# Sand anybody?



## Rick (Nov 12, 2010)

I was reading John Doherty's article on P. sanderianum (and hybrids) in Orchids.

A lot of his culture overlaps mine for multis, but I was intrigued about his use of sand as a biannual top dress (with oyster shell).

I have sand in some bark mixes with some of my barbata types (using Lance Birk's "pretty good" mix) and have had some individual plants do very nice in it.

I know a couple of growers in my local society will mill their bark with sand, which seems to make the bark last a lot longer and drains better.

Some of the "soils" that some of the barbata are found in often have sand listed in the description.

Normally I think of sand as something totally inert, and just a drainage aid, but do you think it could be a source of silicates?

I use Protect on a fairly regular basis, which is potash, but with a good source soluble silicates.

Any opinions?


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## Ernie (Nov 12, 2010)

Rick, we've been adding sand to our bark mixes, particularly for slippers, for the last several years too. Probably read it somewhere and decided it wouldn't hurt. Since, we've noticed root hairs like to grab onto it... or does the sand just stick in the hairs. Who knows. I've also read many conflicting accounts of various "silicious" media contributing Si to plants. Sand is essentially glass. When was the last time your window dissolved?  I dunno. There's probably more chemistry to it. I doubt the sand provides much Si, and probably way less than soluble ProteKt. But, if it makes you feel good, do it (as long as it's not counter productive!). Don't use fine sand, it'll make cement when it packs and gets wet. We use pool filter sand which is pretty coarse.


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## Eric Muehlbauer (Nov 12, 2010)

I think that the use of sand goes back to a mix that Ray Rands published a few decades ago. He said that the sand opens up the roots by getting between the root hairs (or are they more like scales?) and keeping them open, and, as Ernie said, giving them something to "grab on to."


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## cnycharles (Nov 13, 2010)

jim marlow gave a repotting clinic last september and he showed us a paph that had sand in the media, and the sand had collected to the root hairs and the roots looked pretty happy. I wonder if it helps to keep the hairs a bit moist but keeps large droplets from bridging the root hairs and stifling things?


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## Jim Toomey (Nov 13, 2010)

Hi Ernie,
Do you have a particular place that has good prices on sand?
I'm here in Maitland.
Thanks,
Jim


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## Ernie (Nov 13, 2010)

Jim Toomey said:


> Do you have a particular place that has good prices on sand?



Home Depot. Look in the pool section- it's outside with the garden stuff at ours in Waterford Lakes. It's a 50-60 lb bag for about $4-5. If you ask the employees, they'll probably send you to construction materials for play sand. If you need to ask, ask for pool filter sand.


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## Jim Toomey (Nov 13, 2010)

Thanks!
I've looked before at mulch,dirt type dealers but they want to sell by the truck load.
50-60# bag much more manageable.


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## cabnc (Nov 13, 2010)

Ask an associate at TheHomeDepot, they probably have a 'busted' bag on the side. Then you can get less than 50# and a much reduced cost.

Charlie


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## Candace (Nov 13, 2010)

A couple of paph growers in my area put sand in their mix for the reasons stated above. I added some sand to my CHC mix this year. I figured it can't hurt.


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## Lance Birk (Nov 13, 2010)

When I first made my "Pretty Good Mix" in 1964 I was always puzzled by the fact that so many root hairs stuck to the particles of sand. Since I recently began to publicly sell my mix I have done more research and can offer more clarity.

In my grower's manual I said that silica sand can be used as a substitute for "washed river sand" which is the same as is used to make cement, or plaster. It's not quite the same. Straight silica sand provides aeration and a point of attachment for nutrient uptake. River sand however, contains a multitude of nutrients, as well as silica sand or quartz, which supply necessary micro-nutrition for our plants. Closer examination shows root hairs attach to other ingredients contained in the sand besides the impervious particles. This is why, I found, that I hardly ever needed to fertilize once I began using this mix for all types of my orchids. Although I have not examined many other sources of 'river sand' I am confident that most other sources around the world will be similar in practice.

Lance Birk


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## gonewild (Nov 13, 2010)

Lance Birk said:


> Straight silica sand provides aeration and a point of attachment for nutrient uptake.
> Lance Birk



Can you clarify what you mean by "point of attachment for nutrient uptake"?


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## likespaphs (Nov 13, 2010)

also, would you please clarify washed river sand or where to find it?


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## Lance Birk (Nov 13, 2010)

The point of attachment is just that. It is where the root hair attaches to another body which then allows a 'solid base' from which nutrients can be readily 'up-loaded'. Rather than leaving that root hair just dangling in space, so to speak, other objects such as solid quartz particles as well as absorbent organic particles provide an attraction to which fertilizers, nutrients, etc., will attach. I'm certain you have seen how they work; root hairs always seem to attach to 'something'!

