# Aeration, sanding, and PGR questions



## FATC1TY (Jul 12, 2017)

Probably a bit more to bite off so quickly, so wanted to get some thoughts on my plans here.

Grass is greening up well, had been scalped back in late feb I believe, ronstar g applied for PreM and I've done very little other than a few random pulls of small weeds I see near edging and the street. Back yard is slower to green with some troubled areas that I hope start to show more green and less dirt/dormant grass.

I need to aerate with a core aerator this year. Didn't do it last yr and I have extremely compact, rock filled clay soil. I plan to aerate and then top dress the yard at the same time. Planned to put down some fert after aeration, add sand to top dress and spot level some areas and let it go.

Sounds okay, right?

Now... let's add PGR to the mix.

Having never used it, but wanting it more for the benefit of deeper roots, better growth laterally, shorter stolens, etc, rather than the mowing decrease. Would it be advisable to wait until the repair from the aeration and the top dressing before applying the PGR or would one see benefit in helping repair and cover the injury with the PGR?

My gut says to do the work as planned and apply the PGR after the grass is 75% repaired and then carry on with normal routine.

I'm leaving mid May for vacation and while I know the yard won't be full bore crazy growing, it would be nice to be able to have PGR down, and not really miss a mow during vacation.

Thoughts ?? PGR seems counter intuitive if it's not going like crazy from the onset, and would delay any grow in using it early...?


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## Suaverc118 (Jul 28, 2017)

I want to know about this as well. Following thread.


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## Kballen11 (Mar 26, 2018)

Suaverc118 said:


> I want to know about this as well. Following thread.


+1


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## viva_oldtrafford (Apr 4, 2018)

Post aerification is the only time I want the grass burning through carbs like crazy. When we aerify greens / tees / fairways, it's always a minimum of 2 weeks before we get back on the primo bandwagon.


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## kur1j (Jul 2, 2017)

viva_oldtrafford said:


> Post aerification is the only time I want the grass burning through carbs like crazy. When we aerify greens / tees / fairways, it's always a minimum of 2 weeks before we get back on the primo bandwagon.


@viva_oldtrafford

Was planning on scalping, dethatching, renting aerator and then leveling, does that sound reasonable? It's hard for me to plan around leveling and aeration as i'll have to rent and get sand delivered but is it an absolute must to aerate before you level? How soon after aeration should I level?


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## Greendoc (Mar 24, 2018)

For the work that needs to be done, aeration yields a very low return on investment in rocks and clay. Home lawns are on rocks and clay, I get more mileage out of a heavy sand capping program. Aeration becomes worth it if you are going to pull out cores very deep and spaced extremely close together. I am thinking 4-8 passes over the same area and more than an inch deep. The cores pulled also need to be collected and disposed of. Then sand is to be used to fill the holes. For such an intensive and intrusive process, I would not want grass on growth regulation. It is not fertilizer, it is the very opposite. Yes, a PGR can redirect more growth towards roots and stems, however that is on grass that has not been subjected to stresses or injury of any kind. Dethatching and aeration count as injury. Having to grow through a sand layer is a stress.


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## kur1j (Jul 2, 2017)

@Greendoc

No to thread jack, but what is "sand capping?" i'm planning renting a toro stand on aeration machine. It will pull 4" plugs out of the ground about 8" apart with one to two passes. Obviously could do more passes. Would that be what you would consider worthwhile? Would you consider dethatching worthwhile?


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## Greendoc (Mar 24, 2018)

I would go ahead with the deep, intensive aeration followed by sanding. Next question is: how much thatch have you got and what is that thatch composed of? If the "thatch" is mostly what happens when grass is not mowed low enough, I would simply scalp and I mean really scalp. My idea of a scalp is taking grass down to 0.1". 0.5" is maintenance height for me. If it is a spongy layer of dead stems and roots such that the green part of the grass is separated from the soil be over 1/2" then maybe.

I have a confession. I have not dethatched a lawn in decades. Everything I have done involved scalping down to 0.1" or as low as I could go without hitting dirt or rocks. Reason why is that most dethatching machines designed for home lawns would choke on Zoysia in Hawaii. I would need something equipped with carbide blades on a fixed shaft. That is not commonly marketed towards lawn and landscape use.


