Phrag kovachii culture!

[gonewild]

Check this out Bjorn
http://www.spectrumanalytic.com/support/library/ff/Cl_Basics.htm

Basically infers antagonism amongst anions (Nitrate, Phosphate, Chloride, Sulfate)

And note the picture of the chloride deficient plant.

This could go back to the potential for sclerosis when calcium nitrate is used in RO as the sole source of N, and Ca, and a better reason why epsom salts (magnesium SULFATE) greens things up in the presence of excess nitrate.

That makes one think then adding a little sodium chloride to ro water to get the chloride might be a good idea. But with 30ppm of chlorides you get something like 20ppm sodium. What good or bad effect does sodium have? More bad than good and a high risk....
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC139373/

 

[Rick]

That makes one think then adding a little sodium chloride to ro water to get the chloride might be a good idea. But with 30ppm of chlorides you get something like 20ppm sodium. What good or bad effect does sodium have? More bad than good and a high risk....
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC139373/

Sodium is pretty benign (its a lot more common and less bioreactive than potassium) and we used to throw 100ppm of K on our plants all the timeoke:

However, we could work it from the opposite direction (use proportionately less nitrate), and/or mix and match other anions (like more sulfate from gypsum or Epsom salt, or phosphate from bone meal i.e. calcium phosphate).

I generally don't recommend adding more of anything just to counteract too much of something else. Go for eco-relevance and get rid of the excess before adding more crap to the pile.

 

[gonewild]

Some old habits die hard, I won't be adding any sodium and I will continue to remove it whenever possible. But a lot of potassium is no longer welcome at my house, it was an old habit.

 

[Stone]

I made a table of available leaf tissue data since Stone brought up Xavier's 2008 post with some wild paph data. Note that the potassium discussions didn't start till 2010 - 20111. This table includes leaf tissue data on in situ PK and the Paph leaf tissue sufficiency standards from University of Hawaii (which is what you get if you "pile on" nitrate and potassium via balanced fertilizer application.



Note that wild plants should be dead from N and K deficiency compared to what U of H considers normal tissue concentrations of these nutrients.

I'm not sure what your trying to say here. From this data, kovachii seems to either have low K or high soluble Ca available or both. However, remember that K is extremely mobile (probably the most) Ca is extremely immobile. Add lots of rainfall/water into that habitat, and you would expect these kind of figures. No doubt besseae would be similar even though it comes from granite.

The ''chlorotic'' mastersianum has less Ca AND less K than the ''wild'' masterianum. I presume this would be caused by higher ammonuim supplementaion given in cultivation. Probably a good case for bringing in more nitrates. In this case though K obviously is not causing a problem lowering Ca and Mg levels. More likely NH4 is.

With all the plants (cultivated and wild and apart from kovachii), the difference in the concentrations of K and Ca in the leaf tissue is statistically insignificant. More proof that there is no need to drastically lower K to keep Ca levels where you want them. More proof that in the habitat (apart from kovachii MAYBE), the orchids are getting similar N/K ratios that we (I) give them arriving at their roots over a year.

If you want to increase the Ca concentration in the leaf, increase your nitrate/ammonium ratio to 3 to1 (what I'm doing). Of course this will also increase K and Mg levels in the leaf as well. Which is absolutlely fine with me.

None of this data shows me that varying Ca leaf concentrations makes the slightest bit of difference in plant performace.
And I can only judge this by the fact that although my orchids get plenty of potassium I see no evidence of sudden death or lack of root growth or erwinia or whatever.
Since I have made my NO3/NH4 ratio 3 or 4 to 1 I have seen improved growth size and leaf colour (less chlorosis) in the older leaves. I put this down to better Mg absorption. But the K and Ca would also be up.

 

[Stone]

Keep in mind that the K ranges are inverse to Ca and Mg when you look at individual plant data (i.e the higher the K the lower the Ca/Mg).

You cannot just say this without the NH4 factor. The chlorotic mastersianum has lower K than the wild one but does not have higher Ca and Mg than the wild one.

Another point of note is the effect of ammonium as opposed to nitrate. Once again there are references in the Cornell work and others that ammonium (which is a potent cation) is antagonistic to K, Ca, Mg. It seems to be the only cation that effectively blocks K into plants. Nitrate (an anion) does not do this, so as Mike pointed out that Roth's (Xavier's) nitrogen source is ammonium dependent, the difference in leaf tissue NPKCaMg of his cultivated paphs is most likely different than the UH plants (or MSU plants) due to the use of ammonium /urea rather than some unknown natural self K/Ca regulating feature of the plants.

Exactly. So why is K the problem? Too much ammonium is the ''problem'' here. There is no evidence that high tissue K causes a problem if it is balanced by high tissue Ca and Mg. (which you get if you lower NH4)

 

[gonewild]

I'm not sure what your trying to say here. From this data, kovachii seems to either have low K or high soluble Ca available or both. However, remember that K is extremely mobile (probably the most) Ca is extremely immobile. Add lots of rainfall/water into that habitat, and you would expect these kind of figures. No doubt besseae would be similar even though it comes from granite.

besseae does not come from granite. It comes from red and white sandstone. I'm not sure if any Peruvian Phrags grow on granite.

 

[Stone]

besseae does not come from granite. It comes from red and white sandstone. I'm not sure if any Peruvian Phrags grow on granite.

