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  #1   Report Post  
Old 31-01-2003, 03:55 PM
germ
 
Posts: n/a
Default Languishing Paphiopedilum

I have a Paph. Transcolor that has not been growing well for a year
and a half. It was in a bark mix in a 5in plastic pot until 6 months
ago, repooted 6 months before that. I now have it in a coconut husk
mix in a 5 inch clear pot. The coconut mix is the one that I use for
all of my Paphs. ala Antec

The roots look good, they have grown since repotting. I tapped out
some of the mix and the roots are firm and fuzzy like they should be.
The three crowns of the plant have continued to grow, but they have
lost larger outer leaves in favor of smaller inner ones. The leaves
are waxy and small and light colored and they keep growing and the
outer ones keep falling!

This is a picture of the flowers and leaves of the second blooming
after I purchased it. (It was purchased in bloom, it bloomed again 6
months later, and then this blooming, its last in two years.)

http://members.verizon.net/~vze4xcmt...transcolor.jpg

I grew it in an east window indoors up until this fall. I tried
moving it under lights with the rest of my collection to see if that
would help, still no signs of improvement.

Thanks,
Jim

  #2   Report Post  
Old 31-01-2003, 04:27 PM
Gene Schurg
 
Posts: n/a
Default Languishing Paphiopedilum

Germ,

Interesting problem! You say that the roots are healthy and growing which
is the first suspect in a mystery such as this.

5 inch pot sounds a bit large but you didn't state the leaf spread so I
can't say for sure. But since the roots are growing well I assume this is
not the issue.

You mention the larger leaves are dropping and new smaller ones are
replacing them. I see this when a plant gets too much light and is
stressed. Doesn't sound like light is your issue since you moved the plant
under lights and before that it was in an east window. Hmmmm (could it be
the butler in the library with the candlestick?)

What a mystery....maybe it's the potting mix? no, you said you are using it
for other paphs.

Maybe the plant needs something you're not giving it? Is this one of the
paphs that need calcium in the mix? If this is the case the change of mix
would explain why it grew for a while and then started to fail. Check the
plant's parentage and see if it has calcelious (I can't spell) .....parents
that need calcium in their mix to enable them to take up nutrients.

Let us know what you find out.

Good Growing,
Gene






"germ" wrote in message
m...
I have a Paph. Transcolor that has not been growing well for a year
and a half. It was in a bark mix in a 5in plastic pot until 6 months
ago, repooted 6 months before that. I now have it in a coconut husk
mix in a 5 inch clear pot. The coconut mix is the one that I use for
all of my Paphs. ala Antec

The roots look good, they have grown since repotting. I tapped out
some of the mix and the roots are firm and fuzzy like they should be.
The three crowns of the plant have continued to grow, but they have
lost larger outer leaves in favor of smaller inner ones. The leaves
are waxy and small and light colored and they keep growing and the
outer ones keep falling!

This is a picture of the flowers and leaves of the second blooming
after I purchased it. (It was purchased in bloom, it bloomed again 6
months later, and then this blooming, its last in two years.)

http://members.verizon.net/~vze4xcmt...transcolor.jpg

I grew it in an east window indoors up until this fall. I tried
moving it under lights with the rest of my collection to see if that
would help, still no signs of improvement.

Thanks,
Jim



  #3   Report Post  
Old 31-01-2003, 07:23 PM
Steve
 
Posts: n/a
Default Languishing Paphiopedilum

Good thinking Gene, you could be right. Wildcatt lists Paph Transcolor
as 50% concolor, 25% rothschildianum, and 25% chamberlainianum.
Concolor is of course calcicolous and rothschildianum is not. I had to
look up the 3rd ancestor. I found this web site:
http://www.angelfire.com/or3/orchids...hlopetalum.htm which
contains this quote:

"Growing on limestone cliff faces near running creeks, and in water
seepage zones, it sought thick pads of humus and leaf detritus which had
accumulated against tree roots. While growing in limestone, Fowlie notes
they should not be cultivated on limestone chips, as the cooler water of
our temperate climates would allow greater dissolution of the limestone
particles, possibly furnishing toxic levels of calcium to the plants.
Naturally it receives bright but not direct sunlight."