The washed river sand is readily found in home improvement centers, garden supply centers and your local building materials place. As I said, ask for the sand used to make cement (concrete) or plaster..... They call it "washed" but clays and other elements that make up "soil" are always in there.


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## Eric Muehlbauer (Nov 13, 2010)

How would the aragonite (such as Southdown brand) sand that is sometimes sold at places like Home Depot be? Its fine sand, pure calcium carbonate...I use it in my reef tanks. I doubt it would be good as the only sand source...maybe too basic, but how about if it were combined with more typical silica sand sources?


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## chrismende (Nov 17, 2010)

Thanks for the clarification, Lance! I've just been re-re-re-reading your second edition in the cultural sections. And specifically about the sand and moss.
I know that Terry Root uses sand in his mix, too.


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## TyroneGenade (Nov 17, 2010)

Ernie said:


> ...If you need to ask, ask for pool filter sand.



Do NOT ask for pool/building filter sand. This type of sand is normally acid washed. The acid dissolves out the micronutrients but this is beside the point. The acid washing allows the sand particles to link up via silicate bridges causes the sand to cake-up. Plants do not like this. Read http://www.apsa.co.za/board/index.php?topic=4337.0 for some experiences with pool filter sand for growing plants.

tt4n


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## labskaus (Nov 17, 2010)

So you guys are talking about two different things:
Sand particles that may offer physical effects while being chemically inert, like Quartzite, and the clay particles which are part of most sands and which may give different chemical effects in the medium (buffering, ion exchange,...).

Sand is so difficult to describe and to standardize. I think its a try and error thing.


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## Ernie (Nov 17, 2010)

TyroneGenade said:


> Do NOT ask for pool/building filter sand. This type of sand is normally acid washed. The acid dissolves out the micronutrients but this is beside the point. The acid washing allows the sand particles to link up via silicate bridges causes the sand to cake-up. Plants do not like this. Read http://www.apsa.co.za/board/index.php?topic=4337.0 for some experiences with pool filter sand for growing plants.
> 
> tt4n



Interesting. The pool filter sand we use is MUCH more coarse than the builder's sand available here. Our pool filter sand does not cake either. On the contrary, it flows quite well compared to other kinds of sand we've tried. We tried builder's sand and (foolishly) play sand and both accumulated in the bottoms of the pots and essentially made cement- not cool. Whereas the pool filter sand stayed within the bark mix bed much better. As far as micronutes, I can live with that. 

What types of sand are other folks using successfully here in the US?


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## Rick (Nov 18, 2010)

Since I took it home from work I can't remember if it was play, or building sand. It was cheap stuff from Home Depot. I've used it for a lot of plant stuff, and at work I use it as a component of artificial sediment for toxicity testing.

It's pretty dusty, so it does get washed before use. However, the grain size is pretty big compared to the super fine "silica" sand. Maybe a 1/4 of a millimeter??

It also flows well and does not compact. I think the compacting issue is more due to the smaller grain size so you get tighter physical packing between particles.


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## Rick (Jan 25, 2011)

The other day I thought I saw a post that said that white versus yellow play sand was dangerous because it would raise the pH of the mix.

Since I ran out of the yellow sand a couple months ago, and did a bunch of stuff with whiter sands, I did a check in the lab today.

1) A couple of tbs of a white sand (Quickcrete Play sand) in about 50 ml of distilled water turned the pH to 9.0

2) rinsing in more distilled water about 3 times and the pH dropped to about 8.8

3) One rinse in tap water (pH about 7 )and leaving the tap water in place, the pH stayed at 7.

4) replacing the tap water with distilled water allowed the pH to go back up to 8.8

It appears that there is a weak source of alkalinity in this white play sand, but it is not alkaline enough to change the pH of a moderately buffered system (Nashville tap water is only moderately hard with an alkalinity of ~ 50mg/L as CaCO3). Since I am using it in rather small quantities in bark or moss based mixes (which are somewhat acidic), it will have either no effect or slightly beneficial effect of buffering the most acidic pots.


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## SlipperFan (Jan 25, 2011)

So, how about if I go to Lake Michigan and scoop up some of the sand from the dunes?

Or pick out some sand from the bottom of the little river that goes through the back of our property?


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## Rick (Jan 26, 2011)

I carried the experiment one step further, which overlaps with my sphag/basket potting method I'm trying.

I took a 4 inch basket with a recently potted roth seedling in it (which has grown about 20% since potting up).

The media makeup in this basket is:
1) at least 80% by volume sphagnum
2) about 20% hydroton pellets
3) about 1heaping tablespoon of white play sand
4) about 1/4 tsp of "Cichlid sand" (an aquarium buffering sand).

Using my misting wand I applied my irrigation water until I collected about 100 ml of water dripping from the bottom of the basket.
Irrigation water chemsitry:
1) pH ~ 7.5
2) conductivity about 40 useimens/cm
3) hardness ~ 20
4) alkalinity ~10

My irrigation water is about a 10:1 mix of lab grade RO water and my household well water.

