'What Orchids Eat', importance of calcium

[King_of_orchid_growing:)]

Originally Posted by Ray

King,

I think the term "toxicity" may be getting a bit over-played or over-interpreted in this case. (David will likely accuse me of changing the subject again, but...) while in the mollusks, the excessive potassium may very well be truly toxic, in the U of MD study with people, the symptoms were of a far lesser degree, but still negative.

One of Rick Lockwood's considerations early in his raising of the potential K issue, was the long-term decline of plants, or the fact that some observe that plants do great for years, then just flat crap out. He theorized that it MIGHT have something to do with potassium buildup. That will not be known definitively for a long time, and I'm glad to be part of the group that is open-minded enough to participate in the experiment. I have tried to explain why I have some "buy-in" to the concept, but others apparently feel its appropriate to dismiss that.

I will state clearly that I do not think the chemistry of tissue samples necessarily reflects the chemical requirements of the living creature analyzed. It would not surprise me, however, if the tissue sample was more indicative of the chemistry of the environment in which the creature lived.

If the former was absolutely true, one might conclude that people in the US need high levels of fats and sugars in their diet to be healthy.

Plants are extremely - although not entirely - passive in their uptake of chemicals. If that was not true, then we would not have any availability of systemic pesticides that are poured in the soil and found in the leaf tissue. That, alone, supports that what's in them may not be a good indicator of what they require - I have seen no literature suggesting that acephate- or imidicloprid metabolites are required nutrients.

If you talk to folks with advanced degrees in plant physiology and nutrition, you will get the admission that "nobody really knows" what's going on in this field. There is only experimentation to rely on, and even those results are open to interpretation. The myth that high phosphorus promotes blooming in an otherwise healthy plant is a prime example. And despite David's disregard of the fact, there is very little research on orchids (although it is growing), and if you read some of those that are out there, we learn there is a substantial difference between the physiologies of terrestrial and epiphytic plants.

I don't know if the same is true among growers of other plants, but it is amazing to me the vehemence with which folks argue about stuff in the orchid community. It is especially interesting and strong with fertilizers, which none of us knows - for a fact - "crap" about, yet folks freely attack opinions.


Ray Barkalow

The "crapping out" of orchids is not so simple as being due to one source...it could be due to a number of things.

For example, I believe I finally found out why Phalaenopsis appendiculata seems to grow well for 1 - 2 years and then crashes. I think it is not because of excessive K+. Rather, I believe that it is because this orchid is a nutrient and water hog in general. It is ridiculous how much this orchid appears to need in terms of nutrients. You would've thought that this little guy was a full sized Vanda! Most of these are most likely undernourished! I currently have another individual of this species, and I have finally gotten a new leaf that is closer to what it should really be in size!!! Apparently, in the past, I was wrong about how small Phal appendiculata really was. It is not the smallest Phalaenopsis within the genus, the smallest species of Phal is Phal gibbosa. Phal appendiculata is about 5 times larger than Phal gibbosa. I'm hypothesizing that most of the Phal appendiculata on the market are grossly undernourished, hence why they always present themselves as being just as small or a tiny bit smaller than Phal gibbosa.

Now, this is one example...

Here's yet another point-

Another group of orchids that seems to "crap out" a lot are those in the genus Disa. But I venture to believe this is in relation to them being nutrient hogs as well. In this instance, I believe that they are starving for K+. It is a shame that nobody has information about whether or not they are dying prematurely from starvation or not, but it seems to make some sense, since it has been a long time staple to advise people to reduce the concentration of fertilizer provided when growing this group of orchids, and these are by far some of the fastest growing orchids in existence! They grow almost just as fast as grass!!! I'd like to do tissue samples of these one day to see exactly what is going on with these orchids. Another possibility for Disas "crapping out" is possibly due to root rot, because people have a hard time figuring out the balance of water to air to provide the roots.

However...

If you guys are willing to experiment with the idea of possible long term K+ buildup being detrimental to long term orchid health, I'm not going to stop you guys, but you guys need to set up stringent controls for this. You guys can't experiment with any old orchid of any age, you must control it so you're dealing with orchids of roughly the same age. Preferably seedlings from the same batch of sowings. You also have to do it with one species or hybrid per experiment, that's it. There's no mixing or matching here. There's no room for that. Even the nutrient supplementation have to be controlled strictly. Aside from this, I don't know how you want to set up the controls for the K+, but this is a good spring point. I'll even add that this may even take several years to get any kind of reliable data. If you're up to it, then go for it. I'd like to see the hard data concerning this matter.