I guess Transcolor is mostly calcicolous and should be supplemented with
lime in some form. I use a top dressing of crushed oyster shell, myself.

Steve in the Adirondacks of northern NY






Gene Schurg wrote:
Germ,

Interesting problem! You say that the roots are healthy and growing which
is the first suspect in a mystery such as this.

5 inch pot sounds a bit large but you didn't state the leaf spread so I
can't say for sure. But since the roots are growing well I assume this is
not the issue.

You mention the larger leaves are dropping and new smaller ones are
replacing them. I see this when a plant gets too much light and is
stressed. Doesn't sound like light is your issue since you moved the plant
under lights and before that it was in an east window. Hmmmm (could it be
the butler in the library with the candlestick?)

What a mystery....maybe it's the potting mix? no, you said you are using it
for other paphs.

Maybe the plant needs something you're not giving it? Is this one of the
paphs that need calcium in the mix? If this is the case the change of mix
would explain why it grew for a while and then started to fail. Check the
plant's parentage and see if it has calcelious (I can't spell) .....parents
that need calcium in their mix to enable them to take up nutrients.

Let us know what you find out.

Good Growing,
Gene






"germ" wrote in message
m...

I have a Paph. Transcolor that has not been growing well for a year
and a half. It was in a bark mix in a 5in plastic pot until 6 months
ago, repooted 6 months before that. I now have it in a coconut husk
mix in a 5 inch clear pot. The coconut mix is the one that I use for
all of my Paphs. ala Antec

The roots look good, they have grown since repotting. I tapped out
some of the mix and the roots are firm and fuzzy like they should be.
The three crowns of the plant have continued to grow, but they have
lost larger outer leaves in favor of smaller inner ones. The leaves
are waxy and small and light colored and they keep growing and the
outer ones keep falling!

This is a picture of the flowers and leaves of the second blooming
after I purchased it. (It was purchased in bloom, it bloomed again 6
months later, and then this blooming, its last in two years.)

http://members.verizon.net/~vze4xcmt...transcolor.jpg

I grew it in an east window indoors up until this fall. I tried
moving it under lights with the rest of my collection to see if that
would help, still no signs of improvement.

Thanks,
Jim





  #4   Report Post  
Old 31-01-2003, 10:04 PM
Gareth Wills
 
Posts: n/a
Default Languishing Paphiopedilum

Sorry to disagree, in part, Steve,but Fowlie is wrong. The only chemicals
(barring a few weirdos) that dissolve better in cooler temps than warm ones
are gases such as oxygen. Calcium compounds are notoriously insoluble except
in acids. Therefore acid water could cause a toxic buildup. Or using acidic
peat moss could have the same effect, but not in neutral coconut. I'd say
limestone marble chips would be great with coconut for the calceocolous
paphs (but I haven't tried it - yet. Good idea though.)
Gary

"Steve" wrote in message ...
Good thinking Gene, you could be right. Wildcatt lists Paph Transcolor
as 50% concolor, 25% rothschildianum, and 25% chamberlainianum.
Concolor is of course calcicolous and rothschildianum is not. I had to
look up the 3rd ancestor. I found this web site:
http://www.angelfire.com/or3/orchids...hlopetalum.htm which
contains this quote:

"Growing on limestone cliff faces near running creeks, and in water
seepage zones, it sought thick pads of humus and leaf detritus which had
accumulated against tree roots. While growing in limestone, Fowlie notes
they should not be cultivated on limestone chips, as the cooler water of
our temperate climates would allow greater dissolution of the limestone
particles, possibly furnishing toxic levels of calcium to the plants.
Naturally it receives bright but not direct sunlight."

I guess Transcolor is mostly calcicolous and should be supplemented with
lime in some form. I use a top dressing of crushed oyster shell, myself.