The chemistry of the water dripping out of the basket:
1) pH = 6.2
2) conductivity = 300
3) hardness = 60
4) alkalinity = 19

Slight yellow color.

These are numbers that look optimal for nutrient/mineral uptake by orchids, and its apparent that the white play sand (or the dash of Cichlid sand) is not raising the pH to unsafe levels.


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## Rick (Jan 26, 2011)

SlipperFan said:


> So, how about if I go to Lake Michigan and scoop up some of the sand from the dunes?
> 
> Or pick out some sand from the bottom of the little river that goes through the back of our property?



Probably wouldn't hurt:wink:


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## gonewild (Jan 26, 2011)

SlipperFan said:


> So, how about if I go to Lake Michigan and scoop up some of the sand from the dunes?



Probably a good source.



> Or pick out some sand from the bottom of the little river that goes through the back of our property?



Probably not a good source.

The dune sand would be very clean and free of organic matter.
The river sand may contain undesirable micro organisms and also fine silt.


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## gonewild (Jan 26, 2011)

Rick said:


> Using my misting wand I applied my irrigation water until I collected about 100 ml of water dripping from the bottom of the basket.
> Irrigation water chemsitry:



Another good comparison would be to collect the free water in the basket and test that. This would allow you to analyze the water that the roots sit in contact with and be less influenced by the fresh irrigation water.
About midpoint between waterings tilt the basket at an angle and some water should run out of the bottom. Collect from several different baskets and test that sample.


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## Rick (Jan 26, 2011)

gonewild said:


> Probably not a good source.
> 
> The dune sand would be very clean and free of organic matter.
> The river sand may contain undesirable micro organisms and also fine silt.



Depends where you are on Lake Michigan.

It may not be so great if you are down in the Chicago/Whiting/Gary end where all the steel mills are.

In either case it may not be a bad idea to boil it or wash/soak it in chlorinated tap water.


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## SlipperFan (Jan 26, 2011)

Thanks, guys! I'm a long way from Chicago. Next time I'm at Lake Michigan, I'll take a scoop and a sack.


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## Rick (Jan 27, 2011)

gonewild said:


> Another good comparison would be to collect the free water in the basket and test that. This would allow you to analyze the water that the roots sit in contact with and be less influenced by the fresh irrigation water.
> About midpoint between waterings tilt the basket at an angle and some water should run out of the bottom. Collect from several different baskets and test that sample.



Yup thought about that.

Unfortunately with the sphagnum moss acting like a sponge, it really doesn't hold significant interstitial (free) water. I might be able to squeeze a bit out. I also tried not to bias too much by "flushing" by applying water fairly slowly, and grabbing the first flush (rather than letting it dribble out for a while before starting collection). Figuring that this first flush would have been a mixture of old/equilibrated water and new water. Lots of ways to standardize the proceedure.

I also need to correct the incoming water chemistry. (Made a fresh and precise batch and took it to the lab).

pH = 7.04
conductivity = 115
Hardness = 51.2
alk = 33.


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## Lance Birk (Jan 29, 2011)

If you want the benefits of organic and elemental nutrients use the river sand. Plants will love it and will respond noticeably.

If you want silica sand without nutrients use the sand from the dunes.


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## cnycharles (Jan 29, 2011)

if you use the river sand, should it be baked to get rid of any unwanted micro-organisms?


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## Rick (Jan 29, 2011)

cnycharles said:


> if you use the river sand, should it be baked to get rid of any unwanted micro-organisms?



The world is full of micro-organisms so I usually feel its futile to achieve sterility, but you never know


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## gonewild (Jan 29, 2011)

Yeah you don't need to try to get rid of all the organisms.
Id you are using washed river sand like what is sold to mix with plaster or bagged sand there is no need to wash or sterlize it.

But if you are using sand that you collect I would suggest being careful about not sterilizing the sand. Because the sand is from a river it surely contains a high volume of fungi, nematodes, and probably even root eating insect larvae. 
Sand from dunes probably never had much terrestrial fauna growing in it and commercial river sand is usually dug from deep in the riverbeds where all organic matter has been gone for years and years.


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## gonewild (Jan 29, 2011)

Lance Birk said:


> If you want the benefits of organic and elemental nutrients use the river sand. Plants will love it and will respond noticeably.
> 
> If you want silica sand without nutrients use the sand from the dunes.



Some rivers cut through limestone mountains and some cut through volcanic mountains.
Are you considering all river sand as equal? 
Eastern USA vs Western USA?


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## Rick (Jan 29, 2011)

gonewild said:


> Some rivers cut through limestone mountains and some cut through volcanic mountains.
> Are you considering all river sand as equal?
> Eastern USA vs Western USA?



