Hello! I am a newcomer, hope this is the right place to ask this question! I am not very experienced with orchids or houseplants in general, but for a relatively new hobby it has brought me a lot of much-needed joy.

I found a gorgeous 'sharry baby' oncidium orchid at the supermarket. This particular individual had very plump pseudobulbs and radiated health. After her bloom, I pulled up the stake and noticed it smelled musty. I was concerned about mold and/or root rot, and decided to repot her despite being in the dead of winter.

I was not prepared for the absolute mass of fine white roots! They seemed happy and healthy. The media was fine bark with a bit of sphagnum moss. (Here is where I wish I had left well enough alone!) I had it in my mind to completely extract all of the old media. It took hours untangling the media from the roots, but the worst part was the coco plug. Right at the base of the main bulb in the center of the plant, stuck by countless roots in every direction, was what appeared to be a plug of very dense chocolate cake. I'd heard about the 'plug of death' many nurseries use to rear plants and knew that it could lead to future rot. So, I went to work picking the plug apart. By the end I was too exhausted to pot her back up, and I propped her upright with her roots (not bulbs) in a bowl of water. She drank a ton of water and stayed there for a few days before I mustered the courage to attempt a repot.

Roots, bulbs, and leaves all seemed in good shape despite the stress. The big challenge with repotting: there were so many fine roots I couldn't figure out how to integrate the bark into them in a way that wove them in so the plant would be supported. I used large orchid bark (all that was available) and a bit of sphagnum moss. There ended up being cavities and she wasn't well-supported (previously was totally stout) but I did my best with what was available. I ran lukewarm water through the pot (clear plastic with lots of drainage) for about 30 seconds every few days.

Her pseudobulbs quickly shriveled. I increased her watering by soaking her for a couple hours twice a week. The pseudobulbs have remained heavily wrinkled.

Is there anything I can do to restore my once radiant orchid? I am unsure whether I should repot her at the start of the growing season with finer bark, taking much more care to interweave and support her. I think many roots have probably died, which is why the long soaks haven't noticeably plumped her back up, and perhaps these should be removed.

Any guidance would be greatly appreciated! This plant is one that just spoke to my heart, I am very attached to it and would love to give the care that she deserves. I don't care about blooms, I just want her to be alive and well.

Thank you to anyone who took the time to read this lengthy question.

I only grow one Oncidium. You did make a mistake removing all the old media. It's best with orchids that have the thin numerous roots like Oncidiums to just shake off the media that the roots will let go of and leave it at that. The 'plug of death' does not apply to orchids. That refers to a tissue culture plant like an aroid. Tc plants sometimes have a synthetic media around the roots that is left on when they are potted up for sale by the grower. What you say was just likely decomposed bark at the very center of your rootmass.
Some orchids do not like to have their roots disturbed. Oncidium is probably one of these. I say probably because in nature many Oncidiums are lithophytes and epiphytes. The single species I have most commonly roots into rock crevices with no media at all. Just clings to the rocks. I put it in a wire basket 10 years ago with the roots hanging out and it's totally happy

I'm calling in an expert to help you, and would suggest you check out the Orchid Forum here. Lots of good knowledgeable people there
@Ursula

Stella38, all is not lost! Your Oncidium has just suffered a little set back that is all. It is fixable.
Orchids can be grown as houseplants but you can't treat them as such. As my good friend Gina said, they are epiphytes. Meaning they grow attached to something for support.
Those "tons of fine white roots" were happy and healthy. They needed a fine mix. What you used is too coarse, too open, keeping the roots too dry causing the bulbs to shrivel.
There are several vendors on line that sell fine orchid bark. That is what you need. Plus your chosen pot may be just a bit too big. You choose a pot in which the roots fit nicely in to. You do not choose a pot based upon the greenery.
Oncidiums are little " water hogs"! They like a fine mix and watered every three days or so.
No sun, just a bright windowsill. 65-82 degrees. Change the mix and it will quickly recover.

Thanks Nick..I tried to tag you but kept spelling your screen name wrong and getting other cat paws

Well, keep trying. As far as I know, cats only have 4 paws so sooner or later, you would find the right one.

my mistake strangely was not capitalizing the C

I happily echo your advice, Nick and Gina. Switch to finer bark and a smaller pot. Your plant will surely make it!

What a wonderful forum! Thank you all so much, I appreciate the great advice and kindness. I'm feeling much more hopeful knowing how to help. I also noticed today I think her newest pseudobulb has thickened up a bit and the leaves on that side look really happy, maybe the long soaks and grow light time have been doing something?

I chose the pot because it was 1-2 inches wider than the root ball (seriously, that thing was massive!) and I thought it would give her space to grow so I wouldn't have to stress her again with another repot so soon. Welp that backfired, time for another rescue mission! (But this time, a well-informed one. ;)) I'll have to order a smaller clear container along with the new bark. I'm looking at repotme's oncidium and seedling' imperial orchid mix, I have a mini phal that would probably appreciate a repot into finer bark as well, she's been very thirsty too.. live and learn!

