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Old 01-11-2008, 01:18 AM posted to rec.gardens.orchids
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Default cattleya leaf tip necrosis

I have a Cattleya that I bought as a bare root plantlet almost 5 years
ago. It has taken
a long time to get going, but is now growing well and sending its
first flower shoot. It
was probably too dry and underfed in previous years, because it (along
with my phals)
has responded very well to finer bark medium and a heavier feeding
regime. I'm now
using 200 ppm N in a weekly soak with made with a 20-20-20 + trace
elements fertiliser.

One of the Cattleya's leaves is black at the tip and it's
progressing. There is now maybe
15 mm of dry black leaf at the tip and then a band of chlorosis of 3
or 4 mm wide. Can
anyone offer an educated gues on whether this is due to salinity, lack
of Ca, a virus, or
something else? The fertiliser I'm using doesn't contain Ca, but the
water is very hard,
containing an average of 276 ppm of total hardness as CaCO3 according
to the water
company.


Leo

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Old 01-11-2008, 02:21 AM posted to rec.gardens.orchids
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Default cattleya leaf tip necrosis



wrote:
I have a Cattleya that I bought as a bare root plantlet almost 5 years
ago. It has taken
a long time to get going, but is now growing well and sending its
first flower shoot. It
was probably too dry and underfed in previous years, because it (along
with my phals)
has responded very well to finer bark medium and a heavier feeding
regime. I'm now
using 200 ppm N in a weekly soak with made with a 20-20-20 + trace
elements fertiliser.

One of the Cattleya's leaves is black at the tip and it's
progressing. There is now maybe
15 mm of dry black leaf at the tip and then a band of chlorosis of 3
or 4 mm wide. Can
anyone offer an educated gues on whether this is due to salinity, lack
of Ca, a virus, or
something else? The fertiliser I'm using doesn't contain Ca, but the
water is very hard,
containing an average of 276 ppm of total hardness as CaCO3 according
to the water
company.


Leo


It's not a virus.
Lack of Ca is unlikely with that water hardness. Low Ca usually shows up
as a dead spot near, but not at,the leaf tip. It shows up when the 2
halves of the leaf are still folded together, before the leaf opens up
flat. It usually starts growing bacteria which can kill the entire leaf
unless the bad part is cut off.
Salinity, or just too much fertilizer combined with the natural hardness
of the water could be the problem. This is not a problem I ever have to
deal with (super soft water here) but I believe it starts right at the
leaf tip on a leaf that is more mature than what I described above with
Ca deficiency.
What ever started it, it sounds like it now has a fungus working it's
way down the leaf. Cut off the bad part down past where it looks normal
and watch to be sure you stopped it.
Speaking of fungus, you described it as dry black, as opposed to wet and
rotted. That makes me picture antrhacnose. Anthracnose is more likely to
start at the leaf tips on thin leaved orchids like Oncidiums. Also it
usually starts out as spots and ends up dry tan/brown with a distinct
yellow line between the dead part and the green part. I'm not sure if
anthracnose affects Cattleyas but I sometimes have a Catt that gets a
dry brown leaf tip that may be it. I don't believe I've often seen dry
and black but sometimes I have.

Maybe something there will give you some ideas.

Steve in the Adirondacks

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Old 04-11-2008, 11:48 PM posted to rec.gardens.orchids
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Default cattleya leaf tip necrosis

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.




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Old 05-11-2008, 04:01 AM posted to rec.gardens.orchids
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Default cattleya leaf tip necrosis



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

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Old 08-11-2008, 02:03 PM posted to rec.gardens.orchids
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Default cattleya leaf tip necrosis

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





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Old 09-11-2008, 01:10 AM posted to rec.gardens.orchids
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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





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Old 09-11-2008, 02:09 PM posted to rec.gardens.orchids
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Default cattleya leaf tip necrosis

Duncan,

Once a compounds dissolve, they do dissociate, so I am uncertain of the
point of your comment about them.

In neutral pH, CaCO3 has a solubility of only about 14 mg/L in water.
Calcium bicarbonate is considerably more soluble, but it takes the presence
of a lot of free CO2 to form it in solution, and as the air only contains
about 0.03-0.04% CO2, you pretty much have to bubble CO2 through the water
to form appreciable amounts of the bicarbonate, or give it lots of time to
react and reassociate. Calcium nitrate, on the other hand, is about a
million times more soluble at about 1200 grams/liter. Given that, the ion
in solution - depending upon the pH and other dissolved species, of course -
will be the same, and is equally absorbable by plants.