It's hard to generalize even at the level of east vs west of the Mississippi. Even in TN we have at least a dozen different geologies with sandstones, limestones of all kinds, and granitic areas. But TN could be special, it has more species of crayfish, freshwater fish, and freshwater mussels than any other state in the union reflecting the diversity of aquatic habitats in the state.


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## Lance Birk (Jan 30, 2011)

"Sand' does not come from limestone mountains.

If you anticipate gaining the benefits of using sand in your potting mix use the 'washed river sand' like I first described in my grower's manual from 1984.


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## smartie2000 (Jan 30, 2011)

i also have decided to use sand as soon as I get to repot  The results I have seen on the forum has shown.

I don't know if this is worth mentioning, my Cypripedium parviflorum growing in perhaps 50-70% sand had no root rot at all.


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## Rick (Jan 30, 2011)

smartie2000 said:


> i also have decided to use sand as soon as I get to repot  The results I have seen on the forum has shown.
> 
> I don't know if this is worth mentioning, my Cypripedium parviflorum growing in perhaps 50-70% sand had no root rot at all.



You don't have to wait for repotting, you could top dress now, and most of it will work its way into the matrix with shaking and watering.

One of the Phal experts in our society mentioned that it was a great life extender of bark and moss substrates (which I mentioned in the first post of this thread).


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## Rick (Jan 30, 2011)

Lance Birk said:


> "Sand' does not come from limestone mountains.
> 
> If you anticipate gaining the benefits of using sand in your potting mix use the 'washed river sand' like I first described in my grower's manual from 1984.



The creeks around here definitely have some sand in them, but you also trip over limestone boulders to get to the creeks in the first place.

Granted the creeks in the "limestone hills" around here more likely than not have solid bedrock bottoms with very little sand or gravel in them at all. As the grade declines you find more areas of cobble / gravel, and the big sand deposits are at the lowest gradient streams.

Since limestone is so soft, the finer particulates are composed mostly of hard silicates, which is probably pretty universal in "sand" from one river to the next.


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## Rick (Jan 31, 2011)

Some of the numbers on my irrigation seemed off compared to some older records I had for my well water, so I tried it again.

I pushed the dilution rate closer to 10:1 and got:

pH = 6.86
conductivity = 61
hardness = 25.6
alkalinity = 25

Here's a new one PO4 (orthophosphate) 1.25ppm.

Given something close to the 10:1 dilution rate that means that the conductivity of my undiluted well water is presently close to 700 useimens. Which is about 2X higher than I've ever recorded for it. 

The phosphate is a great bonus for regular watering, but once again with a 10:1 dilution that indicates I have 10+ ppm of phosphate in my well water! About 3X any historical amount I've measured in the past.


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## gonewild (Jan 31, 2011)

Is you well deep or shallow?
Where does the water column stand in the well, is it deeper than before?
Maybe you have more or less water in the formation so the mineral dilution is now different. Or could indicate that there is some new water source entering your well. When you see the chemistry of well water change it is wisse to look for possible contamination.


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## gonewild (Jan 31, 2011)

Lance Birk said:


> "Sand' does not come from limestone mountains.
> 
> If you anticipate gaining the benefits of using sand in your potting mix use the 'washed river sand' like I first described in my grower's manual from 1984.



OK forget limestome mountains if you think they don't make sand. 

Closer to your home how about sand from the Santa Ynez River which comes from marine deposits and sand from The Kern River which comes from granite.

Do you consider the sands from both rivers equal in their nutrient values for potting media?


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## Rick (Jan 31, 2011)

gonewild said:


> Is you well deep or shallow?
> Where does the water column stand in the well, is it deeper than before?
> Maybe you have more or less water in the formation so the mineral dilution is now different. Or could indicate that there is some new water source entering your well. When you see the chemistry of well water change it is wisse to look for possible contamination.



The well bore ~150 ft and pump sits at about 125'. We've only pulled the pump out of the hole a couple of times over the last 16 years we've been here and water was only ~60 ft down the hole (and that was in the middle of a drought when many wells were actually failing in the area. Rainfall in the last year was pretty high, and you might have heard we had record flooding in my neck of the woods last spring. Karst limestone is pretty crazy for fast changes when old solution channels break down, so hard to say. We haven't had any visual changes in clarity, or increases in "sand" coming through the pump.

I also need to check the well water straight up in case something is leaching out of the pump sprayer that I use for mixing and watering (although I thought I ran enough through to rinse out the hose). Since I ran fertilizer the day before.


