Please help -Oncidium root rot!

[Sahlabiya]

Hi Again,

I keep writing about this Oncidium - it keeps taking new turns for the worse . I had taken it in to the nursery where I bought it when I first caught that it had root rot. They helped me repot it, put it in ban-rot and repotted it in a media with fine bark, shredded New Zealand Sphagnum, small pumice. Since then no new green growth has occurred, and I keep finding more rotten things. I pulled off a brown pseudo-bulb this morning, took it out of the pot and of course found more root-rot. I have only watered it once a week since I had it re-potted. I tried to email the nursery again but they did not answer this time.

I did my best to take out the rotten roots but it is so hard to find them in the whole tangle of roots! At the moment I have it in water with fungicide (Agri-Fos) and I plan to let the roots dry for the rest of the day. I am wondering what I should use for media that will give it the best chance for life? The media was quite damp when I pulled it out and I last watered four days ago.
Any help would be much appreciated - I really hope to save this orchid!!

[Carpe Diem]

I am still a newbie, but if I had root rot on any orchid, I would do away with the Sphagnum.

[Sahlabiya]

Should I use fine bark and Hydroton?

[Carpe Diem]

I only have one Oncidium, a Twinkle, it is in fine bark mix. You can mix in Hydroton if you like. Go to some sites that sell Orchid supplies and take a look at what they suggest for fine root orchids. repotme.com, Kellys Korner, Tindara are some good sites to check out.

[Sahlabiya]

Thanks I am excited about this website repotme.com - just learned about it today!

[WhiteRabbit]

Make sure you aren't over-watering. Using a skewer in the media to determine when to water is very helpful.

[james mickelso]

Take it out of the fine media that it is planted in and put it in a medium bark mix "WITHOUT" spagnum moss. After you repotted it at the nursery you should have left it alone and not watered it for at least a week. Then watered it lightly. Root rot needs to be left alone. It is not rot at first but just dead root mass. It needs to dry out completely. The rot sets in when the dead root mass is watered again and rot sets in. Wet media is what caused the problem in the first place and then it is compounded by plunging it back into more wet conditions with fungicide/bactericide/ect. Let it dry off and let the plant tend to healing. The pbulbs have enough stored moisture to last them a couple weeks. Let them heal. Take it out of what it is planted in right now. Put it in a medium sized bark and do not water this for at least another 10 days. Then water it and let it dry completely before watering again. You may be able to save it but it will be touch and go. The only thing to be hoped for is new growth from the back bulbs.

[Sahlabiya]

Thank you so much for this. I had been advised to water it two days after returning home from the nursery so I did it. I'm still learning about when it's necessary to let plants dry out. Anyway I bought an orchid pot (I had had it in a regular clay pot) and repotted it in medium bark + charcoal + clay hydroton beads. I went out of town for a month and instructed a friend to water it once a week. It looked nice and green when I picked it up (though no real new growth) but a closer inspection of its roots showed that some were still mushy with string cores. After taking those off and dusting with sulphur powder I've just put it into dry medium bark and will follow your guidelines - we'll see if this time it really mends....