# green sand vs other sands



## keithrs (Sep 21, 2011)

Is there any benefit to green sand vs silica sand vs play sand for the use on orchids?


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## gonewild (Sep 21, 2011)

Why is the sand green?


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## cnycharles (Sep 21, 2011)

.... algae buildup


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## Rick (Sep 21, 2011)

Green sand is a natural sand that has a strong affinity for iron and manganese when activated with Potassium permanganate.

Usually I see it called Manganese green sand.

I think it is reall high in iron and manganese content and is sometimes used as a horticultural soil ammendment for increasing iron content.

I use it in my lab for various water treatment things, but I've never used it for plants.

I know of one person who used it for ammending soil in a corn patch, and corn looked good this year.


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## cnycharles (Sep 21, 2011)

didn't someone have a thread here where they tried to determine what might be the best nutrients for paphs, and how they reacted possibly to modern fertilizers... I think one conclusion from leaf tissue testing was that some paph species might be overloaded with iron from modern fertilizers? if so, then green sand might not be good for paphs, unless they were trying to not use modern fertilizers (and even then if paphs didn't like or need all that much iron, it might still be too much)


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## keithrs (Sep 21, 2011)

The stuff I have is more blueish green. It comes from glauconite(iron-potassium silicate)which was made from when NJ and Delaware where still part of the sea floor. It has a NPK of 0-0-3. Has iron, silica, magnesium, and about 30 other trace minerals. I use it in my garden beds.


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## gonewild (Sep 21, 2011)

Sounds like a great sand to add to the potting media. Based on what has been said I would try it.


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## Rick (Sep 21, 2011)

www.natureswayresources.com/DocsPdfs/greensand.doc

Here's an article on it with composition analysis.

No significant calcium. Lots of iron silicates and potassium. Characterized as a "slow release potash for iron poor soils".

If you use this in our standard bark or chc mixes in conjunction with a standard fertilizer I think your orchids will OD on potassium in a single growing season.

Standard fertilizers and more advanced orchid formulas already bury our plants in K and Fe, and bark and chc mixes hang on to sodium and potassium readily.

Probably great for annuals and food crops with an 9 months growing season, and then harvest at the end of the year. But this material would rarely be recommended for perennial crops and trees.

Try it as a light top dress on just a few disposable plants and let us know.


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## keithrs (Sep 22, 2011)

Actually, I do add a hand full along with other minerals around the base of my fruit trees and flowers beds to remineralize the soil...... Thats for a different day!!! 

Thanks for that link!!!! 

I'll give it a go.........


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## nikv (Sep 22, 2011)

I guess I should read the thread titles carefully. Here I thought I was gonna see an abla sanderianum!


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## gonewild (Sep 22, 2011)

Rick said:


> If you use this in our standard bark or chc mixes in conjunction with a standard fertilizer I think your orchids will OD on potassium in a single growing season.



Based on this thought then this would be the perfect time to use Calcium Nitrate as the main nutrient in the fertilizer water. Use the green sand as a mixed part of the media and maybe use some form of rock phosphate as a top dressing. 



> Standard fertilizers and more advanced orchid formulas already bury our plants in K and Fe, and bark and chc mixes hang on to sodium and potassium readily.
> know.



Do you think the excess potassium concept applies equally to small seedlings or more towards mature plants?


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## lindafrog (Sep 22, 2011)

I've used greensand in potting mix for phrags and other orchids. Can't say for sure it was the greensand but the seedlings did great. Try using 1/4 teaspoon for gallon of mix.


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## gonewild (Sep 22, 2011)

lindafrog said:


> I've used greensand in potting mix for phrags and other orchids. Can't say for sure it was the greensand but the seedlings did great. Try using 1/4 teaspoon for gallon of mix.



Wow, I was thinking more like a cupful in a gallon of mix? Does the green sand dissolve?


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## Rick (Sep 22, 2011)

gonewild said:


> Based on this thought then this would be the perfect time to use Calcium Nitrate as the main nutrient in the fertilizer water. Use the green sand as a mixed part of the media and maybe use some form of rock phosphate as a top dressing.
> 
> 
> 
> Do you think the excess potassium concept applies equally to small seedlings or more towards mature plants?



That would be a way to balance the system Lance. Make the Ca and N cheap and easy for the plant to get and make it fight for the K. It could work.

I think it applies to small seedlings too. I've had plenty of seedlings grow great for the first few months to a year out of flask and then stop. Followed by a couple years of trickling losses to various rots. This was particularly bad for multifloral and brachy species.


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## Rick (Sep 22, 2011)

gonewild said:


> Wow, I was thinking more like a cupful in a gallon of mix? Does the green sand dissolve?



This stuff doesn't break down that fast. Probably no faster than oyster shell. But if positive effects at 1/4 tsp per gallon of mix then this is potent stuff.

The amount of iron is also considerably higher than the K if I recall. And it doesn't take alot of iron to get plants happy if they are in need of it.