Be careful how you read that water report. Instead of showing dissolved
ions individually, many municipal water systems report "alkalinity" in terms
of calcium carbonate content. In reality, it is the measure of the amount
of acid it takes to lower the pH a certain amount - a measure of the
acid-buffering capacity - and it is not a specific ion, but is made up of
carbonate and bicarbonates of a variety of cations, usually calcium,
magnesium and sodium. Based upon the solubility alone (14 ppm), it is
unlikely there is 130-250 ppm CaCO3 in your water supply, which would
provide about 50-100 ppm Ca - it's probably a lot lower than that, and if
you consider that in a 125 ppm N fertilizer solution (MSU RO formula), there
is about 75 ppm Ca, it's no wonder that in the water is insufficient.

There is some recent evidence that shows a plants' usage of Ca is determined
in part by the Mg present, as well.

--

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


"Duncan Vincent" wrote in message
...
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







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Old 10-11-2008, 12:16 PM posted to rec.gardens.orchids
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Default cattleya leaf tip necrosis


"Ray B" wrote in message
...

. . . In reality, it is the measure of the amount of acid it takes to
lower the pH a certain amount - a measure of the acid-buffering capacity -
and it is not a specific ion, but is made up of carbonate and bicarbonates
of a variety of cations, usually calcium, magnesium and sodium.



Best not use words I do not know, so I am staying away from cations. But I
think potassium could also be added to the list. Potassium bicarbonate is
commonly added to water to add alkalinity. J. R. Peters used to sell
straight potassium bicarbonate for use with their R.O. fertilizer
formulation. It has been replaced with a mix of calcium, magnesium, and
potassium bicarbonates.

Pat


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Old 11-11-2008, 11:48 PM posted to rec.gardens.orchids
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Default cattleya leaf tip necrosis

On Nov 9, 6:09*am, "Ray B" wrote:
Duncan,

Once a compounds dissolve, they do dissociate, so I am uncertain of the
point of your comment about them.


Umm, that's not quite true is it? For example, sugar (e.g. sucrose)
dissolves but doesn't dissociate. Sucrose will hydrolize but that's a
separate reaction from dissolution and requires a catalyst/enzyme or
heating for any significant hydrolysis to take place. Although in the
vast majority of cases compounds do dissociate when they dissolve the
point is that it is not true that dissolution = dissociation. While
not very relevant to the discussion his point is valid.

Dave

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Old 13-11-2008, 12:54 AM posted to rec.gardens.orchids
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Default cattleya leaf tip necrosis

It depends upon whether it is an ionically-bonded compound or not, doesn't
it?

--

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


"dbs" wrote in message
...
On Nov 9, 6:09 am, "Ray B" wrote:
Duncan,

Once a compounds dissolve, they do dissociate, so I am uncertain of the
point of your comment about them.


Umm, that's not quite true is it? For example, sugar (e.g. sucrose)
dissolves but doesn't dissociate. Sucrose will hydrolize but that's a
separate reaction from dissolution and requires a catalyst/enzyme or
heating for any significant hydrolysis to take place. Although in the
vast majority of cases compounds do dissociate when they dissolve the
point is that it is not true that dissolution = dissociation. While
not very relevant to the discussion his point is valid.

Dave





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Old 13-11-2008, 07:05 AM posted to rec.gardens.orchids
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On Nov 12, 4:54*pm, "Ray B" wrote:
It depends upon whether it is an ionically-bonded compound or not, doesn't
it?


That's the general rule that we were taught in General Chemistry ISTR.
But, if memory serves,
covalently bonded chemicals tend to be insoluble unless they have an
uneven charge distribution
spatially. Alcohols are an interesting group that dissolves but
doesn't dissociate due to the
hydroxyl group that introduces a spatial charge disparity.

My previous example of sucrose is an interesting exception to that
rule because they will
dissociate upon heating. Brewers use the fact that sucrose hydrolyzes
to produce an invert
sugar that has better fermentation properties (though an acid is
usually employed as a
catalyst). Cooks also "invert" sucrose by an addition of corn syrup
(aka fructose) while
heating a sucrose solution to prevent crystalization during cooling.

Dave


--

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

"dbs" wrote in message

...
On Nov 9, 6:09 am, "Ray B" wrote:

Duncan,


Once a compounds dissolve, they do dissociate, so I am uncertain of the
point of your comment about them.


Umm, that's not quite true is it? For example, sugar (e.g. sucrose)
dissolves but doesn't dissociate. Sucrose will hydrolize but that's a
separate reaction from dissolution and requires a catalyst/enzyme or
heating for any significant hydrolysis to take place. Although in the
vast majority of cases compounds do dissociate when they dissolve the
point is that it is not true that dissolution = dissociation. While
not very relevant to the discussion his point is valid.

