Pale yellowish leaves - why????

[Happypaphy7]

I see that you want to emphasize on the proper nutrition which of course is very important for any living things, but your saying vast majority of paphs gone are due to improper feeding can hardly be true.
As I'm sure you know very well that many factors cause the loss of them.
Nutrition is just one part of the picture. Improper temperature range, insufficient watering and low humidity among other things can really ruin lots of plants.
I've seen greenhouse full of half baked or frozen plants as a result of system shut down or severe weather conditions.
I've seen badly diseased plants marked 50% off at nursery sales (of course I won't even take them even if they paid me to take them lol) and plants covered in mites and mealies crawling around on the flowers and leaves.
Or plants being sold to wrong people who just have no idea how to grow plants.
I believe most seedings and near blooming sized plants sold to general public will suffer because of improper handling and culture of the plants. Improper nutrition will be one of the many problem, not the ultimate cause.

There's a big misunderstanind among many people. They see something impressive or simply something they like and often the first thing or the only thing they ask is what do you feed? I am highly irratated and tell them nothing. lol
They think by fertilizing with certain products or certain frequencies, they can make their plants go bonkers and bloom well.
They completely lack or disregard the whole picture. Proper temperature range for different plants and proper & good watering, starting with healthy strong plants, proper light level...but no, always one things, what do you feed? Sigh~

 

[Roth]

I see that you want to emphasize on the proper nutrition which of course is very important for any living things, but your saying vast majority of paphs gone are due to improper feeding can hardly be true.
As I'm sure you know very well that many factors cause the loss of them.
Nutrition is just one part of the picture. Temperature range and water among other things really ruin lots of plants.
I've seen greenhouse full of half baked or frozen plants as a result of system shut down or severe weather conditions.
I've seen badly diseased plants marked 50% off at nursery sales (of course I won't even take them even if they paid me to take them lol) and plants covered in mites and mealies crawling around on the flowers and leaves.
Or plants being sold to wrong people who just have no idea how to grow plants.
I believe most seedings and near blooming sized plants sold to general public will suffer because of improper handling and culture of the plants. Improper nutrition will be one of the many problem, not the ultimate cause.

There's a big misunderstanind among many people. They see something impressive or simply something they like and often the first thing or the only thing they ask is what do you feed? I am highly irratated and tell them nothing. lol
They think by fertilizing with certain products or certain frequencies, they can make their plants go bonkers and bloom well.
They completely lack or disregard the whole picture. Proper temperature range for different plants and proper & good watering, starting with healthy strong plants, proper light level...but no, always one things, what do you feed? Sigh~

Well the nutrition is kind of everything, the remaining is not really that important.

Plants are much more tolerant to a wide range of temperatures and light than most people admit. Otherwise, it means that 99.9995% of all the orchids ever sold, including thousands of sanderianums, gigantifolium, bougainvilleanum, were all sold to the wrong people...

If you look at my photos on Facebook, all is grown in the same greenhouse, same conditions. This afternoon, the entire greenhouse had a PAR of 700-800, max temps of 34 degrees celsius ( but fog system to keep the humidity high...) and I don't think my plants look sick.

The roth that I posed in february though have made a new growth that is now in full bloom and several side shoots. next to them, the cuthbersonii are happily clumping and blooming...

The only thing, I control the feeding and the substrate pH to near perfection...

 

[Happypaphy7]

Nutrition is kind of everthing and the remaining is not really that important.
Simply not true.
For a few that you listed, 34C is not that much of a deal actually. And I'm sure you know that, too. So those are not the right example to back yourself. I bet you are also very well aware that certain plants live in certain climates for reasons. They have evolved to function the best in those given conditions. Temperature is very important for biochemical processes and of course, you know that well too. Taken to extremes, but extremes seem like your specialty, so grow Edelweiss on hot house and let's see how you do.
I bet no matter how perfect the pH and feeding, they simply will perish.
So please stop making false statements.
I guess I'll just have to say we agree to disagree. Adios!

 

[gego]

Let me join the chorus lol. I will not take sides, lol. I think what you guys are saying have their own merits. ALL cultural variables are necessary and we all know that.
Information on cultural requirements like light, temperature, air, water and humidity are readily available and can be achieved if one do so. The input and output of these variables can be measured and controlled. Any serious grower/collector can meet these requirements. Except nutrition. We can measure and control what we are providing but we never know what actually are absorbed and not absorbed and why or why not, until such time we notice something is not right. Or sometimes a few of the plants are doing well but we really don't know why they prefer that feeding. Or some of them look okay and acceptable to the grower and leave it that way. It's not optimal but hey it's growing.
But if we only know how and what to adjust our feeding to get the optimal growth, I bet we all will do it. Very few of us are active growers, meaning we continously experiment to learn more and adapt. A lot are passive growers, where they do what they have read or what they have been told or heard. And come what may. There are members here who have one way or another closely figured this feeding out. You can tell because they don't get into this discussion anymore..I or maybe they are just tired of these same old topic.
But I do agree that any
information about all nitrate only is good for orchids and
advises to use 20 20 20 instead should be removed.

