Browning Leaf Tips

[richard.feldman48]

Hoping someone can help me identify a problem with a phrag. It's labeled QF Angel wings (Phrag. Grande x Phrag. Incan Treasure). It's growing in LECA, fertilizing with K-Lite at very low concentrations (25 ppm), RO water. (Also, Kelpmax and Quantum Total. i.e, Ray's method.) I looked at the photos at the St. Augustine Orchid Society site. It looks something like the images of anthracnose, but also a little like those of calcium deficiency. But, of course, it could be something else entirely. I have a hard time with these identifications. Advice appreciated.

Rich

 

[Happypaphy7]

I would rule out calcium deficiency unless you have a good reason to think it is calcium related.
One thing I'd like to say about Phrags is that this issue seems fairly common when I visited some nurseries with good number of phrags. Almost all the phrags they had with very few exceptions, looked pretty much the same as shown in your photo or had their leaves heavily trimmed off. The commercial nurseries feed their plants on a regular basis. So, it can't be calcium deficiency and honestly, they don't look typical of calcium deficiency to me.
Anthracnose is a high possibility as I had one phrag that had this same symptom which stopped progressing further when I applied antifungal agent on the affected area. Fungus is everywhere and some plants especially under less-than-ideal conditions fall easy victim to fungal diseases.
Another phrag, my very first phrag, also showed similar issue, but it was due to dehydration. I was keeping the plant too dry. I switched the plant to wet feet condition as suggested and ta da! The plant just took off growing like a weed.
So, I would check first to see if you are watering your plant enough at all times. I saw Phrag Grande being grown in the bucket full of water. Some of these phrags really do like to have a lot of water always available at their roots.
Then, try spraying the antifungal and see if that stops any further damage on the leaves.

 

[Ray]

Rich, there are a number of things that can result in leaf-flip dieback.

• How long has it been in that pot?
• Was the LECA thoroughly cleaned prior to use? (If it’s only been a short time.)
• Does “in LECA” mean semi-hydro, or just as an inert medium? (I see leaf-tip die back if I get lazy and they get too dry.)
• How often are you watering and feeding it?

Of course, it could be a disease, but I usually blame such things on slips in my own culture, more than anything else.

 

[richard.feldman48]

Thanks for the replies.

Ray - it has been in the pot for about 9 months. Yes, the LECA was cleaned well. It is semi-hydro. I water twice a week, with the very low concentration K-Lite. I’ve assumed the problem was in what I was doing rather than a disease, but the photos made me question that assumption.

One thing that I don’t do is to flush it with water w/o fertilizer. I thought that filling it with low concentration fertilizer solution was good enough. Maybe not?

Rich

 

[big923cattleya]

I have been growing Phrags for years and judging them on a regular basis. In my opinion pure Leca as a media is not a good idea.
They require to grow fairly moist and Leca dries out too much. Leaf tip die back can come from too much water but in Leca, I doubt that is the issue. I grow mine in 50% seedling bark, 10% charcoal, 10% perlite, 10% medium bark and 20% Leca. I use Hydroton buts it is basically the same.
I fertilize only one a month at 1/2 strength and water every 5 days or so under lights and every three days when they are outside for the summer. All are in plastic pots.
Too much fertilizer can burn leaf tips!

 

[Ray]

One thing that I don’t do is to flush it with water w/o fertilizer. I thought that filling it with low concentration fertilizer solution was good enough. Maybe not?

That depends upon whether your irrigation technique is flooding the pot with a large volume of solution, or something closer to wetting the LECA and refilling the reservoir.

I have been growing Phrags for years and judging them on a regular basis. In my opinion pure Leca as a media is not a good idea.
They require to grow fairly moist and Leca dries out too much. Leaf tip die back can come from too much water but in Leca, I doubt that is the issue. I grow mine in 50% seedling bark, 10% charcoal, 10% perlite, 10% medium bark and 20% Leca. I use Hydroton buts it is basically the same.
I fertilize only one a month at 1/2 strength and water every 5 days or so under lights and every three days when they are outside for the summer. All are in plastic pots.
Too much fertilizer can burn leaf tips!

All of my phrags are in 100% LECA in semi-hydro culture, so only get dry when I have been extremely lazy. Some have been in it for 20 years.