But in terms of the biology of a plant cell, I think I have some access to some articles that may point to the fact that I'm not 100% wrong on this. Plants do seem to have controls for ionic movement in and out of their cells. Again, because I'm not schooled in it, I can't say much other than what I can pull up on the internet.

Here is an article concerning K+ pumps in higher plants:

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Here's one on Ca2+ regulation:

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This one talks about a group of pumps called "electrogenic pumps":

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Yet another great article complete with diagrams, that distinctly provides evidence that ionic exchanges in plants are not just passive:

Energization of Plant Cell Membranes by H+-Pumping ATPases: Regulation and Biosynthesis

When you're talking about plants with foreign substances found inside their tissues, you have to take into consideration how large or how small that molecule is, and how it is getting into the plant. Is the foreign substance inside the cell or outside the cell? Is it binding to receptors? Is there an element associated with that molecule that the plant naturally would have an affinity for? Is it getting through via ionic pumps or ionic channels? Idk.

Just sayin'.

---------- Post added at 08:41 AM ---------- Previous post was at 08:19 AM ----------

Btw, disregard what the links say about the error message. There is no error, the links work fine.

[DavidCampen]

Originally Posted by Ray

David,

Nowhere in any of my posts have I "changed the subject" when responding.

You say that, yet here you are changing the subject once again.

Originally Posted by Ray

I get the impression that you firmly believe that whatever you have already learned or read is gospel, and not ever to be challenged.

So instead of changing the subject, challenge my assertion that you are wrong when you say that potassium binds more strongly to potting media than calcium or magnesium. Or challenge my statement that you are wrong when you say that orchids grow in a potassium deficient environment.

I also find it humorous, yet sad, that you tried these same arguments over at Slippertalk, did not gain a strong following, so abandoned that, choosing to raise the same arguments here.

Oh, lots of people at slipper talk don't accept this absurd potassium toxicity thesis that you keep promoting.

Originally Posted by Ray

I don't think any of your arguments are any stronger than anyone else's, or than they were there.

At least I don't keep mistating facts like you do.

Originally Posted by Ray

You are entitled to your own understandings and opinions, and I don't believe I-, or anyone else, has stated they were wrong.

I am stating that you and Lockwood are wrong about a number of material facts.

Originally Posted by Ray

At least have the decency to allow others to express theirs without a "Jane, you ignorant slut" attitude.

I have never called anyone names. Correcting your erroneous statements is not calling you a "slut". In fact, by accusing me of calling you a "slut" you are the one mounting a personal attack. Oh, and the "humorous yet sad" comment you made about me; another personal attack. Please stop making personal attacks and stick to facts and science.

Originally Posted by Ray

Enough, already.

Yes, please stop promoting your K-lite. Stop running the advertisement in Orchids claiming that there is science behind the k-lite formulation.

[tucker85]

Please, please let's be respectful of each other and keep these discussions civil.

[james mickelso]

Phew!!! I'm exhausted.

---------- Post added at 12:15 PM ---------- Previous post was at 12:04 PM ----------

And being a Neanderthal I just look at how well growers have done with flowering their orchids through the years and these finite discussions don't seem to grow orchids any better. Miniscule improvements are not worth the headaches. Just my troglodyte mentality I guess. A distilled argument with a timer would suffice. Just sayin.

[isurus79]

Originally Posted by DavidCampen

Yes, please stop promoting your K-lite. Stop running the advertisement in Orchids claiming that there is science behind the k-lite formulation.

Wow, this took a weird turn. David, you went from just being rude to straight up crazy. You now have zero credibility as far as I'm concerned.

[No-Pro-mwa]

What fun, you see people don't only fight over dog discussions they also fight over orchids.... who knew.

[Leafmite]

I just read a great article on plant nutrition...wish I had bookmarked it. It basically agreed with you, Ray. Potassium tends to be retained in media and builds up, then is more easily absorbed by the plant. A little goes a long way. The other nutrients tend to wash out more easily.
I add calcium, too, and find my plants do much better (except the cinnamon tree needed pH lowered). Phosperous is the difficult one for me as I am not certain what product has it readily available (bone meal is a slow release-deal).

