what is the impact of using very fine sand in topdressing ???

[Scott Coan]

Bob's interview on bunkering brought this question to mind, so I hope some of the superintendants out there can shed some light.

My course is built on sand and we have a quarry on site that supplies all our bunkers.  It is incredibly fine sand, almost the consistency of talcum powder.  It is quite natural and fits in perfect as it's basically the stuff that the whole course is built on.

My issue is not with the bunkers but with the greens.  We have been using this same sand for our topdressing after we core our greens and I am wondering if this has led to some problems.

Almost all the great greens I've played on seem to have very course sand as an underlay.  You know how when you repair your ball mark and can actually feel and hear the scrunching of sand particles underneath?

Thanks for any insight into this issue.

[Sean Remington (SBR)]

Scott,

  If your course is built on this material and you mine the same stuff to use for topdressing I don't see a problem. Are turf conditions suffering? If not someone must have made a correct determination that turfgrass would grow on your native material. How cool is it to have your own quarry?

[Scott Coan]

Sean,

The turf on the greens is just way too soft, to the point of being spongy.  I am wondering if this may be caused by the use of the fine sand.  We have instituted an aggressive coring regime in just the last couple of years and have been topdressing exclusively with this fine stuff.  Prior to this the greens were not cored for 5 years!

Having the quarry is pretty cool as we are never lacking for sand.  In fact we just put in a new bunker and all they had to do was basically dig a hole and we had a bunker.

[Donnie Beck]

Scott,

Stop using it immediately!  You never want to topdress with a finer material than what the greens were built with. The fines will clog the pore space and you will have BIG time problems with water infiltration and drainage.

[Jeff_Brauer]

Scott,

What Donnie said generally applies.  I also wonder if you had done any topdressing with it before the coring program? Did your topdressing go pure sand, or did it have some brew of organics in it?

Sometimes, a layer develops at the interface of old and new sand, just an inch or two below the surface, holding water too near the surface.  IF the sand is as fine as you describe, I suppose its also possible the water is coming back up in part due to wicking action, although the layer holding water would be the most common problem of squishy greens.

The coring should help ,if this is the problem, gradually cutting through the layer, but as Donnie says, equal sand to original construction is best, coaser sand next best, and fine sand often a recipe for disaster.

[Dan_Lucas]

It is easy and inexpensive (considering the importance) to send samples of your sand AND your green soil profile to a reputable lab for testing. Check your fertilizer vendors or University if you need help in choosing one. They can very accurately analyse your soil and sand and tell you what to expect both short and long term.

Ultra fine sand can seal up the porosity of a green very fast. Too coarse also can create problems. If the greens were very soft without overwatering (especially without aerifying) the sand particles may be too rounded (like walking on marbles). You need to have a percentage of jagged particles in the mix to help it bind together and firm up.  

[SL_Solow]

To deal with the organics issue, we have kiln dried sand for top dressing.  The kiln drying produces a fine sand and removes organics.  i do not believe we use this sand to fill deep coring and I defer to the professionals on that issue.

[Sean Remington (SBR)]

I made the assumption that your greens are constructed out of the same material that you say is quarried on site and used in the bunkers. Also, the assumption that this material was tested prior to construction.

As has been stated, get some testing done. I like the International Sports Turf Reaserch Center (ISTRC). They can so a core sample test that will produce very valuable information that may help determine what's going on with the greens.

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