low potassium concept is not sustained by analysis

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Roth

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Over the course of a study sponsored by Pacific Wide/Besgrow, and carried out at Lincoln University, the following points appeared on a Phalaenopsis Sogo Yukidian 'Clone' mericlone population used for the test:

* The media and root concentration were not related. Instead, the potassium contents of the roots was related to the media type used, but not the ionic concentration of potassium.

* The foliar concentration of potassium was not related to the root concentration or the potting mix concentration. As an extract of the whole analysis:

Coir : foliar concentration 56000ppm root concentration 23600ppm, media concentration 2073ppm
Orchiata : foliar concentration 35600ppm, root concentration 8688ppm, media concentration 875ppm
New Zealand sphagnum moss foliar concentration 44000ppm, root concentration 18600ppm, media concentration 1914ppm
Us fir bark : foliar concentration 41600ppm, root concentration 10370ppm, media concentration 1100ppm

The US fir bark had the poorest leaf color of the various potting mixes tested ( here are only 4 as samples, but the total study encompassed 8 different potting mixes), with a low potassium value. There is no correlation between plant growth, quality and potassium content of the potting mix apparently...

As for the plant quality, weight, size, and leaf color have been assessed. It appears that the plant quality and strength was not related to the potassium concentration at all.

There are many more data from that study, being currently processed. However, it appears that we cannot find any intoxication by potassium, and there was no correlation between plant health and potassium. Other intermediate measurements are not included here, but plants are not intoxicated by potassium. The calcium and magnesium levels were not correlated to the potassium content either...

More will be published in the coming months out of the whole study.

We could say that maybe some other genera and species would respond well to the low K concept, but I do not use it, and many people neither. However, I use ammonium and urea in the feeding program, which always gives superior results, regardless of the potting mix used...

The low potassium could work well in the case of an all nitrate fertilizer only, because the nitrate force an ion. However, with the use of the monovalent cation ammonium, I have the feeling that the results would be the same, but superior.
 

Roth

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Who is Pacific Wide/Besgrow?

www.besgrow.com

The producers of Orchiata and NZ Sphagnum moss... We designed a study to compare the various potting mixes, from deflasking to blooming plants, to see what are the differences.

Indeed, there are a lot of differences between the potting mixes and the feedings, which can go from simple to double size and number of flowers.
 

Secundino

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That means that root concentration of potassium is aprox. 10x (8,78-10,61) the 'media concentration' - regardless of the medium. But what exactly means 'media concentration'?
 

Roth

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That means that root concentration of potassium is aprox. 10x (8,78-10,61) the 'media concentration' - regardless of the medium. But what exactly means 'media concentration'?

Analysis of the media with total extraction, so it is the total potassium contents of the media, locked or not...
 

gonewild

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I'm not sure how these results support your thread title "low potassium concept not sustained by analysis".

What you report indicates that potassium content of the media has little effect on the leaf tissue content. But how does this relate to the low potassium content which I assume you mean to be fertilizer nutrient ratios?
 
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Cheyenne

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Oooohhh....... This is going to be good. I can't wait to hear the responses. I am patiently waiting with popcorn for the show to begin!
 

orcoholic

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Thanks Roth. Please keep us updated with any information as soon as you get it.

There has been a lot about K-lite on this site and all the results seem to have been very good. This may be due to the users paying more attention to their fertilizer regime than they did before they went to K-lite. It also could be due the amount of N is increased relative to the P & K.

I create the K-lite be adding ammonium and Calcium nitrate to the RO Formula and the 20-10-20 Peat Lite formula. (I use both) The results I saw were so fast I could only assume it was the increase in N that caused it.

In my experience, there has been very good leaf growth, but the growth is definitely weaker and some of the tender newest leaf growth has defects. The defects could be due to the excessive heat during a couple weeks in July. I haven't been using it long enough to see flowering results.

These above observations are largely for phals. The Paphs and Phrags are putting on very good all around new growth.

Keep us informed.
 

Trithor

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Am I correct in understanding that medium concentration is a total value of the substrate and whatever has been added? (ie, if the medium was rock chips such as Kimberlite, which is an ultrapotassic igneous rock, the potassium levels would be stratospheric even if the K is not available to the plant at all?) Surely you need the free/available K level of the medium to have any grounds for comparison? Again as a carpenter, not a scientist (I too am getting my popcorn ready, and uncorking a good bottle of red wine for this debate)
 

Rick

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Yes. Please post the whole study when available.