In a semi-hydro pot environment, the well-saturated LECA can stay moist enough to sustain a plant for several weeks after the reservoir is dry by keeping the root zone humidity elevated (not that I recommend that).

 

[richard.feldman48]

I flood the pot - filling it to the top and letting the water run out the holes an inch above the bottom.

Rich

 

[Ray]

Rich,

It sounds like you an I are doing about the same things and I’m not seeing that, so maybe it’s not cultural.

I just noticed a subtle (?) difference in the browning pattern: when I neglect my plants, whether that be letting them get too dry or letting the LECA accumulate to much waste (it happens), the leaf tips have a more gradual green to yellow to brown “fading”, and not a distinct green/brown “line” as that appears.

 

[alex.sorensen51]

on my 2 phrags, I think of it as aging...once the leaves reach a year , they decay,tip first

 

[Kalyke]

I am sure you will get lots of answers from very knowledgeable folks. I have/have had this issue too and I am interested to see what kind of advice you get. I chalked it down to "a change" in care, because after a while, it stopped. That doesn't mean there are not leaves that are scarred by it. I was feeding with my own water which is very high ppm and "liquid rock." The paphs love the high minerals, the phrags are more sensitive and tend toward liking rain water better. I discovered the issue started to feed with RO, and keep them sitting in water. I haven't seen it in new growths. I honestly wonder about the statement about LECCA-- I cannot see how an innert medium would add any chemistry to the plant at all.

I actually decided at one time it was the caudatum and Longifolium that did it, but most legitimate growers do not have this or they would never sell "Grande." It is a problem on my end, with my care, and not the genetics, or the breeder/grower would have seen it because it even happens to new growths.

 

[SelectOrchids]

potassium deficiency... Check the pH at the roots, use some hard water mixed in, add a high K fertilizer with urea, and the problem will disappear nearly overnight....

 

[Ray]

potassium deficiency... Check the pH at the roots, use some hard water mixed in, add a high K fertilizer with urea, and the problem will disappear nearly overnight....

I don’t think so.

That would only be the case if the plants had not been receiving any K for a long period of time, while all other nutrients are being supplied sufficiently. Potassium is one of the minerals that a plant stores an excess of, while recycling easily it within the plant.

Nutrient deficiencies are hard to diagnose from appearance, and more often than not, none are displayed, with a general slowdown in growth happening instead. Considering how slow orchids grow in the first place, that makes it all that much harder to identify.

Just a guess, but I’d lean toward some sort of bacterial infection.

 

[SelectOrchids]

I don’t think so.

That would only be the case if the plants had not been receiving any K for a long period of time, while all other nutrients are being supplied sufficiently. Potassium is one of the minerals that a plant stores an excess of, while recycling easily it within the plant.

Nutrient deficiencies are hard to diagnose from appearance, and more often than not, none are displayed, with a general slowdown in growth happening instead. Considering how slow orchids grow in the first place, that makes it all that much harder to identify.

Just a guess, but I’d lean toward some sort of bacterial infection.

That's for sure a potassium deficiency, and we studied Phragmipedium as a pot plant. it can be a direct one by lack of potassium, or an indirect one if the pH is too low or swinging too much. Urea helps as well to balance the plant growth, as nitrate is a poor source of nitrogen for quite a few species of Paphs and Phrags...

			N	K	Ca	Mg
Phrag 17-1 Perfect	ppm		13734​	17706​	8560​	2430​
Phrag 17-1 Brown tips	ppm		11830​	3537.3​	33960​	3863.7​

There are rows and rows like that in my database, and brown tips for Phrags = potassium deficiency. then I can say it is a potassium deficiency... Note that Ca and Mg can be toxic and block the potassium, if they are supplemented with a fertilizer containing nitrates...

Nutrient deficiencies can appear on multifloral Paphs as well as a 'bacterial rot', water soaked blotches that becomes brown and progress very quickly... A multifloral Paph will use about 30% of his potassium storage to make the flower spike and bloom. Once it fades, that amount is gone from the leaves.

On Phalaenopsis, the plants become yellow when they bloom, and it can happen over 1-2 weeks, the plant can lose nearly all of its leaves in such a short time, and it looks like bacteria. Those are extreme cases, but I saw them several times at several pot plant growers.