---------- Post added at 05:15 PM ---------- Previous post was at 05:02 PM ----------

Perhaps the reason people have different experiences with different fertilizers is because:
1) different orchids, like many plants, are adapted to different environments and need different nutrients
2) different mediums retain nutients differently
3) plants behave differently in various environments.
I do grow a variety of plants and I have many different fertilizers. Pond plants get one, fruit trees get another, the peach needs blood and bone meal, the blueberries need Ironite, the citrus gets a special formula, I have hollytone and plant tone, Epsom salts, miracle grow, an MSU formula, and some other orchid stuff, plus oyster shell (and other calcium stuff). Yeah, it is great fun.

[Fabian24]

I don't really see the point of the discussion.


If somebody wants to starve his orchids of potassium, let him do it. Orchids, as most plants, can translocate K from older leaves to new ones. So he won't notice any symptoms for some time, and then the plants will weaken and die.

There are lots of scientific publications on orchid nutrition, and all of them report the same symptoms of lack of potassium.
Just to quote some paragraphs of a relatively new one:

At low K concentrations (50 and 100 mg_L–1 K), although no statistical comparison between the two media was attempted, it was apparent that plants in the bark mix flowered earlier than those in moss (Fig. 2A). Flower count (Fig. 2B) and flower diameter (Fig. 2C) on plants in both media increased with increasing K concentration, reaching their peaks at 300 mg_L–1 K in the bark mix and 400 mg_L–1 K in moss.
......
The length of the flower stem (inflorescence), either from the base to the first flowering node (Fig. 2D) or from the first flower to the tip (Fig. 2E), internodal length between the first two flowers (Fig. 2F), and flower stem diameter (Fig. 3) all increased with increasing K concentrations, reaching their peaks at 400 mg_L–1 K, regardless of the medium they were planted in.
......
Symptoms of severe K deficiency included yellowing, rusty or bronze patches, and necrosis (Fig. 4). This leaf yellowing and necrosis became more severe and leaves started to die acropetally as the flower stem continued to develop and particularly after anthesis. All plants grown in the bark mix and lacking K were dead by the end of May.
.....
In Phalaenopsis, both the length and the diameter of the flower stem increased with K concentration, improving structural support of the flowers. Increasing K concentration resulted in larger flowers in both Odontioda and Phalaenopsis.
....
When grown in a bark mix, 50 or 100 mg_L–1 K resulted in vegetative plants that appear healthy but developed some degrees of leaf yellowing or leaf abscission during flowering. Although applying 200 mg_L–1 K completely eliminated K deficiency symptoms and resulted in good growth and flowering in this study, to obtain top-quality Phalaenopsis with the greatest leaf length, highest flower count, largest flowers, and longest inflorescences, it is recommended that 300 mg_L–1 K be applied regardless of the medium.

Yin-Tung Wang, Potassium Nutrition Affects Phalaenopsis Growth and Flowering, HORTSCIENCE 42(7):1563–1567. (2007).

[King_of_orchid_growing:)]

Originally Posted by james mickelso

Phew!!! I'm exhausted.

---------- Post added at 12:15 PM ---------- Previous post was at 12:04 PM ----------

And being a Neanderthal I just look at how well growers have done with flowering their orchids through the years and these finite discussions don't seem to grow orchids any better. Miniscule improvements are not worth the headaches. Just my troglodyte mentality I guess. A distilled argument with a timer would suffice. Just sayin.

Yes! I whole heartedly agree, (not with the Neanderthal or the troglodyte parts, but I agree with the rest of it)! That was what I said in the beginning!!!

The way that fertilizers are formulated in addition to other factors, (such as plant physiology), there seems to be no real concern for K+ toxicity.

People have had long term success with orchids without worrying about K+ toxicity at all, and I am one of them!

I have orchids that are close to a decade old and I have very few problems with them. And I don't worry about K+ toxicity in the least bit.

Originally Posted by Leafmite

I just read a great article on plant nutrition...wish I had bookmarked it. It basically agreed with you, Ray. Potassium tends to be retained in media and builds up, then is more easily absorbed by the plant. A little goes a long way. The other nutrients tend to wash out more easily.
I add calcium, too, and find my plants do much better (except the cinnamon tree needed pH lowered). Phosperous is the difficult one for me as I am not certain what product has it readily available (bone meal is a slow release-deal).

---------- Post added at 05:15 PM ---------- Previous post was at 05:02 PM ----------

Perhaps the reason people have different experiences with different fertilizers is because:
1) different orchids, like many plants, are adapted to different environments and need different nutrients
2) different mediums retain nutients differently
3) plants behave differently in various environments.
I do grow a variety of plants and I have many different fertilizers. Pond plants get one, fruit trees get another, the peach needs blood and bone meal, the blueberries need Ironite, the citrus gets a special formula, I have hollytone and plant tone, Epsom salts, miracle grow, an MSU formula, and some other orchid stuff, plus oyster shell (and other calcium stuff). Yeah, it is great fun.

