and fulvics. Are they all the same whether using dry (and mixing yourself) or buying them in liquid form from the likes of n-ext (like their rgs mix)?

I'm going to start using the n-ext products this week, your post and others above remind me to do a rod or screwdriver test before and after.


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## Greendoc (Mar 24, 2018)

N-Ext is a predissolved Humic and Fulvic mix. Only reason why I do not use RGS is for what shipping costs to Honolulu. I like Andersons K-Mate SG. That one is a soluble powder where one bag covers several acres.


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## ryeguy (Sep 28, 2017)

Why buy rgs products instead of buying kelp powder and making it yourself? Isn't it the same, but much much cheaper?


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## GrassDaddy (Mar 21, 2017)

So the process to have it liquid to mix or powder to mix is different. Theoretically speaking the liquid should be better. However I don't know if there are actual trials to show that effect. But it's similar like food products that get processed, you lose nutrients during the process.


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## Colonel K0rn (Jul 4, 2017)

ryeguy said:


> Why buy rgs products instead of buying kelp powder and making it yourself? Isn't it the same, but much much cheaper?


FWIW, Pete Denny of GCI Turf just released a video today where he explains that the humic acid that you're buying is going to be reconstituted when you add water to spray it, as opposed to the RGS product where it's ready to go. RGS is Leonardite (where humic acid comes from) that has been reacted and mixed, with no loss of efficacy, along with kelp and fulvic acid. Pete used to mix the humate product that he applied to his own yard, as well as customers yards from different sources and vendors; to wit he has purchased a lot of equipment to mix it and store the separate ingredients to mix his own spray treatments. GCF is not a new business, as they've been operating out of FL for quite a few years. It is advantageous as a business owner to find a company that is making a product for you that's ready to go, and costs less than what you were mixing on your own.

To give a bad analogy, would you rather have frozen orange juice concentrate, where you have to mix the frozen contents of a container, or would you buy the OJ from the refrigerated section? Sure, you can buy your own oranges, and squeeze them yourself, but in the end, which is going to give you a better-tasting orange juice? How about Tang? 

P.S. If y'all aren't subscribed to Pete's channel, you should. He gives away a bio-stimulant pack and a 50# bag of his TTTF seed every 1K subscribers. He's good people, and passes along a lot knowledge and experience in his videos.


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## ryeguy (Sep 28, 2017)

Yes, I watched that video. I might have missed it (twice), but I didn't hear anything in there actually comparing the efficacy of powdered vs liquid, even at the timestamp you linked. He just mentioned he's used both.

Both of you have mentioned that the liquid version is more efficacious, but couldn't that be countered by just using more of the powdered form? Also, do you have links that support this? I can't find any when googling.


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## LawnNerd (Sep 2, 2017)

GrassDaddy said:


> My two experiences.. we core aerated the church and two weeks later the holes had filled in. In my backyard my screwdriver couldn't go down an inch but then using soap and yucca it could go down a foot.
> 
> So I'm a fan of core aeration when applying something like seed but otherwise I see it as a temporary solution. Golf courses and Fenway etc will core aerate and then topdress with sand but residential we never see that recommended.


This was my experience as well. I don't think core aerating should be black and white like how it's portrayed at ATY, and there certainly is no reason why one couldn't do both, except for budget.

I aereted for 2 years, twice each year. I saw no difference, and like GrassDaddy mentioned above, the plugs would be dissolved and holes filled within a week or two. I saw no overall increase in my turf quality. My biggest issue, and reasoning to aerate, was that the soil was so tightly compacted (decades of neglect) that water would literally bead up and run right off. It had almost no percolation ability, so it was always bone dry. Last year in the spring i switched to soap and yucca and applied monthly and i can tell a massive difference. This Spring i'll be adding in humic acid to my regimen, and i'm hoping this will even better increase it's percolation and water retention.

Another thing was after having my soil tested, I was able to learn that I also had a 2:1 - 3:1 Calcium to Magnesium ratio. This ratio will lead to really tightly packed soil. With a soil PH of 5(ish)i was able to throw down straight calcium to correct this ratio and PH. I believe this is also playing into why my soil is "loosening up" while not aerating.

It wouldn't have mattered how many times I aerated or soaped the soil, i would have always been playing with one hand tied behind my back. So, get your soil tested and learn if you have any handicaps. Like Professor Pete says "Get Your Dirt Right!"


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## kevreh (Apr 3, 2018)

Good observations on the benefits of liquid vs mechanical aeration.