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## Greendoc (Mar 24, 2018)

kur1j said:


> @Greendoc
> 
> No to thread jack, but what is "sand capping?" i'm planning renting a toro stand on aeration machine. It will pull 4" plugs out of the ground about 8" apart with one to two passes. Obviously could do more passes. Would that be what you would consider worthwhile? Would you consider dethatching worthwhile?


Sand capping is putting on a layer of sand over an inch thick such that the grass develops a new root system in that sand layer. http://www.golfcourseindustry.com/article/gci1213-sand-capping-fairways/ That article talks about covering over bad soil and establishing the Bermuda in the sand. My reason for doing it is to rehabilitate lawns growing on clay too poorly drained and contaminated with salt to fix any other way. The golf courses in Southeast Asia have to do this as well because they are growing grass on soils with the texture of grease. Not much different from Hawaii. Our soils are the texture of grease when they are wet.


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## kur1j (Jul 2, 2017)

@Greendoc

Thanks. I'll dig up a section and take a picture of the thatch. I feel it needs it but I could be wrong.

I highly doubt i could get down down to .1" too many small undulations and stuff in the yard (hence wanting to level). I don't think my yard is terribly out of shape for leveling but it's certainly not .1" smooth. Im thinking without leveling i'll be around .3-.5" for scalp. I want to maintain around .75 or so as I don't want to be be just pissing nitrogen at it, cutting it slightly higher will reduce my inputs to some degree and reduce chance of infections from my understanding.


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## Greendoc (Mar 24, 2018)

Small undulations, then how about we meet halfway? I scalp those at 0.2, which gets it almost to dirt. On the height of cut: in wet or humid conditions, I find that a high height of cut contributes to more Pythium, Leaf Spot, and Brown Patch. However, starvation conditions combined with a low height of cut contributes to more Dollar Spot and Bermuda Decline. When I say starvation, I mean those golf greens being maintained on less than 0.5 lb of N per month. Remember that they are being mowed at 0.1" and the clippings being collected. I mow at 0.2-0.3 on Bermuda, cut in my clippings, and apply 0.5 lb of N per month. No disease. I have some golf friends, they hate the starvation programs. Yes, the green is faster, but it is prone to Dollar Spot and worse.


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## FATC1TY (Jul 12, 2017)

I figured to so many passes with aeration. Neighbors had their done by a service. One pass and can't even see any cores myself. What a waste!

Plan to really get into mine and top dress it heavy. Will toss in fertilizer on it and add sand and try t kill a couple birds with one stone.

Figure I can do this before I leave in 3-4 werks. The sand sound slow growth I think.

Should figure late May early April to be where I want and getting it tuned in and adding PGR to the regimen.


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## FATC1TY (Jul 12, 2017)

Estimated yards of sand for 4000sq ft worth of grass for a hearty top dress and half a$$ level?

Thinking about getting this done sooner than later while I have the free time.


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## Greendoc (Mar 24, 2018)

5 yards or else 7 tons.


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## Colonel K0rn (Jul 4, 2017)

Greendoc said:


> 5 yards or else 7 tons.


Sounds like sand capping might be right up my alley, since I had a high salt level soil back in June. I should do another soil test to find out where I'm at. :| Is that amount that would be needed to sand cap 4K? What would you estimate to sand cap 4.7K, because that's what I'm looking at for the front of my property.


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## Greendoc (Mar 24, 2018)

4.700 would be more like 8 tons. You will also have to do this 2-3 times more after the initial application.


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## kur1j (Jul 2, 2017)

@Greendoc

I plan on cutting as low as the yard will let me. Maybe I can get it to .1"? I don't know. It just seems unlikely to me from the way it looks. I'm certain there is more than .1" of movement in dips/valleys/cups. A few examples would be, 1) there are places where the sod layers didn't butt the sod up close to each other correctly so it's a 3/4" quick drop 3-6 inches wide. Before I got the reel, with the rotary I would have to keep the wheels on the high points otherwise it would drop into it and dig dirt. I know with the greens mower it has the drum so it will roll over that easier/better but i almost high point in some areas at .5 so i'm sure I will at .1" 2) There are places where the greens mower is bouncing all over. Mower is shaking and moving because of the roughness of the lawn.

I'll give it a shot and maybe I'm wrong, but just very speculative I'll be able to get that low.

