nutrient deficiency symptom in orchids

[cnycharles]

Generally you can't use physan safely on young plants without some chance of burn, which was the recommendation I'd heard from fellow growers of flowering annuals, just a hard surface sterilant

 

[Bjorn]

Did we actually come to a conclusion in this thread? What causes the yellow spots? The reason for asking is that I recently saw a similar pattern on one of my kovachiis

 

[naoki]

Bjorn, the white band slowly greened up over a month or so. If I have time tonight, I'll post the updated photo. I can't say much from this 1 incidence, but I'm tempted to think that myxodex's suggestion of S could be the likely cause in my case. If CaSO4 is the precipitate, S could be all gone (since there are higher number of Ca molecules in MSU). Also phloem mobility of S is intermediate, so it somewhat matches with the observation (the relatively newly growing tissues are influenced, and it can be recovered after a while). But I changed quite a bit of things (started to add small amount of MgSO4, EM-1 etc), so I don't know the exact cause. When the plant becomes a bit bigger, I will try to induce the white strip again (with the precipitated MSU).

How are you growing your P. kovachii? I'm a bit worried because my seedlings (2-3cm leaf length, deflasked last spring) seem to have growth spout and stationary phase. It could be temp related, but my indoor condition doesn't have lots of seasonal variation in temp. I checked the pour-through pH, and it was ok (about 6.7). I sprinkled additional Dolomite Lime granules, and they seem to resume the growth a little bit recently (but it could be spring thing). I'm using fine bark based mix with some sphag, and bottom water tray. Top water every other day (so they are continuously wet).

 

[gonewild]

How are you growing your P. kovachii? I'm a bit worried because my seedlings (2-3cm leaf length, deflasked last spring) seem to have growth spout and stationary phase. It could be temp related, but my indoor condition doesn't have lots of seasonal variation in temp. I checked the pour-through pH, and it was ok (about 6.7). I sprinkled additional Dolomitic Lime granules, and they seem to resume the growth a little bit recently (but it could be spring thing). I'm using fine bark based mix with some sphag, and bottom water tray. Top water every other day (so they are continuously wet).

If you add crushed limestone to your media they will grow faster.

 

[naoki]

White stripe on the top left leaf became mostly green after 5 weeks.



Thanks, Lance. Is limestone (CaCO3) better than Dolomite (CaMg(CO3)2)? I think the pH is not so far off from the natural habitat pH which Rick posted.

 

[gonewild]

Thanks, Lance. Is limestone (CaCO3) better than Dolomite (CaMg(CO3)2)? I think the pH is not so far off from the natural habitat pH which Rick posted.

I do not know the answer to which is better. I suspect they will give equal results.

I did a trial that proved that the addition of physical pieces of limestone mixed in the media improved the growth of kovachii.For the crushed limestone I used I used pieces about 6-10mm in size and it was limestone I collected from a river levee so I do not know the chemical form of limestone.

The reason I suspect the form of limestone may not matter is because in the trial I also used oyster shell as one variable and the results were equal.
The growth improvement was not because of a rise in pH because I covered that variable also. I concluded that the roots benefited from direct contact with limestone.

 

[Ray]

If one adheres to the notion that plants tend to use calcium and magnesium together, I'd think the dolomite would be a better choice.

However, as far as nursery-grade carbonates go, they never are exactly formulaic - CaCO3 always has some Mg in it (and in dolomite, you'll never find one that has exactly a 1:1 ratio).

 

[gonewild]

If one adheres to the notion that plants tend to use calcium and magnesium together, I'd think the dolomite would be a better choice.

However, as far as nursery-grade carbonates go, they never are exactly formulaic - CaCO3 always has some Mg in it (and in dolomite, you'll never find one that has exactly a 1:1 ratio).

I suppose if you want to make a choice you should consider the amount of magnesium applied with the liquid feed.

After the results of the trial I did my opinion was that the limestone did not improve the growth as a result of adding extra nutrients. I think there is some reactive association between the actual solid limestone and the root.

 

[Stone]

I found and still find this study interesting. It shows a relationship between Ca and Mg. It shows that what is important when growing plants from alkaline systems (in this case at least and not that kovachii grows very alkaline), what is important is the Ca/Mg ratio rather than the pH or the even the final concentrations of these elements.
The ratio is worked out as Ca divided by Mg.
They grew equally well at pH of 5.5 and 7.5 as long as the Ca/Mg ratio was was over 4 and possibly below about 10. It also may mean that when selecting materials, plain limetone or a 50/50 mix of dolomite and limetsone may be a better choice in some cases. Very interesting!

 

[naoki]

Thank you for your trial info, Lance. Very interesting, I wonder what the cause is. I should give it a try.

Thanks for the info about Ca:Mg, Ray and Mike. I think it is from this book:
https://books.google.com/books?id=d...gTM2IHwDw&ved=0CB4Q6AEwAA#v=onepage&q&f=false
I should get this book.

 

[Stone]

Thank you for your trial info, Lance. Very interesting, I wonder what the cause is. I should give it a try.

Thanks for the info about Ca:Mg, Ray and Mike. I think it is from this book:
https://books.google.com/books?id=d...gTM2IHwDw&ved=0CB4Q6AEwAA#v=onepage&q&f=false
I should get this book.

Yes and yes

 

[Bjorn]

Naoki, thank you for update, this thread is transforming into something very interesting. I am currently travelling, so not much can be done right now, but will be home again tomorrow, My spots may be of another origin, as they seem to have a kind of necrotic center almost as if something chewed on it. But there is this replica like thing on the adjacent leaf just as you had. I changed my fertiliser some time ago, and this may have been caused during a period without fertilising. My water should contain plenty of nutrients though also sulpur so I do not think it is that. Might have been lack of Mg though. what are the "experts" opinion to that?