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## Greendoc (Mar 24, 2018)

There are skeptics of correcting Ca and ph. I have seen them in the industry. Most of them are heavily invested in mechanical aeration and the need to dethatch. On dethatching and this is relevant to aeration/maintaining porous soils, tight, non porous soils will tend to make the grass keep its roots closer to the surface. What I call thatch consists of roots and rhizomes forming a mat on the surface and getting thicker by the year. Whatever grass clippings accumulating are the result of those clippings never touching soil and building up on top of that mat. The people invested in constant mechanical aeration are not looking past the physical work. Which is wasted work. Only time I believe in core aeration is if it is done to the point that 30-50% of the existing dirt is going to get removed while the grass is still in place and replaced with sand.

"Get Your Dirt Right" indeed. Not getting your dirt right sets you up for a lot of work. I do not know about you, but I call having to walk a dethatcher back and forth over a lawn, then bag up the mess work. Getting yanked from one end of the lawn to the next behind an aerator is also work. If I have to do something like that every year and not see a decrease in the need to do that, I call that wasted work.


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## Green (Dec 24, 2017)

ryeguy said:


> Both of you have mentioned that the liquid version is more efficacious, but couldn't that be countered by just using more of the powdered form? Also, do you have links that support this? I can't find any when googling.


Not sure if there is any research on that yet. But, I doubt there would be much difference in the end result depending on what you used if the key ingredients were the same, as long the products were "fresh" (bioavailable and bioactive).


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## Ridgerunner (May 16, 2017)

What does HA, FA, Yucca, pH or soap have to do with mechanical core aeration?


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## Green (Dec 24, 2017)

Ridgerunner said:


> What does HA, FA, Yucca, pH or soap have to do with mechanical core aeration?


It's something two people (not from here), who really know a lot about soil, have tended to steer people toward for the past few years.

And now everyone else (the youtube video watching crowd) is jumping on that bandwagon, too, it seems, as of more recently.

Coincidence?? I don't think so. All these people's results speak for themselves...it seems to work.


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## Pete1313 (May 3, 2017)

Greendoc said:


> Only time I believe in core aeration is if it is done to the point that 30-50% of the existing dirt is going to get removed while the grass is still in place and replaced with sand.


Are you suggesting aerating to an affected surface area of 30-50% at one time? Removing cores and then adding sand?


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## Ridgerunner (May 16, 2017)

> It's something two people (not from here), who really know a lot about soil, have tended to steer people toward for the past few years.


Extraterrestrials? Thetans?

Compaction. Mechanical means is the only method for reducing compaction. That is, reduce soil bulk density. Unless you can cite a study to the contrary.
All of the other methods (collectively "liquid aeration") treat the "symptoms", not the "disease." Not that each of the products may not have a desirable effect on turf (or soil), but they don't eliminate compaction.


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## Green (Dec 24, 2017)

Ridgerunner said:


> Compaction. Mechanical means is the only method for reducing compaction. That is, reduce soil bulk density. Unless you can cite a study to the contrary.
> All of the other methods (collectively "liquid aeration") treat the "symptoms", not the "disease." Not that each of the products may not have a desirable effect on turf (or soil), but they don't eliminate compaction.


I've heard it stated that there are two different types of soil "compaction"...mechanical, which you're referring to, and electrochemical (but maybe it's called something else...not sure what the actual term was), which is totally different. But both tend to result in difficulty pushing a compaction probe into the soil, for different reasons. I don't know how much of this is actually true, but it's what I've heard.

in any case, the liquid aeration products, organic matter, biostimulants, etc., I believe are intended to actually improve the electrochemical (or whatever it's called) compaction type.

Also, earthworms can help reduce mechanical compaction to some extent.

But if you've physically compacted the soil, I would think you're right, that it has to be physically uncompacted...at least that makes sense to me.


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## Greendoc (Mar 24, 2018)

Pete1313 said:


> Greendoc said:
> 
> 
> > Only time I believe in core aeration is if it is done to the point that 30-50% of the existing dirt is going to get removed while the grass is still in place and replaced with sand.
> ...


Correct. Understand that I am talking about doing this to Bermuda or Zoysia that is growing on horrible soil. If you have to do this to Fescue or KBG, this might have to be done in the Fall when you can put down seed. If I ever have to deal with an area with horrible soil before a single square foot of sod goes down, the soil gets stripped out and replaced with a sand and organic matter mix. I am dealing with grass that is already high maintenance. Doing a half @ss job during the preparation just makes it harder.


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## Greendoc (Mar 24, 2018)

Green said:


> Ridgerunner said:
> 
> 
> > Compaction. Mechanical means is the only method for reducing compaction. That is, reduce soil bulk density. Unless you can cite a study to the contrary.
> ...