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## gonewild (Jan 31, 2011)

Rick said:


> The well bore ~150 ft and pump sits at about 125'. We've only pulled the pump out of the hole a couple of times over the last 16 years we've been here and water was only ~60 ft down the hole (and that was in the middle of a drought when many wells were actually failing in the area. Rainfall in the last year was pretty high, and you might have heard we had record flooding in my neck of the woods last spring. Karst limestone is pretty crazy for fast changes when old solution channels break down, so hard to say. We haven't had any visual changes in clarity, or increases in "sand" coming through the pump.
> 
> I also need to check the well water straight up in case something is leaching out of the pump sprayer that I use for mixing and watering (although I thought I ran enough through to rinse out the hose). Since I ran fertilizer the day before.



If you can check to see how far down the water is now that might give you a clue if some aquifer has dried up or is producing more water.
Any chance surface flood water got into your well?
Is your backflow preventer (check valve) working correctly?

It wouldn't take much residue hiding in a hose to throw off your tests.


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## Rick (Feb 1, 2011)

gonewild said:


> If you can check to see how far down the water is now that might give you a clue if some aquifer has dried up or is producing more water.
> Any chance surface flood water got into your well?
> Is your backflow preventer (check valve) working correctly?
> 
> It wouldn't take much residue hiding in a hose to throw off your tests.



The well bore is only 4" in diameter with a steel cap supporting the pump, so its not easy to look down the well.

Well pump and presure tank seem to be working good (just got replaced less than 2 years ago), check valve would apear fine. Our house and well house are pretty close to the top of the ridge, and no errosion gulleys pointing at the well house, so no obvious surface water getting in (usually when that happens, your water will be obviously muddy too, which it's not).

The conductivity right off the house line did read 600+. The phosphate only read 0.12 ppm. So the erroneous phosphate value came from the pump sprayer, but my well water has increased in salinity. (At least since 2002)


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## Howzat (Feb 1, 2011)

I have been using ground limestone for 20 years. It is just like coarse sand. But i guess that it also releases a micro amount of calcium. I used to use chunky broken limestone in the mix. But ground lime stone is easier to get/buy in 25kg bag and only cost $12. It last me for years. I also notice that I do not have to repot every year. But every so often I top it up with a spoonful of the ground lime stone. Last year I decided to repot the lot. Some have been in the same pot for 3-4 years.


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## likespaphs (Jul 11, 2011)

i really want to add sand but i'd like to find a local source and i still don't feel confident finding the right sand at a home improvement center. web search at lowes for concrete sand gives some results but i don't know which is good and which is bad. paver sand?
please help!
thanks....


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## Rick (Jul 11, 2011)

likespaphs said:


> i really want to add sand but i'd like to find a local source and i still don't feel confident finding the right sand at a home improvement center. web search at lowes for concrete sand gives some results but i don't know which is good and which is bad. paver sand?
> please help!
> thanks....



I'm just using the "play sand" sold in any HD or Lowes. The first bag was white and did elevate pH in distilled water in the lab, but in the moss the pH boost was not noticeable. The newest bag (with the exact same labeling) is yellowish, and I haven't done any recent pH checks. I also have been adding some "cichlid sand" that I bought at Petsmart, which appears to be aragonite sand, which is known to buffer aquarium pH and provide calcium.


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## Jim Toomey (Jul 11, 2011)

I use play sand from toys are us... Nice big grains.

Rick, can you add to much sand to the mix?
I've been wetting the sphagnum and adding in PrimeAgra (since I still have a bunch) and perlite. It seems to be a pretty chunky mix, in a good way.
It averages to be 3 parts sphagnum and two (+) parts the inorganics.


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## Rick (Jul 11, 2011)

Jim Toomey said:


> I use play sand from toys are us... Nice big grains.
> 
> Rick, can you add to much sand to the mix?
> I've been wetting the sphagnum and adding in PrimeAgra (since I still have a bunch) and perlite. It seems to be a pretty chunky mix, in a good way.
> It averages to be 3 parts sphagnum and two (+) parts the inorganics.




It's all still pretty new to me Jim so we'll just have to see. Another way to consider this, is that when people grow SH its nothing but inerts (clay balls). So if we consider a continuum from pure inerts' to pure moss (and I have successful and unsuccessful experiences in both extremes) we will find the balance for individual species and plants for our particular growing circumstances (how is that for non committaloke:oke. 

But I think that's were the nutrition aspect comes heavily in to play. I have an emersonii that I have not moved into a basket, which is doing very well in a mix that's lost most of its organics, and is now mostly limestone chips, perlite and charcoal. The big growth came in when I boosted Mg and well water addition to my irrigation watering. I had some experiments at work with garden vegies (tomatoes, lettuce, and radishes) that had control plants grown in straight sand. They were puny in comparison to organic potting mix, but all produce edible size product.

So far I think my baskets are closer to 4:2 moss to inorganics and fairly dense rather than chunky.


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## Ray (Jul 12, 2011)

I would think sharp, horticultural sand would be better than "play sand" from a packing perspective. "Paver" sand might be a good alternative, but is likely ground up granite, not pure silica sand.