One problem with published papers about plant nutrition in the orchid world is that they are done voodoo style.... MSU or K-Lite were written as an example without any support. The use of nitrate only as a nitrogen source for orchids, that urea is not used by plants, etc... are as well voodoo quack science.

I gave an example before. Nitrate as a sole nitrogen source is better than urea when you use sphagnum without buffering or keeping the pH in check. But it is not the best nitrogen source. However, the problem is a too acid potting mix, and nitrate help the plants to suffer less. It is not that nitrate is better than urea or ammonium.

My experience comes from the management of millions of plants ( not exaggerating...), a dozen pot plant customers, including the 5 largest Phal growers in the world, expert for some of the largest orchid labs known, and hundreds of fertilizers trials with foliar, root, drain water and soil analysis, for Phalaenopsis, mottled leaf Paphs, strap leaf ones, even cuthbertsonii, cymbidiums, and many others. Different media, sphagnum buffered sphagnum oxygrow, bark mixes, rockwool... We even went to the lenght to use radiolabeled nitrogen sources at a point, and eventually proved that some orchids are fully unable to use nitrate efficiently as a nitrogen source...

 

[KateL]

That's for sure a potassium deficiency, and we studied Phragmipedium as a pot plant. it can be a direct one by lack of potassium, or an indirect one if the pH is too low or swinging too much. Urea helps as well to balance the plant growth, as nitrate is a poor source of nitrogen for quite a few species of Paphs and Phrags...

			N	K	Ca	Mg
Phrag 17-1 Perfect	ppm		13734​	17706​	8560​	2430​
Phrag 17-1 Brown tips	ppm		11830​	3537.3​	33960​	3863.7​

There are rows and rows like that in my database, and brown tips for Phrags = potassium deficiency. then I can say it is a potassium deficiency... Note that Ca and Mg can be toxic and block the potassium, if they are supplemented with a fertilizer containing nitrates...

Nutrient deficiencies can appear on multifloral Paphs as well as a 'bacterial rot', water soaked blotches that becomes brown and progress very quickly... A multifloral Paph will use about 30% of his potassium storage to make the flower spike and bloom. Once it fades, that amount is gone from the leaves.

On Phalaenopsis, the plants become yellow when they bloom, and it can happen over 1-2 weeks, the plant can lose nearly all of its leaves in such a short time, and it looks like bacteria. Those are extreme cases, but I saw them several times at several pot plant growers.

One problem with published papers about plant nutrition in the orchid world is that they are done voodoo style.... MSU or K-Lite were written as an example without any support. The use of nitrate only as a nitrogen source for orchids, that urea is not used by plants, etc... are as well voodoo quack science.

I gave an example before. Nitrate as a sole nitrogen source is better than urea when you use sphagnum without buffering or keeping the pH in check. But it is not the best nitrogen source. However, the problem is a too acid potting mix, and nitrate help the plants to suffer less. It is not that nitrate is better than urea or ammonium.

My experience comes from the management of millions of plants ( not exaggerating...), a dozen pot plant customers, including the 5 largest Phal growers in the world, expert for some of the largest orchid labs known, and hundreds of fertilizers trials with foliar, root, drain water and soil analysis, for Phalaenopsis, mottled leaf Paphs, strap leaf ones, even cuthbertsonii, cymbidiums, and many others. Different media, sphagnum buffered sphagnum oxygrow, bark mixes, rockwool... We even went to the lenght to use radiolabeled nitrogen sources at a point, and eventually proved that some orchids are fully unable to use nitrate efficiently as a nitrogen source...

Hi Roth,
Wow, that’s a lot of plants. Please confirm that you are saying that if we see similar issues with multi-floral paphs, it is probably (in the first instance) a nutritional deficiency that might be addressable by using a fertilizer with a nitrogen source of urea, instead of just MSU. I presume (probably a mistake) that rotating this in to my feeding regiment would work. Does this strategy differ based on sphagnum versus bark mix? ( I start all of my flasklings out in spagnum, but eventually move some of my more mature plants out to bark mix.)
Obviously if it progresses to bacterial rot, that’s another story. Thank you.