My goal is to be able to drive the greens mower where it's not moving, bouncing digging into stuff or anything. Just a smooth, engage of reel and walk.


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## SCGrassMan (Dec 17, 2017)

I'm in a similar boat with the clay soil, although in my yard its a good mix of sand and topsoil underneath but with areas where its more clay and thus poor drainage.

I plan on sand capping over the next couple of years, but my question is how to avoid raising the height of the yard by however much sand I put on, deep core aeration with tons of passes, and then removing the plugs from the yard?


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## Greendoc (Mar 24, 2018)

That would be the way. Severe aeration that removes almost as much material as being put down. By doing that, you are also diluting the existing clay with sand. My situation is normally that the existing soil has undergone shrinkage and settling. Convention in Hawaii is to put lawns on a soil composed of up to 60% undecomposed organic matter and the rest clay. That soil is graded so the initial install is level, so it is by no means of uniform depth throughout a property, I will let you figure out what happens when that organic matter decides to decompose. Or the clay shrinks or settles from heavy rain. It takes 2-3 inches of sand to get such a lawn level enough to mow. Without sand, the sinkholes and divots are so bad, they are often "mowed" with three people walking side by side with string trimmers.


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## SCGrassMan (Dec 17, 2017)

Greendoc said:


> That would be the way. Severe aeration that removes almost as much material as being put down. By doing that, you are also diluting the existing clay with sand. My situation is normally that the existing soil has undergone shrinkage and settling. Convention in Hawaii is to put lawns on a soil composed of up to 60% undecomposed organic matter and the rest clay. That soil is graded so the initial install is level, so it is by no means of uniform depth throughout a property, I will let you figure out what happens when that organic matter decides to decompose. Or the clay shrinks or settles from heavy rain. It takes 2-3 inches of sand to get such a lawn level enough to mow. Without sand, the sinkholes and divots are so bad, they are often "mowed" with three people walking side by side with string trimmers.


 :crazy: :crazy: :crazy:

String trimmer line of people. Good Lord.


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## Greendoc (Mar 24, 2018)

My greensmower actually does a good job on most String trimmer lawns. Most lawn crews have McLanes and Tru-Cuts. No good on anything less than a countertop flat lawn. Front and rear full width rollers make the mower more tolerant of ground deviations.


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## SCGrassMan (Dec 17, 2017)

Greendoc said:


> My greensmower actually does a good job on most String trimmer lawns. Most lawn crews have McLanes and Tru-Cuts. No good on anything less than a countertop flat lawn. Front and rear full width rollers make the mower more tolerant of ground deviations.


It's alarming that there is such a thing as a "string trimmer lawn".


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## Greendoc (Mar 24, 2018)

Its not by accident that I am the only TLF member from Hawaii. People in business think there is nothing wrong with using a string trimmer on huge areas every week 12 months out of the year. Disgusting is what it is.


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## FATC1TY (Jul 12, 2017)

So to un hijack and clear up, does anyone have some good guidelines to when to resume a PGR application or start one, after aeration or any aggressive treatment such as heavy sanding/top dressing?


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## Greendoc (Mar 24, 2018)

I would wait until the grass is growing enough to need more than a once a week mowing as a guide. When I do the sand capping operation, it is normally 2-3 weeks before the lawn is ready to mow again and if I am not putting on more, it starts to grow normally 2 weeks after that. This is for a heavy topdressing above and beyond the normal 1/4-1/2" . I am at 1" and even more than that if I am filling in holes from shrinkage or settling.


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## SGrabs33 (Feb 13, 2017)

Greendoc said:


> I would wait until the grass is growing enough to need more than a once a week mowing as a guide. When I do the sand capping operation, it is normally 2-3 weeks before the lawn is ready to mow again and if I am not putting on more, it starts to grow normally 2 weeks after that. This is for a heavy topdressing above and beyond the normal 1/4-1/2" . I am at 1" and even more than that if I am filling in holes from shrinkage or settling.


How do you keep the sand in place when you are sandcapping? We get so many storms in the spring that I would worry about it all washing away.


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## Greendoc (Mar 24, 2018)

You do it when you have a little more control over water. Right now would be a bad time. I would not sand a lawn at all right now. Going on 3 months with almost constant cloud cover and just about weekly flash flooding. Besides, if there is too much cloud cover, there is not enough sun for grass to grow.


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