Steve in the Adirondacks of northern NY






Gene Schurg wrote:
Germ,

Interesting problem! You say that the roots are healthy and growing

which
is the first suspect in a mystery such as this.

5 inch pot sounds a bit large but you didn't state the leaf spread so I
can't say for sure. But since the roots are growing well I assume this

is
not the issue.

You mention the larger leaves are dropping and new smaller ones are
replacing them. I see this when a plant gets too much light and is
stressed. Doesn't sound like light is your issue since you moved the

plant
under lights and before that it was in an east window. Hmmmm (could it

be
the butler in the library with the candlestick?)

What a mystery....maybe it's the potting mix? no, you said you are

using it
for other paphs.

Maybe the plant needs something you're not giving it? Is this one of

the
paphs that need calcium in the mix? If this is the case the change of

mix
would explain why it grew for a while and then started to fail. Check

the
plant's parentage and see if it has calcelious (I can't spell)

......parents
that need calcium in their mix to enable them to take up nutrients.

Let us know what you find out.

Good Growing,
Gene






"germ" wrote in message
m...

I have a Paph. Transcolor that has not been growing well for a year
and a half. It was in a bark mix in a 5in plastic pot until 6 months
ago, repooted 6 months before that. I now have it in a coconut husk
mix in a 5 inch clear pot. The coconut mix is the one that I use for
all of my Paphs. ala Antec

The roots look good, they have grown since repotting. I tapped out
some of the mix and the roots are firm and fuzzy like they should be.
The three crowns of the plant have continued to grow, but they have
lost larger outer leaves in favor of smaller inner ones. The leaves
are waxy and small and light colored and they keep growing and the
outer ones keep falling!

This is a picture of the flowers and leaves of the second blooming
after I purchased it. (It was purchased in bloom, it bloomed again 6
months later, and then this blooming, its last in two years.)

http://members.verizon.net/~vze4xcmt...transcolor.jpg

I grew it in an east window indoors up until this fall. I tried
moving it under lights with the rest of my collection to see if that
would help, still no signs of improvement.

Thanks,
Jim







  #5   Report Post  
Old 31-01-2003, 11:07 PM
Ray @ First Rays Orchids
 
Posts: n/a
Default Languishing Paphiopedilum

Gary,

Are you sure about that? Limestone is calcium carbonate, and is quite
soluble in water. That's mostly what makes folks' water "hard."

If I remember my CRC Handbook lookups, calcium carbonate is more soluble in
cold than warm water. I could be wrong - I haven't looked it up in a long
time...

--

Ray Barkalow First Rays Orchids
http://www.firstrays.com
Secure Online Ordering & Lots of Free Info!


"Gareth Wills" wrote in message
...
Sorry to disagree, in part, Steve,but Fowlie is wrong. The only chemicals
(barring a few weirdos) that dissolve better in cooler temps than warm

ones
are gases such as oxygen. Calcium compounds are notoriously insoluble

except
in acids. Therefore acid water could cause a toxic buildup. Or using

acidic
peat moss could have the same effect, but not in neutral coconut. I'd say
limestone marble chips would be great with coconut for the calceocolous
paphs (but I haven't tried it - yet. Good idea though.)
Gary

"Steve" wrote in message

...
Good thinking Gene, you could be right. Wildcatt lists Paph Transcolor
as 50% concolor, 25% rothschildianum, and 25% chamberlainianum.
Concolor is of course calcicolous and rothschildianum is not. I had to
look up the 3rd ancestor. I found this web site:
http://www.angelfire.com/or3/orchids...hlopetalum.htm which
contains this quote:

"Growing on limestone cliff faces near running creeks, and in water
seepage zones, it sought thick pads of humus and leaf detritus which had
accumulated against tree roots. While growing in limestone, Fowlie notes
they should not be cultivated on limestone chips, as the cooler water of
our temperate climates would allow greater dissolution of the limestone
particles, possibly furnishing toxic levels of calcium to the plants.
Naturally it receives bright but not direct sunlight."