 

[Ray]

That's for sure a potassium deficiency, and we studied Phragmipedium as a pot plant. it can be a direct one by lack of potassium, or an indirect one if the pH is too low or swinging too much. Urea helps as well to balance the plant growth, as nitrate is a poor source of nitrogen for quite a few species of Paphs and Phrags...

			N	K	Ca	Mg
Phrag 17-1 Perfect	ppm		13734​	17706​	8560​	2430​
Phrag 17-1 Brown tips	ppm		11830​	3537.3​	33960​	3863.7​

There are rows and rows like that in my database, and brown tips for Phrags = potassium deficiency. then I can say it is a potassium deficiency... Note that Ca and Mg can be toxic and block the potassium, if they are supplemented with a fertilizer containing nitrates...

That "note" was precisely what I was going to point out. N, K, Ca, & Mg can compete for sites in the plant chemistry. I certainly cannot argue with field data, but what I wonder is if the symptoms originate directly from a K deficiency as much as a Ca/Mg "toxicity"? One could argue that the symptoms correlate with either low-K or high-Ca, and the data does not confirm causation. Your "K deficiency" assessment might be dead on, or maybe not.

Are those numbers from dry tissue analysis? If so, they are a great deal higher than what I've read for wild-collected samples, which would make me wonder if they were overfed.

I feed my plants a regular regimen (100 ppm N weekly) using K-Lite as the only fertilizer. It is 12.9% N (12.3% nitrate, 0.6% ammoniacal) -1.3% K2O-1.3% P2O5-10% Ca-3% Mg. My tap water supply is almost pure, and has had about 50 ppm Ca added. I have not seen such leaf tip issues, despite the fact that the N is almost all nitrate and my Ca:K ratio is pretty much the same as your "brown tips" example.

As to the MSU publications, I don't know if I'd call it "voodoo", but the formulator has told me "we tried it and it worked." I don't think there's anything magic about the formula, but it was the first fertilizer marketed for orchids that contained calcium, which may seem simple, but was a nutritional "breakthrough" in educating growers about the need.

I would be more inclined to agree that K-Lite might be more "voodoo-like", but only as it originated with the serendipitous collaboration of a ceramist aware of the negative effects of K on the stability and durability of glass and ceramic bodies, and a microbiologist studying toxicity in fresh water mollusks that had shown K to be toxic, especially if Ca was deficient. Those facts soon became "what about K in plants?" and there was a new formulation born. Once again, the "we tried it and it worked" conclusion was met. Since then, digging in the literature has turned out to back up the concept through analyses of the solutions to which wild plants are exposed and their tissue analyses.

 

[SelectOrchids]

That "note" was precisely what I was going to point out. N, K, Ca, & Mg can compete for sites in the plant chemistry. I certainly cannot argue with field data, but what I wonder is if the symptoms originate directly from a K deficiency as much as a Ca/Mg "toxicity"? One could argue that the symptoms correlate with either low-K or high-Ca, and the data does not confirm causation. Your "K deficiency" assessment might be dead on, or maybe not.

Are those numbers from dry tissue analysis? If so, they are a great deal higher than what I've read for wild-collected samples, which would make me wonder if they were overfed.

I feed my plants a regular regimen (100 ppm N weekly) using K-Lite as the only fertilizer. It is 12.9% N (12.3% nitrate, 0.6% ammoniacal) -1.3% K2O-1.3% P2O5-10% Ca-3% Mg. My tap water supply is almost pure, and has had about 50 ppm Ca added. I have not seen such leaf tip issues, despite the fact that the N is almost all nitrate and my Ca:K ratio is pretty much the same as your "brown tips" example.

As to the MSU publications, I don't know if I'd call it "voodoo", but the formulator has told me "we tried it and it worked." I don't think there's anything magic about the formula, but it was the first fertilizer marketed for orchids that contained calcium, which may seem simple, but was a nutritional "breakthrough" in educating growers about the need.

I would be more inclined to agree that K-Lite might be more "voodoo-like", but only as it originated with the serendipitous collaboration of a ceramist aware of the negative effects of K on the stability and durability of glass and ceramic bodies, and a microbiologist studying toxicity in fresh water mollusks that had shown K to be toxic, especially if Ca was deficient. Those facts soon became "what about K in plants?" and there was a new formulation born. Once again, the "we tried it and it worked" conclusion was met. Since then, digging in the literature has turned out to back up the concept through analyses of the solutions to which wild plants are exposed and their tissue analyses.