 

[gonewild]

Thank you for your trial info, Lance. Very interesting, I wonder what the cause is. I should give it a try.

I have only guesses as to what the cause might be. It may have something to do with energy exchange. Perhaps the mass of limestone is a catalyst to nutrient uptake? It's easy to measure minerals and chemical elements present it plant tissue and the surrounding environment but we have no real concept of how and why those elements move around, change form and make a shape. There is more to it than just the actual nutrients.

Mixing limestone into the media won't have a negative effect so trying it is zero risk. If you decide to try it I suggest that you continue liquid applications of Ca and Mg as normal and not assume the limestone will provide those nutrients.

 

[naoki]

Bjorn, it would be interesting to see the photo of your chlorosis. Mg is unlikely to cause stripes in theory. But "theory" may not apply to all plants.

Certain key nutrients (N is usually considered to be the limiting factor in nature) promote the growth, and I'm speculating that we see white stripes when plants get activated even though some other key nutrients (something which is less mobile) are missing. The white stripe appeared on mine when it was rapidly growing (after slow period) indeed. It started to grow suddenly when I moved from cooler area to more intermediate temp region.

Lance, that's beyond what I understand about plants. I guess touching to a rock could initiate some different metabolism in the root.

Ca is supposed to be a double edge sword (much more than K), and for garden plants, too much liming can cause lots of problems as you know. So it is not completely risk-free. But I'll try mixing (instead of topping).

 

[gonewild]

Lance, that's beyond what I understand about plants. I guess touching to a rock could initiate some different metabolism in the root.

It is beyond what anyone understands about plants. That's why it is a guess. But it is something some "scientist" should consider and look at, something beyond the common concept.

Ca is supposed to be a double edge sword (much more than K), and for garden plants, too much liming can cause lots of problems as you know. So it is not completely risk-free. But I'll try mixing (instead of topping).

But we are not talking about garden plants growing in clay soil. Adding limestone to media for Phrags is risk free, specifically for kovachii it is zero risk since it grows naturally in broken limestone and organic matter.

 

[Stone]

Adding limestone to media for Phrags is risk free, specifically for kovachii it is zero risk since it grows naturally in broken limestone and organic matter

I presume you mean old weathered pieces and not raw, ground powder?

The limestone around wild kovach is highly aged and coated in bacteria, fungi, algae, moss, humus etc.

The ground powder is very reative

 

[gonewild]

I presume you mean old weathered pieces and not raw, ground powder?

I said crushed limestone 6-10mm in size. Not soluble powder.

The limestone around wild kovach is highly aged and coated in bacteria, fungi, algae, moss, humus etc.

I know exactly what the limestone organic substrate around wild kovachii is like, I've held it in my hands. That is why I did the trial to test it. The limestone pieces are actually not that weathered they are fractured pieces with fairly sharp edges basically still in place. It is not a substrate that would be easy to manage in pots.

The ground powder is very reative

Read what I wrote. I said not ground powder because the purpose is not to supply Ca or Mg as nutrients, it's to provide physical contact.
In my trial I supplied plenty of nutrients in the fertilizer solution with differing Ca levels so I know the improved results were not due to a simple increase of nutrients. I have measured the pH and EC of water flowing over limestone here in the Andes, surprisingly the pH is neutral and the EC is zero. Water dissolving limestone and running over roots does not seem to be a major source of the Ca.

 

[Bjorn]

Promised to show my kovachii with spots, well here it is:

Another one had indications as well

but the plant seems to be quite vigorous though

It is my perception that these spots may have formed during a period with reduced growth (or is it during onset of active growth?) and that they slowly are fading now. I have it only on these two kovachii's no other phrags. Could it be a deficiency? I stopped fertilising for a couple of months during late fall/Winter which is approximately when the spots were formed. Since I use rain and bog-water, that sounds a bit unreasonable though. Comments?

 

[gonewild]

I don't think it is a deficiency. I had a couple kovachii seedlings have the white while in the flask and they kept it for multiple years and on new growths. I suspected they were genetically variegated. But I also realized the variegation could have been a result of a nutrient deficiency so I tried a lot of nutrient additions and variations to try to reverse the chlorotic color if that is what it was. Additional nutrients had no effect or aid in making the variegation disappear. I tried lighting from deep shade to nearly full sun with no effect. Temperature had no effect. It seemed the plants were actually variegated.

The final test came when these two plants had to stay with my MIL for a siz month period while we were on an extended trip to Peru, (I was growing them in California). She cared for my two rare variegated kovachii well right along side of her African Violet and potho and cactus and one Phal. She knows nothing about fertilizer so I told her not to feed them anything special just give them what she gives her other plants, which is basically nothing.

When I returned 6 months later the plants were in good condition with completely green leaves. So much for the variegated special plants.

After this long story I now believe these white color areas on leaves are the result of a nutrient excess or imbalance of some sort. I never tried reducing the nutrient level to extreme low levels, but she did and the white went away.

But why did only two plants out of my 150 kovachii seedlings have this? The answer has to be genetics since they were that way in the flask. There were actually 4 plants that had the condition but only two had defined pattern the other two were consistent with the leaves you show here.

I believe this condition is a genetic anomaly that reacts to one or more nutrients in excess.

 

[gonewild]

Here is a picture of the kovachii plants just before I left them with my MIL.
It's a cell phone picture so not the greatest resolution but it shows the variegation. The plants had just finished wintering outside and and survived frost. During the winter they got watered at least once per week with K-lite at 100ppm N and I attribute the survival of the wet and cold to the low potassium from the K-lite. But that's another story.

Previous to using K-lite the plants were fed nutrients based on MSU.