Oncidiums, specifically, still hate me. Continued die-off, some add'l. q's re: Phals.

[captainbug]

I'm looking for a good way to control gnats as well as what seems to be a rotting issue on my phals, oncidiums, and dendros.

I discovered recently that many of my oncidiums were dying because I mistakenly planted them in aerated pots...but with a mix of peat moss, bark, and potting soil. They decided they were extremely unhappy and I think I'm now on the tail end of a huge dieback issue after repotting them in coarse bark with some sphag moss mixed in.

[Here is a recent-ish pic album before repotting](Imgur: The magic of the Internet).

[Here is a current album, including pics of my phals](Orchid issues - Album on Imgur). Yes, they are due for watering today which is why I'd like to determine my next steps with them.

I did lose the most unhealthy looking oncidium that had tons of brown going on, unfortunately. Zero root growth, dead roots, and a maggot in the remaining pseudobulb.

Here are my issues summed up:

* The gnat issue. I don't notice any other pests at this time, thankfully. I did previously have a rolly polly and some little white critters and drying them out took care of that.
* The Mendenhall Hilldos looks okay. I noticed today that it's even putting out new roots from and old pseudobulb.
* The tiny baby dendro seems to be okay. Its new little growth is coming in little by little.
* Some new leaves on phals are coming in purple on either the bottom or edges. They seem strong and healthy, so I'm assuming nothing to worry about?
* Some phal leaves are rotting with a weird black/brownish rot that looks wet but doesn't feel wet.
* The bushy oncidium seems to be doing okay. It's growing out a watering issue that it had when I first got it and new growth seems to be coming in straight, but it does have the occasional leaf die from the tip down--is this an issue?
* New growth on purple potted oncidium is going black on the outside leaves at the base, there appears to be mold. Is this mold, and are those young pseudobulbs salvageable?
* Generally beaten up looking larger leaves, some old black spot, and new tiny black spots. Are these spider mite issues? No other evidence of spider mites (no webs, no red streaking on moist paper rubbed along bottom of leaf).
* Fixing to lose two more leaves on the bottom oncidium, and one on the 2nd from the bottom... Neither has any more leaves to spare. How do I stop this?

Is my potting mix still too moist? Do I need to pull out the sphag entirely and let them be in just plain coarse bark w/ the charcoal and perlite bits?

These oncidiums were a dream to start with, but now it's like they just flipping hate me. The vast majority of growth happened when they were bare-root for the period of a few days that I was waiting for bark to arrive and had to get them out of the soil mix. I could theoretically keep them bare root, but I have no idea how to do that and there's little/no room for error when they need to be misted thoroughly 2x a day while bare.

All are kept inside under LED grow lights that are appropriately distanced from the plant. Inside temps are about 76F, and I do have a fan running. It's not possible to put them outside due to deer and extraordinarily high temps.

---------- Post added at 06:56 PM ---------- Previous post was at 05:49 PM ----------

Onc roots - Album on Imgur

Here are roots after baring and soaking for about 10 mins...

The littlest one (3rd pic) looks like it lost new root growth, most are pretty papery but it seems like some soaked up water.

The largest one (last 2 pics) seems to only have mold where the media was rubbing up on the new pseudobulbs. Were they maybe planted a bit too deep? Green roots tangled in the mass, but most of the roots soaked up some water.

The middle one (first 2 pics) seems to be doing ok root wise. Not much new at all, but definitely wouldn't call the rest dead by any means (even if the mass of them is ugly).

[aliceinwl]

The Phals look okay from what I can see. The purple color is often a response to high light levels, as long as they’re not burning they’re fine. If you have any in clear pots, water everyone when the roots go silver. If not, water as soon as it looks like the substrate is dry.

I think you media can work, but it’s going to take awhile for your plants to recover. Oncidium types don’t like to dry out completely, but they don’t want to be soggy either. You need to figure out a watering frequency that leaves the media moist but not wet and water as soon as it approaches dryness. I have a lot of mine in clear slotted pots so I can visually judge moisture. You may find the skewer method in the sticky helpful since yours are in opaque pots. With the grade bark you have you may be looking at watering around twice a week or more.

Right now, I think a lot of them don’t have the root mass to support the foliage so they’ll draw from the pseudobulbs until the new roots grow in. I wasn’t sure which one you were seeing the mold on, but it’s normal to get mold on dead roots. It’s not pathenogenic and is just part of the natural decay process.

If you don’t see any improvement within a month or so, maybe try a move to a fine grade bark mix, some Oncidium types also really like to hang. I killed all the roots on my first Oncidium types too. For one a move to a fine bark from coarse did the trick. The other one didn’t start putting out roots until I put it in a hanging basket. It took me two years to get the first one recovered and reblooming and three years for the second one, but I think less hardy plants would have just died. Be patient, these guys can take quite a bit of abuse.

[King_of_orchid_growing:)]

Don't soak them anymore. Just water. Water 2 - 3 times a week and see how things are going. They have very minimal root structures to draw water from because the old roots are either badly damaged or dead, as was mentioned prior, they will draw moisture from their pseudobulbs. Once the new root system grows larger, some of the newer pseudobulbs will look plump (without wrinkles).

If they are soaked, you run the risk of rotting out the new roots.

Patience is the key. You've got new roots coming along, don't damage those. Don't worry about the old roots anymore - they're done.