J.E. Shields jshields104@comcast.net
Wed, 07 May 2008 16:14:59 PDT
Jim McK.,

I'm happy to oblige.  What we are seeing here is cultural (not to mention 
scientific) lag.  Using "potash" in place of the proper name for the 
element, potassium, is left over from the 18th century.  Which seems to be 
about where some horticulturists and all gardening magazines still 
reside.  (Ouch!)

The terms "sulphate of potash" and "muriate of potash" are simply archaic 
names for potassium sulfate and potassium chloride.  There is no "potash" 
(K2O) hidden in the sulfate.  Personally, I have a heck of a time figuring 
out what the N-P-K numbers ought to be for chemicals like potassium 
nitrate, ammonium phosphate, etc.   When I mix my own from lab chemicals, I 
end up with the metric numbers, not the silly American fictions.

You can tell the difference between cheap and premium fertilizers by 
reading that fine print.  If they use potassium chloride (KCl) as the 
source of potassium, it's cheap stuff.  If they use sodium phosphate, it is 
even worse quality (and even cheaper).

Jim, I'll go off on a tangential rant if I don't quit now!  If you have any 
more questions, drop me a note later.

Best to all,
Jim Shields
ranting and raving in central Indiana (USA)  over the scientific illiteracy 
of certain parts of the world

At 06:32 PM 5/7/2008 -0400, you wrote:
>Jim Shields, if you don't mind, let's continue the inorganic chemistry
>If, as you say, potash is literally the potassium containing residue of
>burned wood, are there such things as sulfate of potash and muriate of
>potash? And if so, are they different in some way from potassium sulfate and
>potassium chloride? I'm not asking you if the names exist - we already know
>that these terms are common, at least in the older gardening literature. I'm
>asking if there is such a thing as sulfate of potash which is distinct from
>potassium sulfate and a muriate of potash which is distinct from potassium
>Jim McKenney

Jim Shields             USDA Zone 5             Shields Gardens, Ltd.
P.O. Box 92              WWW:    http://www.shieldsgardens.com/
Westfield, Indiana 46074, USA
Tel. ++1-317-867-3344     or      toll-free 1-866-449-3344 in USA

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