I guess Transcolor is mostly calcicolous and should be supplemented with
lime in some form. I use a top dressing of crushed oyster shell, myself.

Steve in the Adirondacks of northern NY






Gene Schurg wrote:
Germ,

Interesting problem! You say that the roots are healthy and growing

which
is the first suspect in a mystery such as this.

5 inch pot sounds a bit large but you didn't state the leaf spread so

I
can't say for sure. But since the roots are growing well I assume

this
is
not the issue.

You mention the larger leaves are dropping and new smaller ones are
replacing them. I see this when a plant gets too much light and is
stressed. Doesn't sound like light is your issue since you moved the

plant
under lights and before that it was in an east window. Hmmmm (could

it
be
the butler in the library with the candlestick?)

What a mystery....maybe it's the potting mix? no, you said you are

using it
for other paphs.

Maybe the plant needs something you're not giving it? Is this one of

the
paphs that need calcium in the mix? If this is the case the change of

mix
would explain why it grew for a while and then started to fail. Check

the
plant's parentage and see if it has calcelious (I can't spell)

.....parents
that need calcium in their mix to enable them to take up nutrients.

Let us know what you find out.

Good Growing,
Gene






"germ" wrote in message
m...

I have a Paph. Transcolor that has not been growing well for a year
and a half. It was in a bark mix in a 5in plastic pot until 6 months
ago, repooted 6 months before that. I now have it in a coconut husk
mix in a 5 inch clear pot. The coconut mix is the one that I use for
all of my Paphs. ala Antec

The roots look good, they have grown since repotting. I tapped out
some of the mix and the roots are firm and fuzzy like they should be.
The three crowns of the plant have continued to grow, but they have
lost larger outer leaves in favor of smaller inner ones. The leaves
are waxy and small and light colored and they keep growing and the
outer ones keep falling!

This is a picture of the flowers and leaves of the second blooming
after I purchased it. (It was purchased in bloom, it bloomed again 6
months later, and then this blooming, its last in two years.)

http://members.verizon.net/~vze4xcmt...transcolor.jpg

I grew it in an east window indoors up until this fall. I tried
moving it under lights with the rest of my collection to see if that
would help, still no signs of improvement.

Thanks,
Jim











  #6   Report Post  
Old 01-02-2003, 12:57 AM
Steve
 
Posts: n/a
Default Languishing Paphiopedilum



Gareth Wills wrote:
Sorry to disagree, in part, Steve,but Fowlie is wrong. The only chemicals
(barring a few weirdos) that dissolve better in cooler temps than warm ones
are gases such as oxygen. Calcium compounds are notoriously insoluble except
in acids. Therefore acid water could cause a toxic buildup. Or using acidic
peat moss could have the same effect, but not in neutral coconut. I'd say
limestone marble chips would be great with coconut for the calceocolous
paphs (but I haven't tried it - yet. Good idea though.)
Gary



Yeah, that sounded weird to me too. I didn't think about it too much and
just copied the entire paragraph. I should have just left that part out.

Steve

  #7   Report Post  
Old 01-02-2003, 02:35 AM
Eric Muehlbauer
 
Posts: n/a
Default Languishing Paphiopedilum

Yes, calcium carbonate, unlike most substances, tends to be more soluble
in cooler water. However, its not so soluble that cool water will
dissolve a toxic amount of calcium. I use oyster shell on calcium loving
paphs, even with my coconut chips. For some, like parvi's and brachy's,
I include large marble chunks at the bottom of the pot...hopefully
simulating a more natural situation where roots contact
limestone/marble/dolomite under the organic material..Take care, Eric
Muehlbauer...fanaticum opening while emersonii is taking its sweet time....

  #8   Report Post  
Old 01-02-2003, 03:57 AM
germ
 
Posts: n/a
Default Languishing Paphiopedilum

I realized that a concolor hybrid should have some lime in the mix. I
gave it as much crushed oyster shell as my malopoense and armeniacum.