 

[Ray]

As far as I'm concerned - even though I focus on it quite a bit - nutrition is quite low on plants' "Maslow's Hierarchy" of priorities. Water is a lot higher.

Just about any plant is 95% water or thereabouts. The dry matter is typically 99% C, O, H, and N., with P, K, S. Ca, & Mg being the vast majority of that remaining 1%, with everything else (the "trace elements") being the minuscule balance.

In order to complete the chemical reactions that bind carbon (otherwise known as "growth"), the demand for water far outweighs that for fertilizer, in fact the ratio is somewhere around 18000:1 by mass. Throw in the fact that plants can lose as much as 95% of the absorbed water through transpiration, and the ratio gets more extreme, on the order of 360000:1.

You want to grow and bloom your plants well? Find a way to provide copious water without suffocating the roots, give it a little fertilizer on a regular basis (the formula is less critical than folks think, although there is no doubt some have nutritional preferences), and make sure the rest of the conditions are correct for the particular plant.

 

[spujr]

Just asking to learn more: what is the ammonium/urea source for orchids in the wild and any idea on those concentration levels?

 

[Roth]

Nutrition is kind of everthing and the remaining is not really that important.
Simply not true.
For a few that you listed, 34C is not that much of a deal actually. And I'm sure you know that, too. So those are not the right example to back yourself. I bet you are also very well aware that certain plants live in certain climates for reasons. They have evolved to function the best in those given conditions. Temperature is very important for biochemical processes and of course, you know that well too. Taken to extremes, but extremes seem like your specialty, so grow Edelweiss on hot house and let's see how you do.
I bet no matter how perfect the pH and feeding, they simply will perish.
So please stop making false statements.
I guess I'll just have to say we agree to disagree. Adios!

To conclude this discussion, I was asked by a customer to grow Disa, in pots (no recirculating water), standard watering schedule ( drying out between waterings), Phalaenopsis cooling house ( 17-23 degrees constant), and that could stand of the summer greenhouse temps ( 28-35 degrees...). at first they wanted a 20cm diameter product, took 6 months. Then 30cm, 10 months. Here we are. EC 1600 microsiemens, same feed as the Phalaenopsis, 1kW HPS 14 hours a day. Peat based mix ( not rockwool...) as that's what they wanted. Divisions of these plants are still posted on Internet today, so they were... long lasting to say the least!

Though the customers of the grower that requested these decided to grow them in the 'good way', cold, running water, so now they are 10-12 cm, and the leaves become yellow around flowering time... Another 1-2 years and they will be gone, because they are 'short lived'...

The only things that were adapted was the potting mix pH ( much higher), and the micronutrients...

 

[Tony]

Just asking to learn more: what is the ammonium/urea source for orchids in the wild and any idea on those concentration levels?

Animal waste would provide both, and ammonia is the first nitrogenous compound produced when any organic material decays. Conversion of ammonia to nitrite and nitrate occurs through bacterial metabolism.

 

[Ray]

There seems to be an insistence that urea is necessary for plant longevity, yet I have plants that have had none for nearly 30 years.

 

[gego]

For me, pH is the main factor. When pH is not matched with the plant, plants have a hard time taking these ionic form of nutrients. It's almost like swimming against the tide. This is a common knowledge not theory but a fact. Orchids are plants.
There are ratios also of cations and anions that need to be considered. Their forms and ratios make then either easily get absorded or easily tied to another ions. Also this is a common knowledge.
Experiment.
Very interesting exchange of ideas and experiences.

 

[wongwong]

The only things that were adapted was the potting mix pH ( much higher), and the micronutrients...

1) For mounted plant /mostly bare root plant with least medium interaction, what to buffer root pH?
2) To conform, pH range suggested in pdf “Orchid Growing Substrates” 5.7; 5.5-6.2 refers to pot / drainage pH rather than irrigation input; saying pot lime do raise back pH
3) Won’t urea lysis raise pot pH in short term?
4) Did you try differentiating the benefit of lime as pH down restriction or root zone CO2 enrichment (or calcium enrichment)?
Do root zone CO2/HCO3-/lime adaptation determine the root: shoot ratio?
Should I consider paph. as C3 plant with low gaseous exchange?