The numbers you are posting are so far into the range of non environmentally relevant that I would not expect any normal foliar or root ratios of Ca Mg or K. Incidentally you didn't present any values of Ca and Mg to compare with tissue K. That's been the problem with all past GH studies in that they start out at already high levels of K and go on from there.

So you are getting what's to be expected with Lance's analogy of "butter on corn".
 

gonewild

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Just to get it said and then we can debate the trial results....

A New Zealand university does a trial funded by a New Zealand company that sells new Zealand bark and the result shows that New Zealand bark is the best media and North American bark is the worst media.

Typical corporate funded trial results.

Now when it comes to the discussion about the "low potassium concept" we don't care what brand of bark is best so Roth, how do these trial results relate to the potassium content of fertilizer?
 

Secundino

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Analysis of the media with total extraction, so it is the total potassium contents of the media, locked or not...

That is indeed interesting. Regardless how the potassium is present in the substrate, the plants manage a concentration (in the velamen covered roots) ten times higher. That means the roots either take potassium actively until this gradient or there is a passive potassium-trap that works the same way (or both). It makes sense to ensure the uptake of potassium for epiphytes as potassium is an essential nutrient.
But what happened in the study when fertilizing adds soluble potassium?

This gradient makes me wonder if there are more electrolytes involved in the potassium uptake...
 

Roth

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Just to get it said and then we can debate the trial results....

A New Zealand university does a trial funded by a New Zealand company that sells new Zealand bark and the result shows that New Zealand bark is the best media and North American bark is the worst media.

Typical corporate funded trial results.

Now when it comes to the discussion about the "low potassium concept" we don't care what brand of bark is best so Roth, how do these trial results relate to the potassium content of fertilizer?

Honestly, it has nothing to do with the brand of the bark, and the trial was done really blinded. It was expected however that the NZ bark would perform better than the US fir bark, and this is something that is already known by the professional growers, otherwise why so many commercial pot plant nurseries, including Europe, ran internal trial and chose to use orchiata, even at an increase in cost.

The EU nurseries that made trials and are using Orchiata now pay nearly double price for orchiata compared to their old media, mostly due to transportation costs, but they are happy to do so because they see a tremendous improvement in the growth quality). So it has nothing to do with corporate funded results.

In fact, the background of the study, and what will be made public at a later time ( the analysis have been extensive, including arsenic, chromium, even lithium...), was not to promote the Orchiata or New Zealand sphagnum moss, but to try to explain why they perform better than US bark or Chile sphagnum moss. There are some elements of reply in fact in the remaining of the data. There are analysis of fresh media before potting, then media being used, then media at the end of the trial.

For the trial, it started with flasks of clone from Clone Biotech, until the plants bloomed, so it is pretty extensive.

The basis being that the sphagnum moss from New Zealand had nearly 2000ppm potassium, coir the same, yet the NZ plants were growing considerably better than the ones in coir. Orchiata had a low level of potassium, yet, the plants were identical to the NZ Sphagnum moss plants. Another media ( Dutch blend) produced good plants, and was even higher in potassium content.

For the fertilizer, it was a standard 6-3-1 20-20-20 Ca(NO3)2 MgSO4 blend, typical of the Dutch style of feeding. We decided to use that one because it is the most used type of fertilizer in the pro phalaenopsis growers, with reverse osmosis.

I'm not sure how these results support your thread title "low potassium concept not sustained by analysis".

What you report indicates that potassium content of the media has little effect on the leaf tissue content. But how does this relate to the low potassium content which I assume you mean to be fertilizer nutrient ratios?

The potassium content of the media has indeed very little effect on the foliar tissue content, and was not related to the plant appearance and quality ( on a grower's point of view, not as a disposable plant).

On one side, Rick is right, because the load of the leaves of the plants does not depend so much of the potassium concentration in the media. so at a point, too much potassium is just a total waste.

We did the analysis for the calcium, and orchiata had much more calcium in the leaves than the others, due to the added lime. Yet, it is very interesting to note that a little bit lime was more effective in increasing the calcium foliar content than lots of calcium nitrate, providing the fertilizer was an acidifying one.

All of this has been done on a pH for the fertilizer of 5.7, which is again the standard for phalaenopsis. The fertilizer used, the 3x20, is nearly only urea with some ammonium, + the calcium nitrate, which brings some nitrate, so it is an acidifying fertilizer.