The numbers are indeed from dry leaf analysis, and I do have as well in the database 'quite a few' samples from wild plants and leaves, of genera that we are concerned with...

The people who publish analysis in research are usually amateurs, at best, and that's why too there can be weird results. You need to sample a fixed leaf, of a fixed age ( like the 2nd mature leaf from the top of a Phalaenopsis, or the new fully expanded leaf on a Cattleya, or the one expanding at the same size as the sheat...) and strictly do the same for all the research. If you take a spent leaf, or the leaf at the wrong season in the wild, the results vary very, very wildly.

There are protocols in horticulture and agriculture, which leaf, what age, what protocols exactly for the analysis, etc... and in many studies I see antique, imprecise protocols for analysis as well... Usually the best is to use an ISO certified lab, with all protocols that are normalized...

But for those figures, they are really normal for even wild plants...

As for the potassium deficiency, it depends as well on how much stress the plants have, if they are grown slowly compared to their normal speed, etc... then they have time to accumulate and move onwards. If the plants are grown optimally, or even with supplemental light ( and that would depend on the spectrum of the light, the varieties, etc...), then deficiencies can be very fast to appear.

If we take the rothschildianum as an example, in the wild when a growth is blooming, it already has a near mature growth or two new growths, and new growths already formed on those new growths. Hence, yearly blooming, if not faster. I saw them myself, and that's what I noticed. So when people are blooming a single growth + a smaller new one, something is wrong, and the plants are not optimally grown...


https://pbase.com/rogiervanvugt/image/142283210
Phrag kovachii, we see a lot of wild plants sold in the US and Europe, and they have mature, near mature, newer, and smaller growths in many cases. Anything that does not have a NBS growth on the blooming growth, and a new one on the NBS one is not properly grown for the species... etc...

I call MSU Voodoo, for a good couple of reasons:
- They tested the well water formulation, and calculated the RO water by using only nitrates...
- They did not do any analysis to prove that the formulation is superior.

At a point, putting ice cubes at the base of a Phalaenopsis will induce a spike, so 'we tried and it works', but is it a really good solution, after all?

The MSU 'pure water', 'all nitrate' was in fact a big step backwards compared to the urea/etc... based fertilizers that were used before. A lot of plants have a yellowish, chlorotic cast, and they are not as dark green and healthy as they used to be 20-30 years ago... It can work in some conditions, but it is very far from optimal.

The K-Lite is not supported by the data of most of the commercial nurseries, on the opposite in fact.... When a plant drains 30% of the potassium of the leaves at the time of its blooming, it is obvious that the plant needs more potassium...

Fresh water mollusks can be nice, but they have nothing to do with us. If you take another example you can kill cows with Molybdenum. Doses that we would easily take without any problems... Or some plants need toxic levels of boron to grow compared to others. What goes for an African Adenia will kill a pelargonium in days.

What would have been a good case would be, use it for a year or so, test with a normal K feeding, with adjusted pH for both groups, and make leaf analysis as well as soil analysis. Then it is possible to give advice. Otherwise, indeed it is more hearsays, anecdotical and voodoo...

 

[Ray]

I certainly will defer to your knowledge in the subject area, but please understand that I frequently challenge "known" or "well-established" informations, seeking to understand the science behind it and have turned up a lot of fallacies over the years, but my own observations are pretty keen and I have a hard time being convinced that something "is wrong" when it works for a lot of growers.

 

[SelectOrchids]

I certainly will defer to your knowledge in the subject area, but please understand that I frequently challenge "known" or "well-established" informations, seeking to understand the science behind it and have turned up a lot of fallacies over the years, but my own observations are pretty keen and I have a hard time being convinced that something "is wrong" when it works for a lot of growers.

That's the problem too, to understand the science behind, you need to have foliar mineral analysis etc... and study all the parameters.

The problem is that it does not work for a lot of growers. Actually I helped one very famous grower to recover from a collection that was nearly destroyed by the MSU fertilizer nitrate only, 2 years ago. It was one of the most important collections of species orchids in the US.

MSU Well Water would be a better choice, due to the presence of ammonium in the blend, though it is not optimal.