I found this looking today:
http://www.ladyslipper.com/calsub.htm

I am going to repot it again. I will use marble chips in place of the
large alifor in the mix. I cannot think of anything else to do!

Thanks for the comments.
  #9   Report Post  
Old 01-02-2003, 04:10 AM
Aaron Hicks
 
Posts: n/a
Default Languishing Paphiopedilum

"Gareth Wills" spaketh thusly:

Sorry to disagree, in part, Steve,but Fowlie is wrong. The only chemicals
(barring a few weirdos) that dissolve better in cooler temps than warm
ones are gases such as oxygen. Calcium compounds are notoriously
insoluble except in acids.


Then, unfortunately for your system, you are going to have to lump
calcium carbonate in with the "few weirdos" as its solubility decreases as
temperature increases. I base my claims as regards to this paradox on
statements made in two separate copies of the CRC Handbook of Physics and
Chemistry, my attending graduate school in stable isotope geochemistry
(even if I wasn't all there at the time), and perhaps most importantly,
the laws of physics and chemistry.

Poor, neglected calcium carbonate, every caver's best friend. The
solubility of calcium carbonate is tied to the concentration of the
bicarbonate anion, which is present in solution in low concentrations
thanks to atmospheric carbon dioxide. An increase in the temperature
causes carbon dioxide to become less soluble in solution and, along with
it, the solubility of calcium carbonate also decreases. You may thank
LeChatelier's Principle for this (although, if you wish to thank me
instead, 20's and 50's are welcome- send them to your local high school
chemistry teacher). An excellent primer, if you're bored to death, is
found he

http://members.aol.com/profchm/comonion.html

Back to carbonate solubility!

Behold! The caver's formula:

CO2 + H20 -- H2CO3

Carbon dioxide plus water gives you carbonic acid.

Carbonic acid loses its first proton- a moment we should all pause
to reflect upon, but not he privately. When you're done, come back;
we'll still be here. Really.

Pure water has pH 7.0; let it sit around and pretend it's Perrier,
next thing you know, those water molecules are all over the carbon dioxide
like a dog on a Dreamsicle, and the pH plunges to 5.6 with atmospheric
concentrations of carbon dioxide (about 380 ppm or, under new Bush
administration projections, 2,280 ppm by 2040). Higher concentrations of
atmospheric carbon dioxide drops the pH even more, and heaven only knows
what this means for the planet's coral reefs; the ocean has the bajeezus
buffered out of it, but when you're talking about something that massive,
anything goes. Maybe upping the temperature will throw the equilibrium in
the opposite direction. :-P At least the "coral calcium" crap at the
health food store will be cheaper. Try not to let too much too much
strontium build up in your system. "Tums" are made with synthetic calcium
carbonate; corals accumulate Sr, as well as lead and other heavy nasties
at levels that you do not want to be ingesting.

On the bright side, more CO2 = more caves, the very thought of
which makes us troglodytes revel in ecstasy. But the really big caves are
formed with sulfuric acid, which is probably biogeochemical in origin.
That's another lecture. Bring a "blue book," there'll be a short quiz
afterwards.

Cheers,

-AJHicks
Chandler, AZ




  #10   Report Post  
Old 02-02-2003, 12:24 AM
Gareth Wills
 
Posts: n/a
Default Languishing Paphiopedilum

Ok Aaron, the buffering ability of the bicarbonate ion is well known. The
solubility of CaCO3 decreases with increased temps above normal. This does
not mean that the solubility increases with decreasing temps below ambient
(look up buffers). In cooler temps, CaCO3 precipitates since the solubility
coefficient is so low. The major factor here is the acidity which negates
LeChatelier and the above discussion since CO2 is no longer one of the major
players. Acetates, humic acids, chlorides, and nitrates of calcium are
soluble and plentiful in peat moss mixes which overwhelms the buffering
capacity of the bicarbonate ion, which was the point. I am a high school
chemistry teacher of 34 years and put the 50's in my pocket, thank you. But
as any other high school teacher knows, they leak back into the classroom
anyway.
Gary
"Aaron Hicks" wrote in message
...
"Gareth Wills" spaketh thusly:

Sorry to disagree, in part, Steve,but Fowlie is wrong. The only chemicals
(barring a few weirdos) that dissolve better in cooler temps than warm
ones are gases such as oxygen. Calcium compounds are notoriously
insoluble except in acids.


