Miltoniopsis Leaves Yellowing After Repot

[scy]

I noticed new growth coming from my miltoniopsis and decided now would be the best time to repot, since it was tightly packed in an unknown medium. (I received it as a gift for Christmas.) When I took it out of its pot, I saw that the previous medium was small bark chips and sphag. The medium JUST started to decompose and the roots were beautiful and in great shape!

I soaked small bark chips in water overnight and then sprayed with rubbing alcohol to kill off any bacteria before potting it up. I teased it around the roots and gently tapped it down to make sure it was firmly potted. I watered it with the recommended dilution of KLN solution (1/4 tsp per liter of water). Using a wooden skewer to help me determine when the medium has dried out, it was bone dry half a week later. I rewatered using the same solution and now I noticed that 2 of the outer leaves have turned yellow.

Is potting medium of only small bark chips sufficient or should I add some PrimeAgra in the mix as well? Is this due to the KLN solution or something else I did? I plan on just flushing it out and watering with regular water on future waterings. Is there anything else I can do to help it now? Thanks in advance for the advice!

[silken]

The yellow leaves do look like the oldest leaves. They will turn yellow and die at some point. It looks like there is lots of healthy green growth and no pleated leaves. The roots look great.

One thing you mentioned is that the new bark got bone dry. Miltoniopsis don't like to be bone dry. So between re-potting and it getting too dry, that may have induced the oldest leaves to die off. I usually grow mine in mostly sphagnum moss with a bit of perlite, bark and charcoal mixed in. Several orchid suppliers say theirs thrive in moss so that is why I chose it. Milts like to always be partially moist so bark alone may be hard to achieve that. New bark doesn't absorb water as well for a month or so either. I use K-L-N on mine with no problems.

You mentioned you treated the bark with rubbing alcohol. If it didn't evaporate or get rinsed off before potting that may have burned the roots a bit too.

[King_of_orchid_growing:)]

I wouldn't worry about the yellowing, those are old leaves and would've fallen off anyways. It's of little consequence in the long run.

I have mine potted in small bark chips only. I water a bit more often, but it gets the job done, and the roots are beautiful, especially when they're in active growth.

[scy]

The yellow leaves are the oldest leaves. The reason why I was concerned was because it was still green like the others before I repotted. They turned yellow at such a fast rate (first one turned yellow a few days after the repot and the 2nd one is almost all yellow as of yesterday). I thought when older leaves turn yellow, it's more of a gradual process. I remember reading somewhere that after a repot, I should not water again until it was dry, because roots need a chance to heal and have trouble doing so when wet. Should I just disregard that and water when slightly damp?

I have tried to use sphag in the past but it always led to root rot since the sphag never seems to dry out in my growing conditions. I noticed that the bark is drying out rather fast (3 days?) but that may be because it's new bark.

Would it help if I repotted it and added PrimeAgra to the mix? Or should I put this plastic pot inside a clay pot and fill the sides with PrimeAgra to help seal in some moisture? It was previously potted this way except with large pieces of bark. Should I keep watering with KLN solution until I see root growth or just switch back to water now?

[King_of_orchid_growing:)]

Originally Posted by scy

The yellow leaves are the oldest leaves. The reason why I was concerned was because it was still green like the others before I repotted. They turned yellow at such a fast rate (first one turned yellow a few days after the repot and the 2nd one is almost all yellow as of yesterday). I thought when older leaves turn yellow, it's more of a gradual process.

It can be. But at the same time those are really old leaves you're talking about. Those leaves were there during the formation of the shoot. Eventually you're only gonna end up with the 2 leaves underneath the pseudobulbs and the one(s) on top of the pb's.

Originally Posted by scy

I remember reading somewhere that after a repot, I should not water again until it was dry, because roots need a chance to heal and have trouble doing so when wet. Should I just disregard that and water when slightly damp?

I haven't heard of this claim, so I can't verify or deny its validity.

However, when I first received my Mltnps, I did repot it, and I watered it like it had been growing in my collection for years. It still grew.

It's up to you to decide which course of action to take.

Originally Posted by scy

I noticed that the bark is drying out rather fast (3 days?) but that may be because it's new bark.

That's actually drying out a lot slower than mine. Mine can dry out the same day; and my plant's not dying.

Originally Posted by scy

Would it help if I repotted it and added PrimeAgra to the mix? Or should I put this plastic pot inside a clay pot and fill the sides with PrimeAgra to help seal in some moisture? It was previously potted this way except with large pieces of bark. Should I keep watering with KLN solution until I see root growth or just switch back to water now?

I don't think all these extra precautions are necessary, it may create other unforeseen problems to solve.

I still to this day do not see a positive significant difference between using and not using rooting products such as KLN or Superthrive and cannot say anything in this regard. So my personal advice is, go ahead and just use plain good old water.

[scy]

Thanks for the advice everyone! I'll just water it as normal and will keep you posted of any changes.