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## SlipperFan (Jul 12, 2011)

Where would one find horticultural sand, Ray???


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## Ray (Jul 13, 2011)

I used to be able to get it from local garden centers, but haven't seen any around for a while. It was sometimes known as "sharp sand", as it was jagged, crushed quartzite, rather than the weathered, rounded sand dug from beaches or sand pits.


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## goldenrose (Jul 13, 2011)

likespaphs said:


> i really want to add sand but i'd like to find a local source and i still don't feel confident finding the right sand at a home improvement center. web search at lowes for concrete sand gives some results but i don't know which is good and which is bad. paver sand?
> please help!
> thanks....





Rick said:


> I'm just using the "play sand" sold in any HD or Lowes....





Jim Toomey said:


> I use play sand from toys are us... Nice big grains.
> 
> Rick, can you add too much sand to the mix?....


Play sand is A-OK! I just did my bog garden, play sand is recommended, not paver sand which supposedly can have additives that could be harmful to CPs. If it's potentially harmful to CPs then I wouldn't consider it for orchids. How many times has reference been made to Lance's basic formula? (8 parts med.fir bark, 2 parts chopped moss, 1 part 16 mesh silica or river sand). There's a tried formula, why not use that as a starting point? Koopowitz's book has Nick's formula (7 parts small Douglas fir, 1 part clean construction sand, 1 part charcoal, 1 part coarse perlite), there's another but the question is what is considered construction sand?
Types of sand have been discussed here before & play sand has been in agreement with many members here.
Can one add too much sand, in my experience, yes. When repotting, I found that you have to be continually tossing the moistened mix. The sand is heavy & ends up at the bottom of the bucket if you don't. Some repot using dry ingredients, dry sand, do I need to tell you where that will end up? Anyway, if the sand remains more evenly dispersed thruout the mix that's great but get pockets or globs of sand and I didn't find that to be desirable, it's hard to describe but it can really throw off the watering for that one plant. I messed around for a couple of years with this type of mix, I don't think it's quite the answer for me but I don't know what is yet either or will I ever!?


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## likespaphs (Jul 13, 2011)

thanks everyone!
i'm just worried i'm gonna not be able to find what's recommended and get something that ends up toxic to the plants
would putting the sand on top of the media be okay (sorta like topdressing with oystershell) or would it not work its way through the mix?


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## Rick (Jul 13, 2011)

likespaphs said:


> thanks everyone!
> i'm just worried i'm gonna not be able to find what's recommended and get something that ends up toxic to the plants
> would putting the sand on top of the media be okay (sorta like topdressing with oystershell) or would it not work its way through the mix?



It works its way thru a pot of bark or through basket of moss (more slowly). But that's really how I introduce it to either system, and just water in.


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## SlipperFan (Jul 14, 2011)

Ray said:


> I used to be able to get it from local garden centers, but haven't seen any around for a while. It was sometimes known as "sharp sand", as it was jagged, crushed quartzite, rather than the weathered, rounded sand dug from beaches or sand pits.


I've heard of sharp sand. I'll have to look around.


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## NYEric (Jul 15, 2011)

OK. If I go to home depot or lowes, and no they are still not really in manhattan, what do i buy?


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## Ozpaph (Jul 15, 2011)

If you don't have a lot of plants, a pet or aquarium shop should have coral sand or shell grit. There must be one of those in Manhattan?


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## Rick (Jul 15, 2011)

Ozpaph said:


> If you don't have a lot of plants, a pet or aquarium shop should have coral sand or shell grit. There must be one of those in Manhattan?



Those materials will provide calcium, and some buffering. The sand we have been talking about in this thread is just plain old non reactive or buffering silicon based sand. But yes if you go to the aquarium section of Pet Smart you can usually find some type of non buffering silica sand too. That's were I got the bag of "cichlid sand" which has aragonite sand that will buffer and provide calcium, and I'm pretty sure I saw some non reactive sands from the same company (Caribsea) for regular fresh water aquariums that want lower pH.

The stuff I'm getting from HD is called "play sand" for kids sand boxes.

I don't think for the relatively small amount to ammend the potting mix it makes any difference whether its angular or smooth, white or yellow. Just something finer than gravel, but coarser than dust. Wash the dust out first.


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## SlipperFan (Jul 15, 2011)

I don't quite understand this. It seems to me that fine sand, like play sand or builders sand, would simply wash through the media. I've tried it on a very small scale, and it ends up on my greenhouse floor.


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## Rick (Jul 15, 2011)

SlipperFan said:


> I don't quite understand this. It seems to me that fine sand, like play sand or builders sand, would simply wash through the media. I've tried it on a very small scale, and it ends up on my greenhouse floor.



Must really put the water flow to those pots Dot.

Unpotting after a year or so I still have a noticeable amount of sand scattered in the media. Most is in the bottom 3rd of the pot. It seems to not go so far in the moss baskets.