Then, unfortunately for your system, you are going to have to lump
calcium carbonate in with the "few weirdos" as its solubility decreases as
temperature increases. I base my claims as regards to this paradox on
statements made in two separate copies of the CRC Handbook of Physics and
Chemistry, my attending graduate school in stable isotope geochemistry
(even if I wasn't all there at the time), and perhaps most importantly,
the laws of physics and chemistry.

Poor, neglected calcium carbonate, every caver's best friend. The
solubility of calcium carbonate is tied to the concentration of the
bicarbonate anion, which is present in solution in low concentrations
thanks to atmospheric carbon dioxide. An increase in the temperature
causes carbon dioxide to become less soluble in solution and, along with
it, the solubility of calcium carbonate also decreases. You may thank
LeChatelier's Principle for this (although, if you wish to thank me
instead, 20's and 50's are welcome- send them to your local high school
chemistry teacher). An excellent primer, if you're bored to death, is
found he

http://members.aol.com/profchm/comonion.html

Back to carbonate solubility!

Behold! The caver's formula:

CO2 + H20 -- H2CO3

Carbon dioxide plus water gives you carbonic acid.

Carbonic acid loses its first proton- a moment we should all pause
to reflect upon, but not he privately. When you're done, come back;
we'll still be here. Really.

Pure water has pH 7.0; let it sit around and pretend it's Perrier,
next thing you know, those water molecules are all over the carbon dioxide
like a dog on a Dreamsicle, and the pH plunges to 5.6 with atmospheric
concentrations of carbon dioxide (about 380 ppm or, under new Bush
administration projections, 2,280 ppm by 2040). Higher concentrations of
atmospheric carbon dioxide drops the pH even more, and heaven only knows
what this means for the planet's coral reefs; the ocean has the bajeezus
buffered out of it, but when you're talking about something that massive,
anything goes. Maybe upping the temperature will throw the equilibrium in
the opposite direction. :-P At least the "coral calcium" crap at the
health food store will be cheaper. Try not to let too much too much
strontium build up in your system. "Tums" are made with synthetic calcium
carbonate; corals accumulate Sr, as well as lead and other heavy nasties
at levels that you do not want to be ingesting.

On the bright side, more CO2 = more caves, the very thought of
which makes us troglodytes revel in ecstasy. But the really big caves are
formed with sulfuric acid, which is probably biogeochemical in origin.
That's another lecture. Bring a "blue book," there'll be a short quiz
afterwards.

Cheers,

-AJHicks
Chandler, AZ








  #11   Report Post  
Old 02-02-2003, 05:39 AM
Aaron Hicks
 
Posts: n/a
Default Languishing Paphiopedilum


The skies did open, and through the rent the mighty voice of
"Gareth Wills" spaketh thusly:

Ok Aaron, the buffering ability of the bicarbonate ion is well known. The
solubility of CaCO3 decreases with increased temps above normal. This
does not mean that the solubility increases with decreasing temps below
ambient (look up buffers).


Check your CRC. The solubility of calcium carbonate INCREASES
dramatically below ambient. In the event you have misplaced it, I refer
you to a chart from Faure's "Principles and Applications of Inorganic
Geochemistry," page 223, posted for your viewing pleasure at:

http://members.cox.net/ahicks51/calciumcarbonate.jpg

Two partial pressures of carbon dioxide are given; the upper curve
is closest to actual. As can be seen, the solubility of calcium carbonate
(as measured by the [Ca+2], coming from dissolved calcite) increases
dramatically as temperature drops, particularly *below* 20 C. Solubility
does, in fact, increase with decreasing temperature.

