Lost one and what about this other?

[risa59]

I went to our local Orchid Society sale a few weeks ago and bought 2 Phals and two oncidiums plus lots of supplies. This morning, one of the Phals dropped all of its leaves! I hadn't watered it since the Sale since it still seemed wet . Sure enough it was root rot Oh well.
My question is about one of the oncidium: MKO 1886 Dgmra, Tropic Splendor X Oda. Nichirei Liliac. It is a lovely and large plant in flower from one large spike. But this morning, I noticed that one of its leaves is yellowing from the leaf vein outwards. Normal? Root problems? Not likely too much light since we are not getting much this time of year around here (but I am using a grow light). Thanks for the help.

[jbigio]

I find that its fairly normal for a leaf to turn now and them as long as its not a group of leaves one after the other. I would pull the plant out and check the roots. I have done this to a lot of plants in bloom with little problems. If the roots look good just put it back and keep an eye on it. If the root are bad trim the dead roots and re pot in fresh mix. Better to lose a bloom then a plant
hope it helps
Joe

[articuno75]

Hi Risa

I was looking at the dead center of the plant and it has me a little concerned. I see a Psbulb that looks brown. The mushy brown. Is it like that? and is this leaf connected to it?

No I don't think too much light either. If it were, the other more outer leaves would show signs first, not the center most part of the plant.

This looks like a fungal issue. Can you take a more detailed pic of the psbulbs? It could be something entirely different, but need a closer inspection of the plant.

[patticake]

This one looks a little shriveled. It can take more water and light than a Phal can. It looks like it's in a bark mix. I use a spray bottle to water mine, that way you can get a nice even watering. Was the Phal in sphagnum moss? Cool temps with that wet moss, will cause disaster every time. Good luck...keep us posted.

[Hummer344]

My first thought was that, since the phal hadn't been watered in awhile, what was it planted in. Probably sphag. I would check the rest and, if they are potted in sphag, I would re-pot them. Losing a leaf or two wouldn't bother me but I would keep an eye on it. I don't see the musshy pb that Jenny is refering to but if it is mushy I would cut it out ASAP

[cassier]

I'm with Jenny, is the leaf that is yellowing connected to the brown pb? If so that can indicate rot. Can you post us a closer look of the pseudobulbs.

[risa59]

Checked out the oncidium. Cut off the yellowed leaf. Nothing mushy and nothing brown. Roots looked good (white roots on top and brown roots down below is OK in oncidiums right?). And since I had the potting stuff out anyway, I took your suggestions and repotted 2 more of my phals in bark, since I hate how wet that sphag. moss stays here in my environment.

No the phal I lost after only two weeks was in bark. But it was soaked, I guess.
Now for my dumb question: what is the purpose of the potting stuff we use for the orchids? I told you this was dumb! I assume it only provides a place to anchor the orchid, allows air to flow around the roots and brings moisture to the roots. But do the bark or moss provide any nutrition for the orchid at all? Thanks to all for your suggestions.

[jerrymeola]

Risa

your idea of medium is basically correct.

The medium is to allow a plant to grow in a pot with conditions as near as possible to growing naturally bare root on a branch.

That means lots of air circulation over the roots and the ability to dry naturally.

It will retain moisture around the root area, more so than naturally growing on a branch. But this is OK since we do not have the constant humidity the plant would have normally. It creates a moister area around the roots.

That is why it is important not to let the medium decompose to where the medium packs down and shuts off the air.

I bet the Phal you lost had no air circulation through the medium from having been in the same medium too long. As the bark decomposes the smallest pieces flake off and pack down as if it was soil.

Theoretically the plant can get nutrients from the bark as it decomposes but I believe that by that point the decomposing bark does more harm than the minimal nutrients it gives the plant.

Feed regularly and anything extra it gets from the medium is a bonus.