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## NYEric (Jul 16, 2011)

Thanx for the info. I'll be going to NJ today after aos judging . There's a home Depot (with its Lowes counterpart) in every town!


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## goldenrose (Jul 16, 2011)

Rick said:


> ....The stuff I'm getting from HD is called "play sand" for kids sand boxes.
> 
> I don't think for the relatively small amount to ammend the potting mix it makes any difference whether its angular or smooth, white or yellow..





SlipperFan said:


> I don't quite understand this. It seems to me that fine sand, like play sand or builders sand, would simply wash through the media. I've tried it on a very small scale, and it ends up on my greenhouse floor.





Rick said:


> Must really put the water flow to those pots Dot.
> 
> Unpotting after a year or so I still have a noticeable amount of sand scattered in the media. Most is in the bottom 3rd of the pot. It seems to not go so far in the moss baskets.


My results are similar to Rick's. I do hand water. I have to question how beneficial it's been? I don't think I'd be going out of my way (or digging very deep in my pocket) to try it.


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## SlipperFan (Jul 16, 2011)

Rick said:


> Must really put the water flow to those pots Dot.


Perhaps -- I use a thin garden hose and a soft nozzle, but plenty of water comes out.



Rick said:


> Unpotting after a year or so I still have a noticeable amount of sand scattered in the media. Most is in the bottom 3rd of the pot. It seems to not go so far in the moss baskets.


Yes, I would think that sphagnum would catch it more than bark or CHC.


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## likespaphs (Jul 16, 2011)

okay. i'm almost ready to do it....but how much do i put in a 2.25" and a 4" pot?
is it okay to put a big tablespoon of crushed oyster in when i put in ____ sand?
i typically soak my plants so i wonder how it will get distributed through the mix


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## Rick (Jul 16, 2011)

likespaphs said:


> okay. i'm almost ready to do it....but how much do i put in a 2.25" and a 4" pot?
> is it okay to put a big tablespoon of crushed oyster in when i put in ____ sand?
> i typically soak my plants so i wonder how it will get distributed through the mix



Do you normally use oyster shell? If you do, I don't see any reason why you can't use both in combination of both.

I've stopped using oyster shell and started using the Caribsea "cichlid sand" partially due to lack of availability, and partially because its finer grained, cleaner, and easier to use. I can mix a small amount in with the regular sand, and it moves around pretty evenly. But if your irrigation water has a high pH and plenty of calcium already, it may not be necessary to add pH buffering sand. Just use less fertilizer or find a low potassium fertilizer. 

Sand is pretty inert so you can use lots of it relative to the usual amount of oyster shell you use. I probably end up applying about a heaping tsp of sand per 2" pot and a good tblsp per 4" pot or basket.

If the mix is relatively dry at the time of application, you can tap on the sides of the pot and it will work its way into the mix. You can also water it in. For sphagnum baskets you pretty much have to wash it in.


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## likespaphs (Jul 17, 2011)

great, thanks!
{guess what i'm doing when i get home from work....}
Rick, i do normally use oyster shell with all but parishii since it's an epiphyte.
oyster shell if highly accessible here. if i wanted, i could grab my own shells and process them myself...oh... those are clam shells. hmmm. 
a long time ago i got a couple small deli containers of shell, one with powder and one coarse. been using the coarse but may try the other too


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## Rick (Jul 17, 2011)

likespaphs said:


> great, thanks!
> {guess what i'm doing when i get home from work....}
> Rick, i do normally use oyster shell with all but parishii since it's an epiphyte.
> oyster shell if highly accessible here. if i wanted, i could grab my own shells and process them myself...oh... those are clam shells. hmmm.
> a long time ago i got a couple small deli containers of shell, one with powder and one coarse. been using the coarse but may try the other too



Shells is shells Likespaphs.

I've been adding some calcium sand to parrishii too ( to balance the potassium in the fertilizer). I think lowii (which can be found both epiphytically and lithophytically) may be a good test case. My best growth for lowii was always with lots of limestone (or oyster shell) in the mix. Trying to grow it more "epiphytically" usually resulted in good results for a season or two, and then chronic withering disappearing plant over the next few years until gone. I'm on my third batch of lowii seedlings (which I assumed would be super easy).

They grew up to about 3- 4" LS and would stop growing, and then start dropping one by one over the next few years to what seemed like various rot like conditions. Repotting would temporarily invigorate. This third most recent batch (which are from the same parent selfing as the first lost batch) is already exceeding this result. I already moved a couple of the fastest into single 4" baskets with moss, limestone and sand, and they are already pushing 6" leafspan.


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## likespaphs (Jul 19, 2011)

thanks

last question(s):
do i need to wash the sand first? if so, any recommendations how? just put some in a bucket, fill it with water, drain while reserving the sand and repeat?