Now, to sum up a bit further about the fertilizer. I think K-Lite performed better than the MSU for some growers because in the MSU, the all nitrate ( the percentage of ammonium is ridiculous) force the plant to take up a cation, which is easier to take if it is potassium, a monovalent one. In this case, the MSU could well cause problems that the K Lite solved.

Rick solved the problem by lowering the potassium, and increasing the calcium and magnesium. But this still has the risk of potassium deficiency, and we force calcium and magnesium.

I am certain, even looking at how many growers are successful, that increasing a bit the potassium ( a high K fertilizer would seem to be foolish, because it seems that the plants have a maximal uptake level, and they cannot be intoxicated by the potassium truly), and using ammonium nitrogen instead of nitrate, at least 50/50, or using urea, would solve the whole problem. If anyone reads on the forum other posters, many report increased growth by using ammonium and urea fertilizers, and the growth will not be soft and weak.

We made a trial of an all nitrate MSU vs. the Dutch formulation given above, in several potting mixes. This is another study. And it appeared that the MSU plants looked really crappy compared to the Dutch formulation ( 202020 calcium nitrate magnesium sulfate, lots of urea and ammonium). They looked weak and starved. The only noticeable difference was the nitrogen contents of the leaves and the nitrogen source... Apparently nitrate does not so good a job to supply nitrogen compared to ammonium or even urea.

The fertilizer results were not related to the pH or whatever, because Orchiata has lime and is buffered, the sphagnum mosses we tested had a low pH, standard for sphagnum, US bark was of low pH too, and no carbonate contents for the last 3.

To another interesting notice, some bacteria and microorganism can make up ammoniac and ammonia therefore in the potting mix. Rick plants are indeed in excellent shape, but it could well be related to the microflora present around his greenhouse. Seaweed is being investigated, and it is a source of nitrogen, no matter the low analysis. Most of the nitrogen is available as amino acids in the seaweed ( and the potassium content is quite high in the Ascophyllum nodosium seaweed extract, like Maxicrop), and the plant takes those up readily.

So the K Lite could well benefit from increasing the potassium a bit, and adding at least 1/3 ammonium, it would be worth testing, even a K-Lite:ammonium nitrate blend at 1:1 or 2:1 if anyone wants, to see how the results are...
 

Rick

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What are the ratios of K, Ca, Mg in the leaf and root tissues under the different regimes? In wild plants you should end up with higher concentrations of Ca than K in leaves. But as you noted, this study was working with a highly selected cultivar growing under artificial conditions (even for a Phalae).

In the old Cornell study, you could not "force" Ca and Mg into hybrid orchids as long as the available K was greater than 50ppm (the Ca was held at 200 ppm). But after 30+ years of cultivation I would expect to develop a plant capable of utilizing unnatural levels of nutrients. All kinds of salt tolerant crops are being developed every day.

These results are similar to the bromeliad study with regards to luxury uptake of K. Lots of K piling up in tissue and not related to any positive/negative growth aspects (in a 12 month study).

You mention the aspect of microbial uptake of nitrogen (which probably accounts for the bulk of actual pot uptake in culture. 2000 mg/L of nitrifying bacteria (that would be equivalent to 2 grams of bacteria in a 4" pot. Can suck up 100's of mg of ammonia in an hour (converting it to nitrate). Unless you were feeding hydroponically the plant only has a few seconds to pick up anything while the bacteria coating/permeating the substrate will take up and convert ammonia absorbed into the media much more efficiently than the plant can utilize. Keeping the pH lower than 5 reduces the effectiveness of nitrification.

With a high % nitrate feed, fed at very low rates (under 10ppm) on a frequent basis, you will get a whole different microbial composition, which in general will be sparser, more diverse, and able to maintain a stable pH without pot supplements.

This study is still primarily dealing with pot chemistry. Much of my personal collection improvements (especially for Phaleanopsis) is for mounted plants, with virtually no complications of pot chemistry at all to consider.

I would really love to see a study of leaf tissue values on plants grown SH at environmentally relevant concentrations of nutrients.
 

paphioboy

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But after 30+ years of cultivation I would expect to develop a plant capable of utilizing unnatural levels of nutrients. All kinds of salt tolerant crops are being developed every day.

Yes for crops, and maybe phals. But for species paphs, a large number are not likely to be beyond a couple of generations from wild-collected plants. Would the nutrient-uptaking abilities of this cultivated progeny be significantly different from their wild ancestors?
 

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