[Ian Larson]

Sand on top of gravel will not fail IF SIZED PROPERLY. If the greens you are referring to Tom consisted of mostly fine gravel there is no way that it can come even close to considering itself a USGA spec green.

If the super had a growing medium that essentially consisted of larger particle sizes, too large to topdress with....those greens were built way out of USGA spec. Those greens and the USGA shouldn't even be used in the same sentence. If a USGA agronomist advised on this then yeah, they're to blame. But Im sure they didn't because the larger particle sizes in the top end are only a small percentage of the overall mix and nobody from the USGA would go outside of the above specifications. Certainly not to the point where the particles were so large that by topdressing with a smaller size created a perched water table in the top 2".

Tim, I disagree that the larger particles on the top end are a flaw of the USGA spec. As I said above the overall percentage of larger particles in the mix is small and anything coming close to fine gravel is not even recommended. Any fine gravel in the mix will throw off the porosity established from the relationship of the percentages of all the other sizes.

Bottom line....if a super has a growing medium that when choosing a topdressing sand, the sand is too big to do it because of mowing. IT IS NOT A USGA GREEN.It is a cheaper knock off version. If my girlfriend buys a Louis Vitton handbag in Chinatown and it breaks, is Louis Vitton responsible for it? Hell no. And the USGA shouldn't be associated with greens not built to their specifications.


A properly built USGA spec green has no problem being topdressed with a #30 or #40 mesh topdressing sand. If you try to topdress with masonry sand because its cheaper, your going to be making the mechanic and your bed knife budget very angry.



Again, another set of greens failed ONLY because someone thought they could save money in construction or renovation. They went with a larger particle size because it was cheaper. And now look what is happening....the things are being rebuilt. All that time and money spent before was for nothing and now its going to cost even more.

Just like Brad Anderson said earlier, I dont know why the USGA gets the rep it does. Its incidences like this that make me wonder when someone goes the cheap route, greens go bad....and they have the "USGA" tag on them. When they're not.     

[Tom_Doak]

Ian:

I will agree to the extent that I don't believe the materials used in the previous construction would have passed USGA specs.  The problem is that no one at the club checked them independently, the architect didn't check them either, and the contractor just installed what he wanted to.  There's a bit more to it than I am explaining, but I don't want to get into the dirty laundry any further, we can all smell it.

The problem is that these greens were, in fact, sold to the club as USGA greens, constructed in multiple layers, etc.  The members didn't know how the materials could destroy the whole process, clearly, or they should not have had this problem.  I was not intending to use this as an example of how properly-constructed USGA greens fail.  Properly-tested USGA greens should NOT fail for soil hydrology reasons.

But push-up greens built properly with proper materials specified by a reputable agronomist shouldn't fail, either.  The USGA specs make their method sound bulletproof, but in fact all methods are subject to the same root causes of failure ... poor materials used by someone cutting corners, or poor agronomy by the guy growing in and maintaining them.  Or, I guess, poor design if they are too steep for fast green speeds or too flat to drain properly.

One problem I do think USGA greens have caused is an idea by some that you don't need good surface drainage on the greens because they are built out of sand.  In my estimation that has caused agronomic problems on some modern greens that are designed with 1% or less surface drainage.  If you rely on the mix to soak up runoff or flood water, you've got water standing on the greens for too long, and that is a problem when hot and humid conditions prevail.

[Tim Nugent]

Ian, my point wasn't in the larger end of the acceptable gradation was problematic in the construction mix, but rather what can pass for an acceptable rootzone mix for construction may not be suitable for topdressing  - as you agreed, it can play hell with reels and blades.  The thing that's tough as a specificer is just pasteing in the table you supplied can satisfy the requirement for a USGA Green while still not being a suitable topdressing material.  Hence, there will be a statified layering in the green.  I've seen some pretty coarse USGA mixes, I've also seen them on the fine end of the scale too.  I've even seen where the supply of one "acceptable " sand ran out after a number of greens were constructed and the contractors found another "acceptable" sand but the supers ended up with greens with different characteristics.

Tom, don't forget to add Ice to your list of poor surface drainage woes. Water typically needs 2% to drain.  In winter in northern climates, sand greens will freeze solid and become impervious.  When snow melts and refreezes at night (and then for a protracted period), grass can killed.  Woe is the super who has to explain why he is sodding chunks of greens come springtime.

Gotta go snowblow the drive.

[Ian Larson]

Tom,

I completely agree that push-up greens shouldn't fail as well. FWIW I don't think USGA is the one and only way. If the material on site is suitable then push-up should be one of the first options. Because I agree with you, that if the money doesn't need to be spent...it shouldn't be spent.

If I were on-site and native push-ups were being considered my personal criteria for signing off on that would be..

1. Is there enough material to give me 10-12 inches of consistent rootzone for the total volume of greens. If there isn't enough material to give me 12" by...say 3 acres (estimate) I wouldn't even take the next step of getting it tested. The worst thing is having a hodge-podge of greens with different soils at different depths. Can it be done hodge-podge? yeah but it completely sucks when managing it.

2. Get the material tested by an accredited lab. Maybe even 2 or 3 labs to get another opinion in results. And I wouldn't be sending in zip lock baggies full of soil that were scooped out of the ground with a shovel. I would be cutting up 4" pvc pipes atleast 12" long. Pounding them into the soil as it naturally lays in a naturally compacted state to send in 12" soil profiles from at least 3 spots in the green site to see if its even consistent. So not only would I be getting the particle size distribution analysis I would be testing the natural hydraulic conductivity of the soil in its natural state. 