Correct, correct, and Correct. I also have observed that soils with bad electrochemical properties will compact with very minimal physical force. Walking on it once a week is enough to do it. Use that kind of soil for a sports field, forget it. I believe that mechanical procedures are treating symptoms of bad electrochemical properties. For a soil to get that bad, I want to know about the 5 ton roller or else the gorilla going around the yard with the "jumping jack" hand held compactor. If the soil got that compacted via light foot traffic, that is a chemical problem to me. I know what happens to soil that has taken up too much Sodium and Magnesium. Easy to happen when I can see the ocean, smell the ocean, and hit salt water if I dig down. Mechanically uncompacting such soils is wasted work. Getting the Sodium and Magnesium displaced as well as making the soil aggregate into particles less likely to compact is a more worthy exercise in that case.


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## Colonel K0rn (Jul 4, 2017)

Greendoc said:


> Green said:
> 
> 
> > Ridgerunner said:
> ...


And this is exactly the reason that I'm following the lead of someone who took red North Carolina clay 6 years ago to where they can easily push a 3' probe into his soil. I'm not sure if you've seen red GA clay, but that stuff is  to dig through. I don't have it as bad down here on the coastline, but I do have problems similar to what you're mentioning with the Na and Mg displacement. I've got all sorts of maladies going on with my soil, and I'm doing what I can to #getmydirtright. If someone has a product ready-made that I can apply to improve the conditions for the soil over a long term, with no ill effects, I'll spend my money on it. I have neither the time or inclination to invest time into becoming a soil scientist, but I'll learn enough to be able to ask those who know more about it the right questions to help me achieve a desired result.


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## Greendoc (Mar 24, 2018)

I will not spend time or money on doing something so grueling that I am bed bound for the next two days with no long term benefits to show for it either. If I can run it through my boom or hose end gun, and make a positive change that is how I am doing it. Even if the benefit is small and incremental, that is ok with me. Because being bed bound for two days for minimal gain, is not sustainable to me.

Hawaii red volcanic clay must be the tropical version of what you have in Georgia and the Carolinas. When it is dry, you need a jackhammer to get into it. If it is wet, it turns into grease. A lot of that has to do with Sodium and Magnesium. Till in incompletely decomposed organic matter(compost), you just made adobe brick my friend. Treating soil to correct pH and excessive Sodium/Magnesium along with soluble organic matter has done more than getting dragged around by a 300 lb machine all day. I almost forgot. Mixing sand into this bad soil makes concrete unless the sand content is 50% or more of the soil composition. That is why I am suggesting that people with this kind of hard clay aerate such that they are taking away up to 50% of what is there and putting sand back into the holes. A hole punched every 4 square inches is not going to do it as in a TG or "landscaper" aeration is not going to do it.


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## Pete1313 (May 3, 2017)

Greendoc said:


> Pete1313 said:
> 
> 
> > Greendoc said:
> ...


The reason i ask is because i believe 30-50% like you mentioned and then amending with sand could be a good goal over time (3-4 separate attempts). But would be too much at once. What machine are you using that will allow you to aerate an existing turf regardless of species to 50% affected surface area without doing so many passes that it destroys the area?

For reference, a John Deere Aercore 800 greens type aerator if setup with large 3/4" diameter tines will only aerate to 11.04% affected surface area in a single pass with 2" x 2" spacing. You would need to go over the area 4x with that machine to get 44.16% affected surface area. 44.16% Would be 144 holes with that 3/4" tine per sq ft. Or the equivalent to 1" x 1" tine spacing. It would also take 4 cu yds of sand per 1000 sq ft to fill all those holes if you aerated to a depth of 3"

I aerated to just over 16% affected surface area on my renovation, although I didn't amend with sand as i dragged the cores back in to smooth it out. I feel if I did that X3 I might as well have tilled the soil even if I removed the cores.

Before









16% aeration









After dragging


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## Greendoc (Mar 24, 2018)

That is why I mentioned seeding for cool season grasses. I am in total agreement that extreme aeration like 4 passes would be as good as tilling up cool season grasses. Bermuda or Zoysia is not destroyed by severe mechanical procedures. You can take off everything scalp those grasses until you see dirt, even run a sod cutter and take off the first 1/2 inch of roots. Those grasses will still grow back. God help you if you ever till under Bermuda or Zoysia without spraying some grass killers above and beyond RoundUp expecting to get rid of it because that will not kill it. am talking about instances where corners were cut, things were done wrong, and one is at the point where things need to be fixed no more  around by doing a little of it over 5 years because the homeowner is pizzed and wants it fixed right now for good.