Dave


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Old 14-11-2008, 04:08 AM posted to rec.gardens.orchids
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dbs wrote:
.......... Cooks also "invert" sucrose by an addition of corn syrup
(aka fructose) while
heating a sucrose solution to prevent crystalization during cooling.

Dave
.........................


In an effort to take this subject even farther off topic (If that's even
possible now):

Actually, corn syrup is glucose. We hear so much about the man
made/manipulated high fructose corn syrup these days that I can
understand the mistake. Probably the only reason we see so much high
fructose corn syrup around is because it is as sweet as sucrose and
cheaper due to our own government. They place a tariff on imported
sucrose and subsidize farmers who grow corn.

Steve
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Old 17-11-2008, 06:36 AM posted to rec.gardens.orchids
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Default cattleya leaf tip necrosis

It probably wouldn't hurt to soak the plant in a dilute solution
of calcium nitrate or calcium chloride. That would help draw out any
accumulated salts, and impart some known concentration of calcium.

Several years ago, I had some ICP tests done on orchid media
recovered from flasks with cattleyas suffering leaf-tip necrosis that was
characteristic of calcium deficiency. I don't have the values handy just
right now, but I recall the calcium levels were in the high-double digit
or very low triple digit parts per million level, and the cattleys were
showing the "terminal" signs of calcium deficiency.

The address in the header is bogus. Send no email there.

-AJHicks
Chandler, AZ


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Old 18-11-2008, 03:48 PM posted to rec.gardens.orchids
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On Nov 17, 6:36*am, (Aaron Hicks) wrote:
* * * * It probably wouldn't hurt to soak the plant in a dilute solution
of calcium nitrate or calcium chloride. That would help draw out any
accumulated salts, and impart some known concentration of calcium.

* * * * Several years ago, I had some ICP tests done on orchid media
recovered from flasks with cattleyas suffering leaf-tip necrosis that was
characteristic of calcium deficiency. I don't have the values handy just
right now, but I recall the calcium levels were in the high-double digit
or very low triple digit parts per million level, and the cattleys were
showing the "terminal" signs of calcium deficiency.

Thanks for this suggestion and also to Ray. Since the bedrock here
is calcium carbonate ('Southern England Chalk Formation'), I have
little doubt that the water hardness is mostly due to Ca++. The fact
that
it is expressed as CaCO3 in the report I cited is just an analytical
convenience. I imagine there's plenty of acid in the rain here to
mobilise
the Ca++. As Ray pointed out, if the hardness all Ca++, this would
put me in
the range of MSU RO formula. You observation indicates that under
some conditions this might not be sufficient.

Does anybody know of a source of MSU formula fertiliser in England (or
is the recipe available?)

Leo
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Old 19-11-2008, 09:45 AM posted to rec.gardens.orchids
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Default cattleya leaf tip necrosis

No fertilizer manufacturer is likely to share their formula, but by law they
are required to list the contents and percentages in the final formula, so
if you can figure out the makeup of the ingredients, it's fairly simple -
although time consuming - to reverse engineer it.

http://www.firstrays.com/MSUFert_RO.htm
http://www.firstrays.com/MSUFert_Well.htm

--

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


wrote in message
...
On Nov 17, 6:36 am, (Aaron Hicks) wrote:
It probably wouldn't hurt to soak the plant in a dilute solution
of calcium nitrate or calcium chloride. That would help draw out any
accumulated salts, and impart some known concentration of calcium.

Several years ago, I had some ICP tests done on orchid media
recovered from flasks with cattleyas suffering leaf-tip necrosis that was
characteristic of calcium deficiency. I don't have the values handy just
right now, but I recall the calcium levels were in the high-double digit
or very low triple digit parts per million level, and the cattleys were
showing the "terminal" signs of calcium deficiency.

Thanks for this suggestion and also to Ray. Since the bedrock here
is calcium carbonate ('Southern England Chalk Formation'), I have
little doubt that the water hardness is mostly due to Ca++. The fact
that
it is expressed as CaCO3 in the report I cited is just an analytical
convenience. I imagine there's plenty of acid in the rain here to
mobilise
the Ca++. As Ray pointed out, if the hardness all Ca++, this would
put me in
the range of MSU RO formula. You observation indicates that under
some conditions this might not be sufficient.

Does anybody know of a source of MSU formula fertiliser in England (or
is the recipe available?)

Leo




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