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Masdevallia Bennettii yellowing/dropping leafs

Discussion in 'Issues, Disease and Pests' started by PhatInferno, Nov 28, 2023.

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  1. PhatInferno

    PhatInferno New Member

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    Hello! my bennettii here has started to get this yellowing on his leafs, as well as just dropping two leafs recently... was hoping that it was just affecting the older leafs, and the newer ones would be safe, but the newer leaf also started getting the yellowing. looking for advice on what to do!


    I kinda think that he might have been over watered/under watered and need to remount him, but he also putting out a ton of roots...and figured id ask first before committing ( also would winter be ok to remount him in?)

    -in a case that is >75% humidity with temps from ~62f - 70s now in the winter was getting to ~80 in the summer
    -watered ~once daily when hes almost dry
    -received 5 months ago, and had to switch cases 2 times (one was being built) so not too surprised that he is also stressed

    the other minis in my case seem to be fine, only him thats doing this!
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  2. Raven

    Raven Well-Known Member

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    How do you fertilize? Also, how much light does it get?
     
  3. PhatInferno

    PhatInferno New Member

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    1/4 strength MSU once a week, and currently under some t5 lights for 10 hrs now at around 3k LUX/280 FC ( or about 2 ft below the lights)

    have been thinking of getting some seaweed stuff soon as well..
     
    Last edited: Dec 2, 2023
  4. Arne

    Arne Active Member

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    Just by the look of the leaves I would guess too much light. I have the same problem but in my case it actually seems to be the result of salt build up.
     
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  5. PhatInferno

    PhatInferno New Member

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    cool ill try lowering her and see if the newer leafs recover!
    and i know i still gotta remount eventually, whats the best season to remount in? assuming spring/summer when its warming back up?
     
  6. Arne

    Arne Active Member

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    I will only remount when I know a bunch of new roots are coming regardless of season. Remounting scares me every time actually. But do you need to remount this one really?
     
  7. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    How long has it been on the mount and is the mount rotten? The roots I can see look alive and appear to have green root tips. Rather than remounting, you might get rid of the fern so the fertilizer you are applying is not used by the fern, but is more available to the orchid.
     
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  8. Raven

    Raven Well-Known Member

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    You might wanna try a different fertilizer too. MSU has a great formula and works well for the majority of epiphytic orchids. Unfortunately, a lot of MSU that is offered for sale online is a repackaged one. And nobody knows what proportion of its components ends up in different package. A few years ago I’ve had an issue when my orchids would slowest decline for no obvious reason. They would produce smaller leaves, they would rot easily, they would never flower. As soon as I switched a fertilizer they started recovering. Another thing with MSU is that when repackaged improperly it can lower down the the PH by a lot, making your fertilizer solution very acidic.
     
  9. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    I had the same experience with MSU starting with a batch I bought in the summer of 2019. It devastated my collection. Some of the plants didn't seem bothered at all, but the majority suffered, rarely bloomed and had deformed flowers when they did bloom. I still have some lingering symptoms on some of the soft leaved plants. The leave do not open normally, but get stuck together the length of the leaf or unable to emerge normally.
     
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  10. Arne

    Arne Active Member

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    This is concerning because I think this might happen to any fertilizer. I noticed when I shake the container with the solid, the particles separate easily in to layers of different sizes.
     
  11. Ray

    Ray Orchid Iconoclast Supporting Member

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    Greencare, the manufacturer of MSU fertilizers and K-Lite, primarily cater to large-scale operations that would be more likely to use several full bags of fertilizer at a time, not portions of one, so getting a homogeneous blend of components is normally not a huge concern.

    They are also dealing with raw materials availability and pricing variations that lead to changes in the appearance of the blends from manufacturing batch to batch. (The current K-Lite batch I’ve been repackaging is very homogeneous.)

    There are two things that can reduce folks’ concerns: for one, don’t try to measure your granulated product for per-gallon mixing. Instead, make a concentrated solution from a larger portion of the solid blend and dilute some of that for final application. One pound of MSU RO or K-Lite diluted to one gallon of total volume, for example, will give you a concentrate that can be diluted 1 ounce per gallon to make a 125 ppm N solution for use. (They are 13.2% and 12.9% N, respectively, so the final concentrations will be similar.)

    Second is the fact that most nutrients aren’t “single, immediate use” chemicals. Nitrogen is the important one, and that is what should be used as the feeding control factor. With the exception of calcium, all the other elements are generally overstocked and/or recycled within the plant and can be relocated to newly-growing tissues as needed.

    P & K, for example, are stored to excess in plants, so if you don’t apply it at all for a while, the plant will still have plenty. One botanical garden orchid grower I’m aware of primarily feeds calcium nitrate solutions most of the time, adding other elements quarterly, and it’s common for large-scale nurseries to feed NPK all year, adding trace elements once annually - and that’s for plants that grow much faster that any orchid.

    The bottom line is that “meal to meal” nutrient variation isn’t much a concern, and can be easily mitigated.
     