My mistake

 

[Rick]

Exactly. So why is K the problem? Too much ammonium is the ''problem'' here. There is no evidence that high tissue K causes a problem if it is balanced by high tissue Ca and Mg. (which you get if you lower NH4)

Well you haven't figured out why my results (and many others) improved dramatically after reducing the K in our feed.

And you haven't demonstrated that you can "balance" high tissue K with additional application of Ca and Mg (actually you supplied the Cornell paper years ago that showed that high soluble Ca could not prevent or balance increasing tissue K when applied at high concentrations in an all nitrate based form of N).

And you haven't demonstrated that high K is necessary, or that K deficiency occurs when applied at a fraction of recommended via the "weakly weekly" standard. (I've been doing it for almost 4 years now and still waiting for the big crash).

You also haven't demonstrated that for PK (the original species in question of this thread) that applying NPK at high rates produces a healthier plant than those poor impoverished plants in the wild, or that it would be a disservice to the plant to supply mineral nutrition at eco-relevant levels.

 

[Rick]

Since this is a thread on PK culture I wasn't going to bring this up til Mike posted Xavier's 2008 thread.


To Quote:
"I had plants cultivated for a while, and "new" plants for mastersianum. The latter invariable are much healthier than the former ones as a rule. Mastersianum in the wild has very dark green, shiny leaves, and is a very fast grower. In cultivation the plants tends to become more on the yellowish side, and most die after some years of being chlorotic and necrotic. Only a very few mastersianum in the world survive more than 5 years in cultivation, one has to be realistic..."

My mastersianum are thriving almost 6 years out of flask, and this one, and one of its sibs, are starting to spike again (even after 3 years of an imbalanced and deficient diet).
http://www.slippertalk.com/forum/showthread.php?t=33806&highlight=mastersianum

In 2008 Xavier had similar comments on Paph emersonii, But here's my plant bigger than ever in 2015, even after 3 years of an imbalanced and deficient diet.
http://www.slippertalk.com/forum/showthread.php?t=36652&highlight=emersonii

 

[Stone]

Well you haven't figured out why my results (and many others) improved dramatically after reducing the K in our feed.

That's not my job and I couldn't do that from here anyway. But you have changed other things, lower EC, more water, baskets. Any of these things could potentially improve growth.
But you also have not demonstrated that your drastically improved growth is any better than those of us who have not reduced K. In other words has the K reduction improved growth beyond all others efforts. If not, I don't see the evidence. (if that makes sense)

And you haven't demonstrated that you can "balance" high tissue K with additional application of Ca and Mg

Well that depends on what you consider to be high tissue K. If it is roughly equal to the Ca in the leaf, I would consider that fairly normal. I would also call that fairly balanced from all the leaf tissue data I have seen. Sometimes higher sometimes lower..So in that instance there is no need to increase Ca application. If there is a defecit in Ca in the leaf, (much less than the above type of average) it is not because of K antagonism (or not only) in most cases. most likely a shortage of Ca (unlikely), very low pH for a particular species, and/or too much ammonium. K also plays a part.

(actually you supplied the Cornell paper years ago that showed that high soluble Ca could not prevent or balance increasing tissue K when applied at high concentrations in an all nitrate based form of N).

True but from memory, they used a very high concentration of K and did not report reduced growth anyway, but I will need to look at that again

And you haven't demonstrated that high K is necessary

,

I never said it was necessary and that was never really an issue. The issue was/is whether it causes all the problems you claim. I think I have demonstrated that to myself at least, that it doesn't.

or that K deficiency occurs when applied at a fraction of recommended via the "weakly weekly" standard.

Well that is another matter. Low K is implicated in leaf tip die back in Cymbidium here (along with inadequate water)

K supplied at 50% of N seems to be enough in the dendrobium and phal studies I have read. That is just from memory though and I seem to remember reduced growth response when less than that. But I will check that.

You also haven't demonstrated that for PK (the original species in question of this thread) that applying NPK at high rates produces a healthier plant than those poor impoverished plants in the wild, or that it would be a disservice to the plant to supply mineral nutrition at eco-relevant levels.

I would not try to demonstrate that because I don't advocate feeding NPK at high rates to this species

 

[Stone]

Since this is a thread on PK culture I wasn't going to bring this up til Mike posted Xavier's 2008 thread.


To Quote:
"I had plants cultivated for a while, and "new" plants for mastersianum. The latter invariable are much healthier than the former ones as a rule. Mastersianum in the wild has very dark green, shiny leaves, and is a very fast grower. In cultivation the plants tends to become more on the yellowish side, and most die after some years of being chlorotic and necrotic. Only a very few mastersianum in the world survive more than 5 years in cultivation, one has to be realistic..."

My mastersianum are thriving almost 6 years out of flask, and this one, and one of its sibs, are starting to spike again (even after 3 years of an imbalanced and deficient diet).
http://www.slippertalk.com/forum/showthread.php?t=33806&highlight=mastersianum

In 2008 Xavier had similar comments on Paph emersonii, But here's my plant bigger than ever in 2015, even after 3 years of an imbalanced and deficient diet.
http://www.slippertalk.com/forum/showthread.php?t=36652&highlight=emersonii

Love those plants. There is no denying that you have their culture down and that they are doing well on your regime, but I can show you plenty of orchids which are considered difficult to grow as well (I have those paph species but they are very small) and they do not get your low K regime at all. So what does that tell us?