I understand what you're saying and to some degree you're right on some points.

Although the K binding to substrates thing I will not touch with a 10 ft pole, because I don't know any better than to even discuss this point.

However...

What has been neglected to be mentioned, (not by you btw ), is that we're talking mostly about potassium, and it is a macronutrient, and that it is used by most, if not all, forms of higher plants for the purposes of a whole host of physiological functions, and it may even play a vital role in energy potentials. Potassium is also present in many, if not all, higher plants in rather large quantities, (hence why it is considered a macronutrient), and the excerpt that Fabian24 pulled up dealing specifically with orchids illustrates this point clearly! Not to mention, Isurus79's links have demonstrated that even epiphytic plants might have sufficient access to K in the wild. And just because the plant has access to the nutrient doesn't necessarily mean that it is solely passively uptaking K+ cations indiscriminately; along with passive uptake, there is possibly also an active mechanism in place that controls the uptake of this nutrient, (hence why I pulled up those articles about ionic pumps in plant cells in order to prove this point). These were some of my points.

So here's the tie-in...

Given what I said about K being a macronutrient and all that - and assuming those are factual statements, (which they are), then given the way that fertilizers are formulated and given the way people normally apply dosages of fertilizer to their orchids, in addition to a plant's physiological demand for the use of K+, and plant physiology; there appears to be no real concern for the likelihood of long-term K+ toxicity due to K+ accumulation occurring! In fact, it appears that the more likely concern would be K deficiency, if everything I said so far was true, (and so far, it looks to be so).

Plus, I currently can't find any reliable, comprehensive, or compelling evidence that can support the thesis of the likelihood of K+ toxicity being a serious long-term horticultural threat to orchid growers due to substrate accumulation of K in regards to plants/orchids. Nor was there any kind of reliable, comprehensive, or compelling evidence provided to support this claim. Therefore, I have difficulties believing in this claim's validity.

Watch guys, this is another way as to how easily I can knock out the claim of substrate accumulation of K+ leading to K+ toxicity...

You guys forgot that you had to do a routine maintenance chore called repotting, where you guys have to throw out the old potting media in favor of putting in fresh new media that does not necessarily have that accumulation of K happening. This is also yet another reason why it doesn't jive with me, and this a horticultural reason, something that most of us here actually get!

There, you wanted logic, you got it.

On the other hand...

Now, I'm assuming, people in the same boat as Tucker would actually like to know what the connection Ca2+ and Mg2+ has with K+, and that was what I have difficulties explaining, because I just don't know the answer.

Originally Posted by Fabian24

I don't really see the point of the discussion.


If somebody wants to starve his orchids of potassium, let him do it. Orchids, as most plants, can translocate K from older leaves to new ones. So he won't notice any symptoms for some time, and then the plants will weaken and die.

There are lots of scientific publications on orchid nutrition, and all of them report the same symptoms of lack of potassium.
Just to quote some paragraphs of a relatively new one:

[Ray]

Philip - I absolutely agree that there are likely a number of different reasons plants just "crap out". As I stated, the theory that potassium buildup might be part of it is merely one.

Fabian's comment about K+ being readily relocated within plants tissues is dead on. That suggest that when fed a low-K diet, the plants should go a long time before there are symptoms of a deficiency. But how long is long enough? My plants are in month 19, and I still keep a close eye on them looking for issues, but I have seen none. There are others that have used this diet regimen on their collections well beyond that, time-wise. To the best of my knowledge, the only negative seen in anyone who has decided to join the experiment was one lady who grows cattleyas outdoors in western Florida. She saw what she interpreted as "premature loss of older leaves" while the rest of the plant carried on quite well. The old leaf loss might be related, and might not. I certainly don't know.

I guess the bottom line to me is that there really is no need for folks to get so "uppity" about the conversation.

Each of us has our own reason for participating in these forums. I do so to share my own observations and learnings, and to gain from those of others, because right or wrong, they open us up to more information, and an overall greater understanding of orchid culture. Philip, I view you and many others here to be of a similar bent. Unfortunately, there are folks who prefer to keep their heads in the sand (or elsewhere), and only seem to post in order to tout their own presumed expertise.