Miltassia Dark Star 'Darth Vader' help please

[silken]

In Oct. my friend gave me a fairly large plant of Miltassia Dark Star 'Darth Vader'. It was nice and healthy looking and she had just split up a huge plant and potted the pieces in SH. Not knowing what really to do with SH (It was in all leica balls) I set it in a shallow pan and put it under the lights with some other potted orchids. The shallow pan had a bit of water in it at all times. But within a few weeks and until now, I kept seeing the odd leaf turn yellow and I was concerned about rotting the roots. It is kept in the greenhouse. That area gets to about 67 or 70 in the day and down about 10 degrees at night. Lights are on for 12 hours. I just un-potted the whole plant today and I I think most of the roots are dead. They are not mushy, but brown and rather firm. I don't have a lot of experience with oncidium types but I thought the roots would be a lighter colour. I pulled some away and some of the old bract leaves beside the bulbs are mushy and I tried to clean all that up. I cut it in two pieces and a 3rd small piece just fell off. There are new growths on all 3 pieces but not many new roots with the new growths. Orchid Wiz says common potting media is bark. It doesn't say small or medium. The roots are very fine. I have very fine bark for some of my Paphs and medium bark that is about 1/2 to 1 inch in size. I also have sphagnum moss.

I would appreciate any ideas as to how to proceed with potting these. I am tempted to soak them for a few hours in water treated with KLN rooting hormone, but do I dare give them any more water in large amounts? And then what do people use to pot these plants for good success? Any tips would be appreciated. I will hold off and hope for some responses.

[quiltergal]

I have one that is growing well in a fine CHC mix. The transition to SH is often traumatic for plants especially if they were repotted at the wrong time. Part of the process in SH is the old roots do rot because they can't adjust to the LECA. Once the new growths get going they will grow new roots that will do fine in SH. You really can't over water with SH. Check out the SH forum and/or visit First Rays where he explains everything.

[silken]

Thanks for the info quiltergal. I think this was re-potted in Oct. so that likely isn't the best time. I maybe should have left it in SH based on what you have said, but was getting concerned about the yellow leaves. I ended up soaking the pieces in water with KLN in it. I don't have anymore CHC as I never did too well with it. Several times when I checked a plant that wasn't doing well in it, I would find mold growing between the CHC pieces. I think I water more than is good and really try not to, but...

I am thinking maybe if I soak bark and some sphagnum moss in water and rooting hormone, and pot the pieces in that it will be a bit of a transition from the SH. The moss should hold the moisture a bit more than bark alone, and the bark will allow for some air spaces.

Any opinions on that?

[CTB]

when I repot a oncidium, I wait a week before watering sparsely. I water very little trying to give new roots a chance. That's why it's best to repot in the growing season if possible. Mold doesn't grow where it is dry, good sign of too much water. Sounds like you did the right thing.

[silken]

Thanks Carol and quiltergal for your help. I have re-potted one of the pieces and will finish up today with the others. I guess all I can do now is wait and hope I didn't kill them. I soaked the bark and moss pretty good, so now will hold off on water until it is dry for sure and then water very sparsely in the hopes the new little growths will put out some roots. Some of the mid size pseudobulbs are still very nice and plump and the plant looks quite healthy, until looking at the roots. Maybe these roots are supposed to be kind of wiry and brown. I don't have a lot of experience with this type of orchid.

[BobInBonita]

Don't have Miltassia myself, but assuming it is similar to other Ocidium alliance I'll offer the following:

Oncidium roots tend to be much smaller diameter than many others. Small and wiry doesn't sound bad.

Roots tend to pick up brown color from bark as it decomposes. If the roots are still firm, brown isn't necessarily bad, especially light to mid brown.

You've mentioned a "heavy hand" with watering. Since you used some sphag in your mix be especially careful to let it dry. If you get this before you repot the others, you might consider a mix without the sphag as a "2 plant experiment" to see which works better for your growing style.

Orchids like consistency and generally not to be disturbed too much. Yours have been divided, repotted, and now divided again and repotted again - all since November. I'd try my best not to stress them more.

Unless yours is a cool growing Miltassia, I think you might be at the cool end of the growing range. If you can warm it up just 5 or 10 degrees you may stimulate root growth and have better chance of recovery.

[silken]

Thanks Bob. I already had the 2 larger pieces planted, but the amount of sphag is not too great. I did plant the smaller piece in bark only, so I will have the '2 plant experiment'. I am also giving one of the larger pieces to a friend who grows in her house, which is warmer than my greenhouse, so that could be another experiment, but I may end up needing a piece back from her in that case . I do have heat mats, and am pondering that option as well. That would maybe stimulate root growth and warm up their little environment a bit. Any thoughts on that are welcome.

[WhiteRabbit]

My Mtssa has done well being kept lightly moist. Mine is also growing outdoors, so takes temps down to upper 30s for short periods at night - maybe not ideal, but doesn't seem to bother it - it has a spike right now - of course I need to wait and see what the blooms will look like lol. Warmer temps may help for new root growth - idk. Only new growth will get new root growth.