If it not within range or its not percolating at atleast 6 inches/ hr then I'm completely against the push-up idea. That is when it is worth spending the money and doing right from the beginning.


With the surface drainage issue....I personally have worked for guys that paid attention to the surface drainage percentages doing USGA greens. The surface was always the primary line of attack when it came to draining a green. But they are designed to take on water and evacuate excess. Even on a 1% slope the profile will take in the water and allow it to move downwards away from the rootzone. Its less catostrophic if there is a big rain event and the soil profile gets saturated. It drains by the next day. In a soil push-up...it can ruin the whole week with mowing and playability.



BTW Tom.....with push-up greens do you or have you ever considered using drain tile in the push-up? I know that with renovating some old push-up greens I've found the old clay tiles that the ODG's would use in building their greens. I think drain tiles serve a great function in the soil profile by creating the pocket of low pressure, which increases the hydraulics and gives the water a point of least resistance to travel towards. In the pipe and gone....

[Ian Larson]

Tim,

You are correct, a USGA greens mix can very well be a great choice for for the construction but not so great for the topdressing. Personally....I choose to never use a USGA mix for topdressing. I think its poor greens management to topdress a USGA green, that already has a percentage of organic added to it homogeneously, with more organic. The whole purpose for topdressing is to dilute the accumulating organic material in the thatch, why continually add more organic that will collect up in the surface. Organic is supposed to be homogeneously dispersed throughout the soil profile...not topdressed on the canopy where it can build up within a small area. That is a definite way to create a perched water table over time.

A USGA on the coarser end or one that is on the finer end, it doesn't matter. A #30 or #40 mesh sand is topdressing sand that is a single size with no organic. Topdressing should only be a screened aggregrate that is one size. And over the years I've never seen any problems with layering when a clean / screened 30 or 40 mesh was used. It spreads in nicely to the canopy and it dilutes the organic. Melts into the soil profile.

As far as the project you saw that had acceptable sand run out.....Thats poor project management 101. If greens are being constructed or renovated for USGA spec the first thing that needs to happen is someone physically going to the plant and reserving their piles for their project. And while they are there they are collecting their own soil samples from inside the piles to send to the labs. I know shit happens sometimes, but running out of material in mid project is bad project management....from the contractor and the supers end. The super should have been the leading force with material, how much, is it all tested and getting it on-site for the contractor.


With USGA greens freezing....Ive seen soil greens freeze just as bad. They are more prone to holding more water with less options for draining it. I know Sub-Air isn't regarded very well on here but with a simple slice valve installed on every main line drain in a USGA and a portable Sub-Air unit....USGA greens can be kept bone dry throughout the winter with only air in the macro pores instead of water. They can also be pumped full of warm air to oxygenate the root zone and maintain higher soil temps throughout the winter. As soon as spring breaks and the snow melts it takes 1 day to go around and pump out all the water from snow out of the soil. With a push-up your at the mercy of mother nature and the existing perc rate of the soil....


....and don't get lost out in the snow drifts. This is when I love living in Southern California!

[Tom_Doak]

Ian:

We have put drain tile underneath the push-up greens, on a couple of occasions early in my career.  We thought that if there was some problem with the green down the road, requiring additional drainage, it would be a lot easier to install if there was a trunk line to the green that could be easily tied into, and so we wouldn't have to get the drainage underneath the irrigation loop after the irrigation was already in.  [Rule No. 2 of construction:  it's cheaper to fix drain tile than irrigation pipe.]  But, I understand what you are saying about having the low pressure to draw the water out ... we've buried loops of tile under the depressions on several of our courses [instead of bringing the tile to a grate at the surface], and it is amazing how fast the water gets sucked through the sand.

Incidentally, it may be of interest that on a few courses we've done, our agronomist recommended that we have MORE than 12 inches of sand for our greens mix, because of the particle size and its water holding capacity.  I don't know if this sand would have passed the USGA specs or not -- if it did, how would it work in a twelve-inch profile?  But using 20 inches of sand that was available on site was a lot more cost-effective than building greens with 12 inches of sand trucked in from somewhere else.

[TEPaul]

"Quote from: Kyle Harris on February 07, 2010, 08:44:44 AM
Quote from: TEPaul on February 07, 2010, 08:11:29 AM
Mike:

Do you know Armen Suny?


Seems like someone better suited to growing grass than writing. That was a tough read.


Could you point to something you have written?"





Tom MacWood:

First of all, why exactly did you ask Kyle Harris that last question?  

Second, since Kyle Harris didn't point to something he's written and may not, then I will do it for him. Read his posts #9, #10, #15 particularly, for starters. I very much doubt you'd ever be able to write something like that on this subject but if you think you can then why don't you try to? 

Jeesus guys, this is some amazing thread for the agronomic layman like me. Thanks a lot----now I'll have to spend the next hour or two reading this entire thread to try to understand even a modicum of this important subject.

Good going, this is the kind of thread that helps make a site like this one a great resource entity for people like me.


PS:
By the way, since asking Mike Young on the first page if he knew Armen Suny, Mike gave me his number and in the last three days I've had a couple of just wonderful hour long conversations with Armen about architecture and particularly about his experiences with Merion's Richie Valentine beginning about thirty years ago. Armen has a total wealth of personal information on Richie, his methods and the maintenance nuances of Merion back then. That's thirty years ago. Who else is around who can provide that personal info? Probably nobody we can find and so for that reason alone Armen is eminently debriefable on that subject alone and Merion is going to do that with him hopefully via audio or video and then put it into their already impressive archives!

Thanks MikeY and thanks Armen-----it all began here.  

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