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## Ray (Sep 23, 2011)

As a ceramic engineer and scientist, I am used to thinking of most of these inorganic additives as basically being insoluble, so it makes me wonder if their use truly adds anything to the plants' nutrition. As examples, silica is one of the least soluble minerals on the face of the earth (hence beaches), and I cannot come to terms with what I expect to be a minimal contribution by oyster shell top-dressing, as compared to the amount of calcium added by some fertilizers.

Are there any pour-through, or other measurements that show their presence, or is the evidence anecdotal only?


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## Roth (Sep 23, 2011)

Green sand was said to be a 'magic ingredient' by several well known paphs grows, Carl Orff, Walter Bertsch...

There are downloadable VERY interesting PDFs here:

http://www.aosforum.org/pdf/

Especially the 3 papers Growing Paphiopedilum by Walter Bertsch

( who was incidentally apparently the one who introduced to Morel and Vacherot and Lecoufle some other research being carried on in the USA to tissue culture orchids...).



Ray said:


> As a ceramic engineer and scientist, I am used to thinking of most of these inorganic additives as basically being insoluble, so it makes me wonder if their use truly adds anything to the plants' nutrition. As examples, silica is one of the least soluble minerals on the face of the earth (hence beaches), and I cannot come to terms with what I expect to be a minimal contribution by oyster shell top-dressing, as compared to the amount of calcium added by some fertilizers.
> 
> Are there any pour-through, or other measurements that show their presence, or is the evidence anecdotal only?



Well, a lot of things can be solubilized by acids, both mineral and organic acids, some bacteria and lower organisms have the capability to dissolve funny things ( think about Pseudomonas reactants). 

Some orchids have a very high content of silica (dendrobium jacobsonii comes to mind), so they have to get it from somewhere anyway. Same for others compounds. 

As non anecdotal, I made some flaskings using two different media ( one is used now in Germany). One was a standard all soluble media for the mineral base. The other one has calcium carbonate. When autoclaved, the calcium carbonate pecipitates at the bottom of the flask. The analysis of the media on top is definitely the same ( or nearly so, the calcium carbonate apparently locks a bit of iron, but not in significant quantities), pH the same. Well, when the roots reach close to the calcium carbonate coating, they just double in size for brachypetalum, the plants start to become green, and grow at light speed. That coating disappears as well on the path of the roots, about 1 cm left and right of the roots...


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## gonewild (Sep 23, 2011)

Roth said:


> Well, when the roots reach close to the calcium carbonate coating, they just double in size for brachypetalum, the plants start to become green, and grow at light speed. That coating disappears as well on the path of the roots, about 1 cm left and right of the roots...



I think this is a very valuable point for everyone to consider. For plants that grow on or in limestone I think it is very beneficial for the roots to contact a "limestone like" calcium containing solid. I think root contact with the solid is far better than relying on dissolved minerals from a top dressing.

During my growing experiments with P.kovachii I tested for exactly this situation and found the results positive. Plant and root growth were noticeably improved when the lime material was mixed into the root zone as compared to top dressed. I also did not see any difference between crushed limestone and oyster shell.


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## keithrs (Sep 23, 2011)

What about the use of calci-sand or calcium sand thats used for reptiles? Not sure if it granulated calcium carbonate or just mixed in to sand.


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## gonewild (Sep 23, 2011)

keithrs said:


> What about the use of calci-sand or calcium sand thats used for reptiles? Not sure if it granulated calcium carbonate or just mixed in to sand.



It might be coral or beach sand. I would worry about sodium content.


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## cnycharles (Sep 23, 2011)

there are crushed corals for the aquarium people that are made from fresh-water (inland) sources in florida and have no salt

this all said, (about beach sands and salt) I bought some beach sand at lowe's a few months ago and washed the heck out of it until there was no runoff from repeated washings, and I measured the tds until I read no difference in the water going into the bucket and the water leaving the sand. I used this sand, but now have a feeling that there is still salt leaching out as some of the plants just don't 'look right' and one paph delenatii that was growing very steadily is now going backwards after I did nothing but add sand to the top of the pot and sifted it in (and the plant dries out between waterings)


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## Rick (Sep 23, 2011)

keithrs said:


> What about the use of calci-sand or calcium sand thats used for reptiles? Not sure if it granulated calcium carbonate or just mixed in to sand.



If you are heading to Pet Smart go to the aquarium section and pick up a bag of the white version of CaribSea Cichlid Sand. It has a hefty contribution of aragonite (close to pure calcium carbonate but softer than calcite).

Also this stuff is down to sand size in texture, so can be added as a top dress, and will sift down into the media fairly readily.

I've been using it mixed with the standard play sand at roughly 10:1 and using it in the baskets and a few other potted paphs. Its also in the mix with my baby kovachii.


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## keithrs (Sep 24, 2011)

Rick said:


> If you are heading to Pet Smart go to the aquarium section and pick up a bag of the white version of CaribSea Cichlid Sand. It has a hefty contribution of aragonite (close to pure calcium carbonate but softer than calcite).
> 
> Also this stuff is down to sand size in texture, so can be added as a top dress, and will sift down into the media fairly readily.
> 
> I've been using it mixed with the standard play sand at roughly 10:1 and using it in the baskets and a few other potted paphs. Its also in the mix with my baby kovachii.



Good to know!! Do you still give calcium nitrate?


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