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Old 09-11-2008, 02:10 AM posted to rec.gardens.orchids
Duncan Vincent Duncan Vincent is offline
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First recorded activity by GardenBanter: Oct 2008
Posts: 17
Default cattleya leaf tip necrosis

hmmm my reply dissappeared. wasnt a very good one anyway. CaCo3 doesnt
dissolve very well were as nitrate does. I believe that the calcium in
water is actually calcium bi-carbonate and it can only exist in soloution.
My high school chem is a bit fuzzy but the ion logic sounds about right
however dissolved and disasociated arent the same thing. I grow Hydro and i
cant say absoulutly that calcium bi carbonate will not supply plants with
the amount of Ca they need. Our water here in Calgary is quite high in Ca(
130-250 ppm CaCO3 according to the water treatment plant) but i will get Ca
deficency if I dont add nitrate. According to Wikipedia CaCO3 reacts with
your stomach acid and turns into CaCl, which is soluble.

"Ray B" wrote in message
...
I agree with Steve.

Whether the source of the calcium is a carbonate or nitrate, in solution
the calcium is in the form of the ion Ca++, and that is absorbable by all.

--

Ray Barkalow - First Rays Orchids - www.firstrays.com
Plants, Supplies. Books, Artwork, and lots of Free Info!


"Steve" wrote in message
...


Duncan Vincent wrote:
The calcium found in water is almost totally unabsorbable by plants(or
humans for that matter). Makes my blood boil every time i see a tums
commercial telling people that it "contains calcium that your body
needs".
Calcium nitrate is very readily absorbed and is very cheap.



Really?? I'm surprised that you would say that.
I can't say much about plants and what they can absorb, in the way of
calcium. On the other hand, Tums is calcium carbonate I believe. The
calcium supplement that my physician wants me to take and the same one my
wife's doctor wants her to take uses calcium carbonate as the calcium
source.
I'm aware of the vitamin D connection and humans absorbing and using
calcium and I'm aware that calcium citrate is an alternative as a calcium
supplement. As I understand it, calcium citrate can be absorbed when
taken without food but calcium carbonate should be taken with food
because stomach acid is required to make it absorbable. I suppose people
taking strong acid suppressors would need to keep this in mind.
Sorry to emphasize the off topic half of your comments but if you are
going to convince me that Tums are not useful as a calcium supplement,
I'll need more information before I believe it. (Feel free to prove me
wrong. I like to learn.)

Steve