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Abgeschickt von Holger Perner am 20 Januar, 2005 um 13:43:57
Antwort auf: Dune Sand von Gerhard Stickroth am 18 Januar, 2005 um 12:51:56:
Dear Mr. Stickroth,
I listed dune sand in the cultivation part of „The Genus Cypripedium" because it was and still is one of the two main ingredients of the Cypripedium substrate of Charles (‘Chuck’) Sheviak who some time ago also wrote in this forum about his cultivation methods. Your conclusion of what dune sand is: ‘...any sand blown to form a dune’ is absolutely correct! The horticulturist has to decide about the specifics of the sands exact composition according to the plants he wants to grow. Lime free sand composed of nearly nothing else but quartz reacts acidic when humus is included, thus acidic sand means inert quartz sand particles mixed with material providing organic acids. The very same sand mixed with lime, i. e. calcium carbonate, reacts neutral to slightly basic, such a lime-delivering ingredient can for example be crushed oyster shells. Any kind of mollusk shell will do but under that very name it can be purchased in English-speaking countries for poultry farming, in Germany it would be called ‘Muschelgrus’. Chuck is using dune sand because this sand is freely available along the Hudson river flowing through Chuck’s hometown Albany in Upstate New York. The same kind of sand can be found for example in the dunes along the river Elbe east of Hamburg, Germany, where I grew up. However, any kind of quartz sand can be used, whether it is from a dune or other source.
Hope that explains the matter,
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