"The solubility of calcite [calcium carbonate, limestone] is also
affected by the temperature because of changes in the numerical values of
all the equilibrium constants. Garrels and Christ (1965) compiled the set
of values of the relevant equilibrium constants between 0 and 50 degrees
C that is listed in Table 12.6 [not shown here]. We see by inspection that
the dissociation constants of carbonic acid _increase_ with increasing
temperature, whereas the solubility product constants of calcite and CO2
_decrease_. As a result, the solubility of calcite in pure water in
equilibrium with CO2 of the atmosphere actually _decreases_ with
increasing temperature, as shown in Figure 12.4 [as above]. For example, a
saturated solution of calcite in equilibrium with CO2 at 3x10^-3 atm
contains about 75 mg/L of Ca+2, at 5 degrees C but only 40 mg/L at 30
degrees C."

_Emphasis_ is that of the author. [This stuff] is mine, as are
typos.

In cooler temps, CaCO3 precipitates since the solubility coefficient is
so low.


No. This is why hot water heaters fill with calcium carbonate
precipitate in regions with hard water. Cold water in, hard water out,
leave the calcium carbonate behind. Wait five years until it's full of
"sand."

The major factor here is the acidity which negates LeChatelier and the
above discussion since CO2 is no longer one of the major players.
Acetates, humic acids, chlorides, and nitrates of calcium are soluble and
plentiful in peat moss mixes which overwhelms the buffering capacity of
the bicarbonate ion, which was the point.


Ah! A correct statement. I do not dispute this. However, stating
that Fowlie is wrong because the solubility of calcium carbonate is
proportional to temperature is wrong, and I will take issue with this. I
will happily admit that the other components of the system, when in
sufficiently high concentrations, will quickly overwhelm the system (but
not "negate" LeChatelier- one does not negate laws of chemistry and
physics without congressional approval, or at least help from the
president of the American Chemical Association).

One last factor of potential interest is the ability of roots to
remove carbon dioxide from their environment, fostering the precipitation
of calcium carbonate and other minerals within proximity of their roots.
When fossilized, they form "rhizocretions." Do a Google search. They're
cool. These trace fossils may also occur after plant death, so they're not
an absolute indication of this sort of activity on the part of the plant.


-AJHicks
Chandler, AZ






  #12   Report Post  
Old 02-02-2003, 11:37 AM
Gareth Wills
 
Posts: n/a
Default Languishing Paphiopedilum

OK, AH, you did your homework. Thanks for the corrections to my incomplete
and impulsive response. I spoke too quickly in generalities when I was
meaning to apply it to the situation of acid soil and paphs and not systems
where the pH is neutral or above or within the effective buffering range of
bicarbonate. Acid solutions are not covered in your arguements. My
references are not here with me, but I believe a warm acid will dissolve
carbonates better than a cold one. So my terms of "wrong" and "negate" were
inappropriate. "Not fully applicable to the situation" would have been
better. Let's both stick to chemistry applicable to this board and its
purpose - to grow better orchids.
Gary
"Aaron Hicks" wrote in message
...

The skies did open, and through the rent the mighty voice of
"Gareth Wills" spaketh thusly:

Ok Aaron, the buffering ability of the bicarbonate ion is well known. The
solubility of CaCO3 decreases with increased temps above normal. This
does not mean that the solubility increases with decreasing temps below
ambient (look up buffers).


Check your CRC. The solubility of calcium carbonate INCREASES
dramatically below ambient. In the event you have misplaced it, I refer
you to a chart from Faure's "Principles and Applications of Inorganic
Geochemistry," page 223, posted for your viewing pleasure at:

http://members.cox.net/ahicks51/calciumcarbonate.jpg

Two partial pressures of carbon dioxide are given; the upper curve
is closest to actual. As can be seen, the solubility of calcium carbonate
(as measured by the [Ca+2], coming from dissolved calcite) increases
dramatically as temperature drops, particularly *below* 20 C. Solubility
does, in fact, increase with decreasing temperature.

