Errr, strictly speaking, potash is KCl, not potassium sulphate (unless the term potash is being used very loosely?)
Potash is mined on a huge scale in the neighboring province of Saskatchewan, from the Devonian Prairie Evaporite Formation, for plant fertilizer. I'm not sure why the concept of "organic" (albeit, an artificial term, but in the sense it seems to be meant) would not apply to naturally-occurring minerals (which are however in the other sense of the word, inorganic)... ?