5) Did you differentiate the benefit of urea against ammonium apart from pH drift? saying with urease inhibitor

 

[Russ1992]

I’ve been growing paths for more than a decade and have over a hundred of them. I have always had a problem with leaves turning yellow. Losing the healthy green color. I buy a beautiful green paph and a year later it is pale and yellowish. I'm not talking about normal senescence of old leaves. I suppose the plant is stressed in some way. Why, oh why does this happen?



I don’t think it’s fertilizer, I regularly use MSU fertilizer, as well as monthly Kelp supplement.



I don’t think it’s light, I grow under LED lights.



I repot annually in orchiata/sponge rock mix.



I water when they approach dryness, 2 - 3 times a week, and most plants have great roots when I repot them.



Could it be my water? We have some of the purest water in the country, very low TDS, but I’ve recently installed an RO system to see is that makes a difference.



Please, any suggestions? I've got to figure out what to do differently. This is driving me crazy!



Photos are two seedlings of Ho Chi Minh, all pale and bleached out, next to a smaller green micranthum for comparison. The other photo is of a multifloral with great roots and growth, just yellow and pale, next to a greener bulldog for comparison.View attachment 41537View attachment 41538

IF you are feeding enough (i.e. around 100ppm of Nitrogen a week) I suspect it could be a water quality issue in the form of too much salt since your TDS is low.

I use rainwater, BUT I am by the ocean and this means there is a higher chance of salt content in my rain compared to if I was inland.

Flushing more frequently has shown noticable improvements in every sphere of the plant; including yellowing.

Just like you I have clear root growth and new burgeoning shoots on about 20 different paph species; but nearly all seemed stunted and yellow/matte/dull compared to when I first received them. My TDS is around 800 after K-Lite 100N and the PH on the strips or meter hover around 6.0 - 6.5. Light is 800 fcs. Mix is open and watering seems adequate. Air is warm and humid. That leaves water quality as the issue.

I've noticed over the years that the people who grow the very best paphs have either low TDS water such as RO/Distilled/Rain OR they flush more than once a month. Some will repot more frequently as well at least once a year or more.

Keep us updated.

I now suspect that one's water quality is far more important than nutritional supplementation.

 

[Ray]

IF you are feeding enough (i.e. around 100ppm of Nitrogen a week) I suspect it could be a water quality issue in the form of too much salt since your TDS is low.

Maybe I’m misunderstanding that, but low TDS means, by definition, low salts. However, NaCl in solution is quite conductive, relative to most fertilizer ingredients, so I suppose it might be in a concentration high enough to be a cultural negative while still provide a low TDS reading - that is, IF we know for sure what the effect threshold might be.

 

[Russ1992]

Maybe I’m misunderstanding that, but low TDS means, by definition, low salts. However, NaCl in solution is quite conductive, relative to most fertilizer ingredients, so I suppose it might be in a concentration high enough to be a cultural negative while still provide a low TDS reading - that is, IF we know for sure what the effect threshold might be.

Yes, I should have said NaCl (Sodium chloride - aka Table Salt) instead of "salt." When I think of salt my mind always goes to NaCl instead of the other salts in the water like Magnesium sulfate.

Sodium, Chloride, and Boron at high enough concentrations can lead to ion toxicity and prevent the uptake of other nutrient mineral ions like Magnesium which is perhaps why Swamprad saw little effect of Epsom salts greening up his plants. That has been my experience too with Epsom Salts. I literally gave 1 teaspoon per gallon weekly 3 or 4 times consecutively with basically no change in greening up leaves. Perhaps the water has just enough of these touchy ions to accumulate over time and cause noticeable problems if there is just a monthly flush.

Regarding my rainwater, reputable sources say all three of the beforementioned ions can be present in higher concentrations in coastal rainwater in comparison to inland rain.

With all this being said, it is possible Swamprad is just not fertilizing enough since we don't know their Nitrogen PPM.

 

[Ray]

Getting a nutrient balance is important.

For example, N, K, Ca, & Mg can all occupy the same initial sites within the plant. An excessive level of one can therefore block the uptake of the others. Now, knowing what constitutes “excess” is another matter.

 

[big923cattleya]

TDS = total dissolved salts no matter what the source of those salts might be.
At least that is what I learned that it meant.

 

[eds]

TDS means total dissolved solids and should include all things dissolved in the water including inorganic salts and organic matter.

 

[Ray]

Unfortunately, people take TDS to mean “what my cheap TDS meter reads”, and they’re usually very inaccurate.

True TDS determination of an unknown solution involves weighing the solution, evaporating all of the solvent (water) and weighing the residue.