When I see as well the plant quality by many 'professionals' I am shocked. The mantra is that 'is there any proof that dark green leaves are healthy plants', then they pass chlorotic things that grow at a snail pace as 'well grown' too... I won't name many of them, but it is a fact...

But yellow Paphiopedilum seedlings is not something normal, as an example. Or chlorotic cattleyas with yellow leaves 'because of the light'... and those are commonly sold...

 

[Ray]

You know, it's funny... I hear about feeding regimens that vary all over the map, and the growers all seem to be more-or-less successful. I know a grower near me here in NC who feeds only calcium nitrate and Epsom salts, plus Kelpak and Quantum supplements, with one dose of Miracle-Grow 15-30-15 a year for trace elements. His plants look and bloom great.

I think that if one focuses too much on "fertilizer" and not enough on the other aspects of good culture, it's easy to screw things up.

 

[wongwong]

That's for sure a potassium deficiency, and we studied Phragmipedium as a pot plant. it can be a direct one by lack of potassium, or an indirect one if the pH is too low or swinging too much. Urea helps as well to balance the plant growth, as nitrate is a poor source of nitrogen for quite a few species of Paphs and Phrags...

			N	K	Ca	Mg
Phrag 17-1 Perfect	ppm		13734​	17706​	8560​	2430​
Phrag 17-1 Brown tips	ppm		11830​	3537.3​	33960​	3863.7​

There are rows and rows like that in my database, and brown tips for Phrags = potassium deficiency. then I can say it is a potassium deficiency... Note that Ca and Mg can be toxic and block the potassium, if they are supplemented with a fertilizer containing nitrates...

Nutrient deficiencies can appear on multifloral Paphs as well as a 'bacterial rot', water soaked blotches that becomes brown and progress very quickly... A multifloral Paph will use about 30% of his potassium storage to make the flower spike and bloom. Once it fades, that amount is gone from the leaves.

On Phalaenopsis, the plants become yellow when they bloom, and it can happen over 1-2 weeks, the plant can lose nearly all of its leaves in such a short time, and it looks like bacteria. Those are extreme cases, but I saw them several times at several pot plant growers.

One problem with published papers about plant nutrition in the orchid world is that they are done voodoo style.... MSU or K-Lite were written as an example without any support. The use of nitrate only as a nitrogen source for orchids, that urea is not used by plants, etc... are as well voodoo quack science.

I gave an example before. Nitrate as a sole nitrogen source is better than urea when you use sphagnum without buffering or keeping the pH in check. But it is not the best nitrogen source. However, the problem is a too acid potting mix, and nitrate help the plants to suffer less. It is not that nitrate is better than urea or ammonium.

My experience comes from the management of millions of plants ( not exaggerating...), a dozen pot plant customers, including the 5 largest Phal growers in the world, expert for some of the largest orchid labs known, and hundreds of fertilizers trials with foliar, root, drain water and soil analysis, for Phalaenopsis, mottled leaf Paphs, strap leaf ones, even cuthbertsonii, cymbidiums, and many others. Different media, sphagnum buffered sphagnum oxygrow, bark mixes, rockwool... We even went to the lenght to use radiolabeled nitrogen sources at a point, and eventually proved that some orchids are fully unable to use nitrate efficiently as a nitrogen source...

Do the nitrate-reduction (alkalinity generation) intensify K exhaustion in old leaf?
Do nitrate lever Ca2+ influx?
(get a quick search on "Ecology of Paphiopedilum rothschildianum at the type locality in Kinabalu Park (Sabah, Malaysia)"some data Ca:K mostly goes to ~1:1)

add a high K fertilizer with urea

At what ppm K is considered as “high”?

Nitrate as a sole nitrogen source is better than urea when you use sphagnum without buffering or keeping the pH in check. But it is not the best nitrogen source. However, the problem is a too acid potting mix, and nitrate help the plants to suffer less. It is not that nitrate is better than urea or ammonium.

Is it possible to keep sth. in acidic sphagnum moss system with low nitrate (ratio)?
(If phal in sph. moss defines 90% of market …… what tells make sense or not)

The demand for higher B ; Mo; Mn/Fe ratio…. Are they co-related with calcerous origin? Or in quite district-specific manner?