Follow up questions,
1)I'm tempted to add a little bit of sphagnum or coco coir to the bark mix, yay or nay? (I feel like pure sphagnum always molds for me, even after I started soaking in hydrogen peroxide prior to use. maybe it's a bad batch)
2)how exactly do you recommend watering? Every 3 days sounds good, but would that be running water over the roots for an amount of time or soaking? I always use distilled.
3)I feel so bad for disrupting those beautiful roots, I imagine a fair amount have dried up or broken and are now dead. Best to clip these with sterilized shears, right? (I heard if they squish/outer layer pulls off they're goners)

Once again, I so appreciate the wonderful expert support of this kind community. Thank you! <3

p.s. @Gina1960 your oncidium and greenhouse are absolutely stunning! What a glorious beauty, roots just cascading out of the pot.. beautiful work!

Thank you stella! I'd like to grow more Oncidiums, I may get one when the Spring garden festival happens here is late March

Stella, soak it well and then let the Oncidium approach dryness, then soak again. There are so many variables in terms of growing orchids indoors and watering rates. Every home is different.
The warmer it is, the faster they dry out. The lower the humidity, the faster they dry out. I suggested every three days as a staring point. You do that for a few weeks and if the plant looks better, keep it up. If it doesn't look better, try every other day. It boils down to trial and error.
But I don't think it is a good idea ever to put any in a container with too much room figuring that it will grow into that pot. You are just asking for watering issues that way. You can't find the proper watering cycle between wet and dry.

Most orchids, including oncidiums, are epiphytic - they hang on trees and look like Gina's plant with roots hanging out everywhere. We humans live in a paradigm that says plants live in pots and we are determined to make orchids live in pots too. The only benefit to pots is to hold a little moisture against the roots. Epiphytes live in places with rain and humidity to keep the roots plump and happy. In the forest/jungle, the moisture is not held against the roots like a pot does and the roots dry a bit. Holding too much moisture causes rot because orchids would rather go commando and skip the pots.

The rule is the finer the roots, the finer the medium. I wouldn't add moss but would probably add some very chunky perlite. Most of my orchids have now gone commando but like Gina's orchids, live in a very wet and steamy environment.

I agree with Lucy, to the extent that I have this one oncidium. This one.

Its not alone in the wire basket. Years ago to save space, I stuck a couple different orchids in there. Ones I thought could 'get along'. One of those orchids in there is this Dendrobium. I stuck them together because neither particularly likes to have their roots disturbed, and I had no plan to repot. They are both yellow, so they look good together. The Dend kind of grows out the sides of the slats. There is no media of any sort in this basket except a few pieces of big charcoal and some big hunks of a terrarium hardwood. I can't remember what it's called. No bark, no perlite, no moss, no nothing. So it depends on me to water it on a regular basis, which I do with a hose sprayer, and it depends on high humidity.

I have never had any problem keeping my oncidiums evenly moist in pure sphagnum moss. Sherry baby especially seems to like it because she keeps blooming twice a year.

I was happy to find this thread, as my 'plain yellow' Oncidium needs potting. It had declined last year, a lot of sphagnum but conditions, including how I packed the pot, were different enough that it did poorly. I moved it to a vase but a lot of roots were/are brown. It bloomed, just about done now, but the bulb has shrunk. So, I'll probably try again in a pot of finer bark or looser sphagnum.

Oncidiums are an orchid I have not fully explored. The big yellow one I have above grows mainly as a lithophyte in nature, on rock outcroppings and crevices where it's largely dry unless it rains. But different ones in the group behave differently. I have a few Tolumnia, the ones people used to call 'mini-oncidiums'. They like to be in a tiny clay pot with nothing.
My fave oncidium type orchids are the Colmanara Wildcats. Bi=ut I don;t grow any....because it's just overall too hot here in the summer. I had a few years ago and they all died a slow death because they just don't like 90-95F

My large Onc Sharry Baby is just one large clump, I don't see the medium any longer. But, my small one really could use a repotting, I will just use smaller size mixed bark after I cover the hole in the pot with some loosened coconut fiber. Under my conditions, I water them daily.

Just look at an Oncidium's roots. Sharry Baby, the big yellow one might be Onc. Sphacelatum Gina, Colmanara, etc. So many have roots that closely resemble uncooked spaghetti. If you put a root system like that in a medium mix or in a pot too large, you will have watering issues.
Then look at Oncidium splendidum, the yellow flowered "mule ear" orchid or Oncidium carthagenense, they have thicker roots. They might do well in a mix with some medium bark.
But the reason that the pseudobulbs wrinkle or develop furrows is not enough water!

My yellow one is Sphacelatum.. I got in a trade with someone in Puerto Rico years ago