"The solubility of calcite [calcium carbonate, limestone] is also
affected by the temperature because of changes in the numerical values of
all the equilibrium constants. Garrels and Christ (1965) compiled the set
of values of the relevant equilibrium constants between 0 and 50 degrees
C that is listed in Table 12.6 [not shown here]. We see by inspection that
the dissociation constants of carbonic acid _increase_ with increasing
temperature, whereas the solubility product constants of calcite and CO2
_decrease_. As a result, the solubility of calcite in pure water in
equilibrium with CO2 of the atmosphere actually _decreases_ with
increasing temperature, as shown in Figure 12.4 [as above]. For example, a
saturated solution of calcite in equilibrium with CO2 at 3x10^-3 atm
contains about 75 mg/L of Ca+2, at 5 degrees C but only 40 mg/L at 30
degrees C."

_Emphasis_ is that of the author. [This stuff] is mine, as are
typos.

In cooler temps, CaCO3 precipitates since the solubility coefficient is
so low.


No. This is why hot water heaters fill with calcium carbonate
precipitate in regions with hard water. Cold water in, hard water out,
leave the calcium carbonate behind. Wait five years until it's full of
"sand."

The major factor here is the acidity which negates LeChatelier and the
above discussion since CO2 is no longer one of the major players.
Acetates, humic acids, chlorides, and nitrates of calcium are soluble and
plentiful in peat moss mixes which overwhelms the buffering capacity of
the bicarbonate ion, which was the point.


Ah! A correct statement. I do not dispute this. However, stating
that Fowlie is wrong because the solubility of calcium carbonate is
proportional to temperature is wrong, and I will take issue with this. I
will happily admit that the other components of the system, when in
sufficiently high concentrations, will quickly overwhelm the system (but
not "negate" LeChatelier- one does not negate laws of chemistry and
physics without congressional approval, or at least help from the
president of the American Chemical Association).

One last factor of potential interest is the ability of roots to
remove carbon dioxide from their environment, fostering the precipitation
of calcium carbonate and other minerals within proximity of their roots.
When fossilized, they form "rhizocretions." Do a Google search. They're
cool. These trace fossils may also occur after plant death, so they're not
an absolute indication of this sort of activity on the part of the plant.


-AJHicks
Chandler, AZ








  #13   Report Post  
Old 03-02-2003, 02:18 PM
germ
 
Posts: n/a
Default Languishing Paphiopedilum

I got around to actually repotting it yesterday. The roots were very
good and they had dozens of nice growing white tips. As for the leaf
span you asked for. The plant was once over a 12-inch leaf span, now
it is 6 inches! I put marble in the bottom of the pot. If it wants
calcium I guess it can towards the rocks. Right?

It is odd I know! I am going to take it to the Paph forum in DC later
this month. Someone there will likely see immediately what is wrong.

Thanks
Jim

PS I also repotted a Paph Susan Booth x bellatulum, kind of similar
breeding, it was pot bound in the same mix Transcolor, it grew next to
Transcolor, and was last repotted with Transcolor, but it looks great
unlike Transcolor.


"Gene Schurg" wrote in message link.net...
Germ,

Interesting problem! You say that the roots are healthy and growing which
is the first suspect in a mystery such as this.

5 inch pot sounds a bit large but you didn't state the leaf spread so I
can't say for sure. But since the roots are growing well I assume this is
not the issue.

You mention the larger leaves are dropping and new smaller ones are
replacing them. I see this when a plant gets too much light and is
stressed. Doesn't sound like light is your issue since you moved the plant
under lights and before that it was in an east window. Hmmmm (could it be
the butler in the library with the candlestick?)

What a mystery....maybe it's the potting mix? no, you said you are using it
for other paphs.

Maybe the plant needs something you're not giving it? Is this one of the
paphs that need calcium in the mix? If this is the case the change of mix
would explain why it grew for a while and then started to fail. Check the
plant's parentage and see if it has calcelious (I can't spell) .....parents
that need calcium in their mix to enable them to take up nutrients.

Let us know what you find out.

Good Growing,
Gene



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