Complete root ball rot

Discussion in 'Slipper Orchid Culture' started by Dung Lung, May 7, 2017.

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  1. May 7, 2017 #1

    Dung Lung

    Dung Lung

    Dung Lung

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    I believe many of you must have experienced root ball rots as a whole. Many of the dark and dead roots, when squeezed, burst with toxic liquid, indicating that they rot just recently. The whole thing rots simultaneously!
    If the medium is too wet and soaky, the root ball would not have developed! Therefore, there is nothing wrong with the potting material!
    What went wrong!
    One might think it was because of the medium decomposition, but rejected because records of years without repotting but with healthy plants were common!

    I think what actually happened was:
    Right after repotting, the plant grows happily with new roots. This roots fills up the void in the new medium. Thus, the originally air sufficient material, together with the many roots, becomes a soaked block. If watering frequency is not reduced, or the temporature increases(which is natural if repotting in spring), the waterlogged medium would cause root rot. As a result, the whole root ball fails!
    To overcome the problem, I use coarse materials. Mist daily, particularly the underside of the leaves., lengthen the watering cycle but with plenty of water, eg once every 6,7days, good air circulation of course. Replace the top material by inorganic material after the root has established. By then, the rate of root dying would reduce. Toxic liquid generated by individual dead root could easily be drained away, leaving sufficient voids to be replaced by new root later.

    Your comments please.
     
  2. May 7, 2017 #2

    troy

    troy

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    no hatred!!
    Need a picture to see
     
  3. May 7, 2017 #3

    gonewild

    gonewild

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    Soil born fungi, maybe Fusarium.

    Can be caused from the waterlogged conditions you describe. But can also attack the roots when the pathogen is present in the substrate. The pathogen can come with new substrate that is not sterile.
     
  4. May 8, 2017 #4

    NYEric

    NYEric

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    It's possible. 90% of plants I lose can be caused by media breakdown.
     
  5. May 8, 2017 #5

    Stone

    Stone

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    I think your reasoning is good DL but there may be other things to consider.
    If you are growing in conditions which have a cold period, the plant may have become dormant and watering at this time will rot the roots immediately. After some time, certain nutrients can become depleted if not replaced. For example, if you use rain water or very pure water, you can run short of calcium and boron which will also cause the roots to stop growing and eventually die. Depending on the p/mix, when it breaks down it can become very acidic or toxic for some reason and this can also take the roots with it. But yes when the pot is completely full of roots, air circulation drops dramatically and will cause trouble when you water.
     
  6. May 8, 2017 #6

    Dung Lung

    Dung Lung

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    Yes, everything adds.
    For information, i grow at the roof. Summer temperature could be as high as 40 degrees C, ie 104 degrees F !
     
  7. May 8, 2017 #7

    Lance Birk

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    First of all you are watering the plant way too much; ambient humidity in HK is more than sufficient for you to forego watering for weeks although I do not recommend that. I visited a grower there who grew his paphs on slabs and they were very healthy.

    Secondly, is there any artificial air circulation around your orchids? They should be getting plenty.

    You didn't say if this plant was a hybrid or a species. If a species it sounds like a mycorrhiza attack, nothing you can do about that.
     
  8. May 8, 2017 #8

    gonewild

    gonewild

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    Mycorrhiza attack?
    Mycorrhiza is a symbiotic relationship between plant and fungi. Symbiotic is beneficial not detrimental.
    Do you mean attack by pathogenic fungi?
     
  9. May 8, 2017 #9

    Lance Birk

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    Orchid mycorrhizae work both ways; sometimes it's the fungus that kills the 'host' rather than vice versa.
     
  10. May 8, 2017 #10

    orcoholic

    orcoholic

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    It's my experience that when the roots fill the pot and all the air spaces, no water can even get into the pot. The roots in the pot stay viable, white and hard, but they get very dry with no growing tips. They can be soaked in water and become okay roots again.

    From the info provided, my guess would be the orchids (with the entire root balls rotting) were over-potted and then watered too often. That's a sure fire formula for rotting all the roots.

    If the pot is completely packed with roots and medium, where is water going to get in and subsequently rot the roots?

    As far as the records indicating some of the orchids went years without repotting and still have good roots I have no idea, unless there were roots growing outside the pots that were nourishing the plants.

    This happens a lot to orchids that aren't repotted enough. It doesn't mean the potting medium was still good. I've repotted a lot of orchids with healthy roots outside the pot and dead roots inside (because the medium got too old to support good root growth.)

    Also, the mix may have been made up of medium that doesn't break down.
     
  11. May 9, 2017 #11

    Dung Lung

    Dung Lung

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    Stone

    The earth is heating up, low temperature is no more a problem nowadays!
     
  12. May 9, 2017 #12

    Dung Lung

    Dung Lung

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    Orcoholic
    You have the point: overwatering (together with panthogen), explains the simultanous complete rot.
    For this reason, I lengthen the watering period.
    However, I am forced into a dilemma: summer heat cause the plant dries so quickly that I have to water frequently!
    I would like to share with you guys: I mist the plants daily(more than once), particalarly the underside of the leaves (good air circulation).
    I am glad to inform you that they get through the summer heat, one leaf larger than the other. What is more, the death rate reduces remarkably. The only drawback is, new growths should be dried after misting, because they are more liable to rot if water stays at the centre.
    It appears that not only the roots, but the leaves play an important part in moisture absorption.
     
  13. May 9, 2017 #13

    Dung Lung

    Dung Lung

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    Orcoholic
    You have the point: overwatering (together with panthogen), explains the simultanous complete rot.
    For this reason, I lengthen the watering period.
    However, I am forced into a dilemma: summer heat cause the plant dries so quickly that I have to water frequently!
    I would like to share with you guys: I mist the plants daily(more than once), particalarly the underside of the leaves (good air circulation).
    I am glad to inform you that they get through the summer heat, one leaf larger than the other. What is more, the death rate reduces remarkably. The only drawback is, new growths should be dried after misting, because they are more liable to rot if water stays at the centre.
    It appears that not only the roots, but the leaves play an important part in moisture absorption.
     
  14. May 9, 2017 #14

    orcoholic

    orcoholic

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    Misting will help reduce the need to water as the orchids won't need to take as much water up through the roots to keep them cool.

    Misting is okay as long as the plants are dry by nightfall and the plants aren't showing any rot, etc. Water on the leaves, or in the pots, combined with high temps is a perfect environment for pathogens to develop.

    Lengthening the amount of time between waterings is a good idea as long as the orchids don't show any stress. Dry roots don't rot.
     
  15. May 9, 2017 #15

    gonewild

    gonewild

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    Mist with less water. Proper misting does not result in water in the crown. Use finer mist, shorter duration and more frequent intervals. When leaves are hot they do not absorb very much water. The purpose of the mist is to cool the leaf temperature by evaporation.


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