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  12. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    Rays comments are valid, but of no help in my case. I was buying my MSU RO in 50 lb batches (2 25 lb bags at a time). I mixed up 15 gallons of concentrate for 100::1 use in an injector pump. I had been using it for over 15 years and was very happy with it. Then I bought a the new batch in 2019. Most genera in my collection started to decline and a few seemed perfectly happy. That went on for well over a year. I kept checking the water, pH, TDS concentrations, etc. I had deformed growths, deformed flowers, no root growth, algae on everything and almost no blooms. I feel really stupid now, but it never occurred to me that it was the MSU. I finally was advised by a consultant to switch to a high nitrogen regime. The difference was amazing and immediate. Two weeks after I switched I started to see lots of root growth. Some plants continue to decline and die and it seems that some will never recover. It has taken a long time, but I now see healthy plants and blooms that I haven't seen for years.

    I now rotate between 2 fertilizers and MSU isn't one of them.
     
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  13. Raven

    Raven Well-Known Member

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    I have to add that mine was MSU K-Lite and the outcome was very similar to Marni's. I lost about 20% of my collection because of this.
     
  14. PhatInferno

    PhatInferno New Member

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    again i got it ~5 months ago but didnt remount it when i got it, was my first mini and i have researched and remounted all my newer minis when received since then, but didnt get to remounting her yet ( and she was doing fine up untill ~month ago).
    i dont think the mount is rotten, but was considering it with how the moss looks/ and the fern getting quite big on it.... but again a bit nervous with how stressed it currently is

    i got my fert from my local orchid society's booth, what other ferts would you use/suggest?

    with my masdevallia, this is currently the only one that seems to be having issues for me, some bulbos that i got around the same time as the masdevallia appear to be fine. my Lepenthes ( just bloomed too!), dracula and Scaphosepalum have yet to show similar signs, though they are a bit newer (received 2.5 months ago).
     
  15. Ray

    Ray Orchid Iconoclast Supporting Member

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    i’m certainly not going to argue with your observations, but from a scientific perspective, I have a hard time accepting that a particular formula or brand of fertilizer will be “night and day” better or worse than another.

    The raw materials used to produce water-soluble fertilizers are pretty much the same no matter the brand or formula. That makes me think that something else fertilizer-related is the true issue.

    Ruling out this being a “Benlate-like” issue (Benlate was a fungicide commonly used on orchids for years, then it wiped out millions of dollars worth of orchids. It turned out that it had been a batch contaminated with a herbicide, but there are still folks who blame it on the Benlate) it sounds like something else is the true issue.

    Marni commented that a consultant recommended a “high nitrogen” formula. That begs the question of “was that by content or by ratio?”. A 30-10-10 certainly has the highest nitrogen content, but K-Lite, at 12-1-1, is the highest nitrogen ratio, complete fertilizer available, yet Raven felt there was an issue with it. Feeding should be controlled by nitrogen concentration and feeding frequency. If you have been using “x” amount of the 30-10-10, you’d need to use “2.5x“ of the K-Lite for the same dosage.

    There was mention about controlling the concentration by checking the TDS, and that immediately raises a big red flag for me, as TDS meters are notoriously inaccurate.

    A TDS meter is just a (usually cheap) electrical conductivity (EC) meter with a built in conversion factor (usually based upon NaCl) to display TDS. The problem with that is that the EC of a solution varies not only with the concentration, but with the chemical makeup and ratios of the solution, so each fertilizer should have its own conversion factor, and the meters don’t do that.

    Many years ago, I measured the TDS of a 100 ppm N MSURO (13.2% N) solution in RO water with two TDS meters. One said the TDS was about 375 ppm, while the other said about 500. The true TDS of that solution is 740 ppm. For reference, a 100 ppm N solution of K-Lite (12.9% N) is 770 ppm TDS. Had I been controlling based upon the first meter, I would have been underfeeding by 50%, and that certainly could lead to long-term starvation.
     
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  16. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    I find that calibrating the meters before using them gives better readings. Of course if your meter is defective, calibration won't help.
     
  17. Ray

    Ray Orchid Iconoclast Supporting Member

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    That more or less what I did - it’s not calibration, per se, but knowing that the true TDS is 740/500=1.48x the reading makes it easier.

    I still think it’s best to focus on the mass of nitrogen applied through calculation and dilution.
     
  18. W. Malewa

    W. Malewa Active Member

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    New roots look very impressive, it is nearly as if the leaves are drained for root growth. The plant went at one stage from low light to higher light? I also would not entertain ferns, they speed up the break down of timber mounts.
     
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  19. PhatInferno

    PhatInferno New Member

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    only a slightly higher light, maybe like +500 LUX and 1 hour less than the lights it was under originally.. thats also why im kinda guessing that maybe a section or larger root rotted, causing the plant to die back a bit? with him pushing out alot of roots to make up for it, though maybe id still see signs of rot if it were the case...idk lol.

    this is him currently, i only moved him a little bit lower nothing else. Newer leafs (+4!) are smaller but so far shows no signs of yellowing yet which is a good sign! roots are still going as well, and so far other older leafs have yet to drop.
    seems to be maybe getting a bit better!
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    3.jpg 5.jpg 2.jpg
     
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  20. W. Malewa

    W. Malewa Active Member

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    It looks as if your M bennettii turned the corner, and maybe part of the yellowing had to do with climate change, relocating. The mount is holding up fine.
     
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