Your calculations are totally correct. I would never do more than say 20% replacement in one year if I were doing it on Fescue or KBG and I was not seeding after. Thankfully, in most cases, the soil is never that bad where those grasses are normally grown. The fact that your cores broke up and could be used as topdressing says it all. If I ever core aerated the typical lawn in my location without picking up and throwing away every single plug, I would have plugs of mud that would never go away. They would form greasy smears that will not break down. It is extremely rare that I see soils that are mostly sand. If there was sand, a jackwagon "landscaper" freaked out because he saw sand and pasted on 6" of volcanic clay. To fix that mistake, I end up applying enough sand to replace 50% or more of that clay. I never get called to deal with a lawn that is on sand. Such a lawn needs very low inputs compared to one where there is clay involved. Routine mowing and irrigation is all that is required. Because there is no clay confounding the growing conditions, the grass also gets by on comparatively low nutrient inputs as well. The roots go deep and look for water and nutrients. On clay, they tend to stay at the surface.

It is far easier to deal with cool season grasses. At worst, dumpster fires can be re graded and re seeded. Turf dies. Re seed. Warm season grass is different unless one is willing to use seeded varieties of Bermuda or Zoysia that are not as finely textured as their hybridized "rich part of the family" cultivars. When dealing with something that is only sold as sod, scraping something flat and re doing the soil underneath is not taken lightly. The saving grace is that thanks to deep underground rhizomes, dumpster fires in warm season grass may be buried in a lot of sand or scalped off like pushing the reset button on my tablet.


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## Green (Dec 24, 2017)

I like the turn this thread has taken. @Greendoc and @Colonel K0rn , we have pockets of some orange sand up here in my area of the Northeast. I'm not sure if that's related to the NC red clay at all. It gets hard enough that you can't really push through it with a soil probe, but it's not clay, as the particles are large.

Also, Pete getting a probe 3 inches *feet* into the soil in every spot he tried was impressive, and it sold me on chemical aeration/biostimulants. This year, I am going to make my own product according to the recipes of the guys from that other website we've already mentioned. In the past, I took the shortcut of using shampoo (which wasn't too effective) or buying a granular wetting agent (which was way too expensive). That said, I will never get a probe down 3 feet, as we are full of rocks here.


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## Ridgerunner (May 16, 2017)

Although mechanical core aeration can and is used for other purposes than to alleviate soil compaction (to affect a greater soil profile/depth with amendments like nutrients/fertilizers, sulfur, lime, peat moss, sand, create short lived "dry wells" for drainage, etc.) its primary, unparalleled function is to reduce soil compaction.
Compaction is a determination based on the measurement of Bulk Density. _From my thread in the FAQ section:_


> Bulk Densities (compaction values that can impede root growth) by soil classification. Needs to be determined in the field. In general, any bulk density in excess of 1.6 can be expected to restrict root growth.
> 
> Sands = >1.75
> Silt (and Loams) = >1.60
> Clay = >1.4


Values that exceed those listed above DETRIMENTALLY affect root growth, water movement, gas exchange etc. resulting in poor turf performance. That is, the empty spaces between soil particles has been reduced to a point where soil particles cannot be dislodged or moved aside to allow root penetration, water can not easily percolate down or effectively be pulled up by capillary function, and CO2 and oxygen cannot readily move into and out of the soil. The soil is compacted.
Penn State University used to have a link to an article that stated that studies had found that a one time application of a force of 15#/sq inch (equal to the amount of force exerted by a 160# person walking) could be sufficient to compact soil to 70+% of its maximum compaction potential. 
Some "electrical/chemical" soil conditions can exacerbate compaction or the potential for compaction. High Sodium levels make for weak soil aggregates and conditions where soil particles easily disperse thereby reducing soil voids. Although these types of soils do occur in the upper plains of the U.S., they are not common in other regions. Sodium levels do not generally reach detrimental levels until they exceed 15% of Base Saturation resulting in crusting, impermeable layers and plugging of spaces between larger soil particles. High Magnesium levels have a similar effect that results in soil particle dispersion, creating tight clay layers and blocking soil spaces. However, the threshold for Magnesium detrimental levels is also greater than 15% of Base Saturation and also soil testing levels greater than 300 ppm/600 lbs per acre. Not very common. 
Mechanical intervention (core aeration), is the only known expedient method for reducing soil compaction. It is short-term, but during that term, while the soil's bulk density is reduced and pore spaces are more abundant, water, nutrients, amendments, and roots have a greater likelihood of penetrating a large portion of the soil profile. That is an opportunity for improving the effectiveness of applications of Sodium and Magnesium reducing products, and a window for improved root growth, OM dispersion, a more conducive environment for soil life, and soil aggregation. All of which will reduce the incidence of future compaction.
On the other hand, maybe your soil isn't so drastically compacted (everything is a continuum or at least, seldom a cliff) that the application of a sufactant, will be enough of a "hand-up" for the turf to overcome the impediment. Maybe.


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