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## Leo Schordje (Jul 19, 2011)

I just re-read this whole thread. The term 'sand' is like quicksand, when trying to sort through definitions. Each industry that uses sand puts different labels on the sands sold for their industry. Some have very specific uses. The consumer market makes very little distinction, what ever is cheap gets bagged and a label slapped on. Sometimes the label means something, often it does not. 

My approach is to not over-think this. It's not rocket science. (though I know we have a scientists few here)

Think about your purpose. 

For orchids in a mixed collection, (emphasis on mixed) you simply want a fine particulate for root hairs and mycorrhizae (if present) to grab on to and increase absorbtion area. Play sand will work fine. Any of the many crushed or mined silica products will work. River sand is ok except for extreemly sensitive plants like some carnivourous plant. Sand is a minor component, no need to worry about particle structure and air voids. 90% of us don't need to read further, it is that simple. 

If you are mostly raising terrestrials, like Paphs, and most of your species are calciphiles, crushed limestone, such as is sometimes sold, also crushed granite as in paver's sand also is just fine. Oystershell and crushed dolomite are all very usable. Any combination is fine, I add both oyster shell and play sand to the mix for my calciphiles, like stonei and bellatulum. In a way, this is even simpler than above. 

If you are raising sensitive plants, like carnivorous plants & Cypripediums, only the most inert of media can be used. Here you need to look at what is being sold as play sand. If it has a rusty color to it, it may have more iron and other ingredients than you may want. You really need something that is pretty much pure silica quartz. Some play sands are good, sand sold for the outdoor cigarrette ashtrays tends to be very pure white, and cheap, this is pure silica. Those would work fine as a minor component. 

But for a carnivorous plant soil or a sand based soil for cypripediums, where the sand is a major component (over 20% of the mix) you need some structure and air voids. Here the sharp sands available at a builders supply house would be helpful. Same place or a machine supply house like Grainger, would sell silica for sand blasting. Here the particle sizes are graded, and you can get very specific size particle. These supply houses are not orientated to the consumer. You will only see them listed under wholesale or manufacturing supply. Designing soils is a really complex topic, wander over to bonsai info on the net and look at the information about inert or inorganic bonsai soils. Be prepared for hundreds of pages on the topic, but much of it is good.

*Rose*, just south of you on Hwy 12, is McCann Ready Mix and Concrete Supply. You can get sharp builders sand there, also various pure graded silica quartz. (I've used the Wedron 10-40 by Unimin Corp, because I used to get it for free) I think McCann is still in business? If not try the Meyers Material yard at Hwy 41 & Hwy 137 by Great Lakes Naval Base. I think there are Ozinga and maybe a Prairie Ready Mix yard on Hwy 12 also. You could go west on 173 to the Theilen's Quarry west of Richmond, head to the office, don't use the truck entrance. If they are busy, they might not want to make time for you. My name won't help your there. 

All these places are commercial / industrial. They usually are open week days only. Avoid the early 6 am to 9 am rush. Get there before 4 pm or they will be closed. Bring a check book, credit card, or cash, with the ability to make some change yourself. They mostly deal with companies on accounts, so they may be awkward in the way they handle cash customers. 

When searching for industrial sands check you local listings for 

Ready-Mix & Concrete Supply, also Concrete Block & Pre-Cast Supply
Brick, Block & Stone Supply (we have an actual brick yard the next town over from me)
Machine and Tool Supply (for sand blasting aggregates only)
Building Supply (Lumber yards often do not carry sands, but sometimes they do)
Landscape operations, not so much nurseries, but Landscape outfits that do excavation, you want to see earth movers, more than trees in burlap. 

Feed Stores, Poultry Supply - I frequently get my crushed granite for my bonsai soils at the local feed store. Ask for poultry grit. I prefer the Turkey Grit, because the granite is the same size as seedling bark, 1/4 to 1/2 inch. Grower grit is finer, 1/16 to 1/4 and Starter grit is very fine, less than 1/8th for chicks. Pigeon grit is crushed granite with both oystershell and some anise in it to attract the pigeons to peck, around 1/8 to 1/4 inch. 

Look for the word Supply, there are Ready-mix plants that do not sell anything other than ready-mix on the truck.

Hope these ideas help.
Leo


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## NYEric (Jul 21, 2011)

Leo Schordje said:


> IFeed Stores, Poultry Supply - I frequently get my crushed granite for my bonsai soils at the local feed store. Ask for poultry grit. I prefer the Turkey Grit, because the granite is the same size as seedling bark, 1/4 to 1/2 inch. Grower grit is finer, 1/16 to 1/4 and Starter grit is very fine, less than 1/8th for chicks. Pigeon grit is crushed granite with both oystershell and some anise in it to attract the pigeons to peck, around 1/8 to 1/4 inch.
> 
> Leo



I always love when the country folk post things like this! oke:


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