Oncidium health question

[Pimparella]

Hi everyone,

I am new here and I am really looking forward to learning a lot from all of you!

I am in a situation which looks really similar to what farley101 has had.
I have this Oncidessa sweet sugar (which looks like the one in the pics) that it has not been too good for the past few weeks. Although I watered it as I know oncidums enjoy a fairly humid soil, the pseudobulbs started shrinking. By now I have understood that what most probably has happened is that the medium was not very good (too compact, mostly perlite) and not ideal for my environment and so the roots started rotting.
However, although most of the pseudobulbs were full of wrinkles, there were 2 new pseudobulbs (visible in the pics below) which were also developing new roots.
I decided to go for repotting and I did it 10 days ago. I put mostly bark and some sphagnum. Most of the roots were gone but there were still some left.

Anyway, 10 days after repotting, I am now here with these pics, there does not seem to be much of a difference with 10 days ago and I am not too sure what to do. Should I just wait or do something like sfagnum therpay.

What do you think?

I am really looking forward to your advices!

[Roberta]

First, welcome to the Orchid Board!
10 days is nothing in the life of an orchid - they don't do anything fast. They teach patience. The new growth will produce new roots, and your timing was excellent! Don't worry about the old pseudobulbs wrinkling... they will, especially since they are rather rootless. However, they hold the reserves that will keep the plant going until the new roots and new pseudobulbs have a chance to mature. Eventually those old psudobulbs will die, but by then you'll have the new growth established. I think that what you have done is fine...just let the plant do its thing. Let it dry a little between waterings, but not go bone-dry. How often? You'll learn that by observation.

[SouthPark]

Originally Posted by Pimparella

the medium was not very good (too compact, mostly perlite) and not ideal for my environment and so the roots started rotting.

For the oncidium of this size, my preferred choice of media is volcanic rock ---- I use scoria --- 5 mm average diameter, up to 1 cm diameter pieces. A mix is just fine, with a good drainage pot.

Good drainage and good air-flow through the room and through the pot is beneficial. Having an environment that has good natural air-flow (gentle breeze) is beneficial for the plant. Still air environments can create issues.

With bark - which is what you're using, and which is quite ok - make sure you pre-wetted the bark (eg. soaking in a bucket for quite a while) before using it for potting. Also remember that dry bark repels water, which means the orchid can die of dehydration if most of the water runs right out of the pot, while the dry bark remains dry - as it repels water. That's why some people have to dunk their orchid pot in a tub of clean water for 10 minutes or more when they water - in order to get the bark wet. On the other hand, if the bark remains damp, then general watering methods will work just fine.

[Pimparella]

Thank you so very much Roberta,for the warm welcome and for your advices!

---------- Post added at 10:49 PM ---------- Previous post was at 10:44 PM ----------

I used bark mostly and some sphagnum. While Phal and Paphiopedilum gorw up really well in my home (which is dry and sunny), I have had a very bad luck with oncidiums so far. They all ended up dieing.
Although I soaked them for not more than 8 minutes once a week, the soil kept being wet and wet for way too long and this eventually killed the roots.
Just to say, yesterday I noticed that some of the roots of an oncidium which actually looks really good were having some mold on them! I assume the medium the oncidiums are sold here in Italy is not good for my house-climate.

[SouthPark]

Originally Posted by Pimparella

Ventilation, well, I grow my orchids in my apartment and in the winter time the time is not ventilated, I mean, i dont keep windows open, unless for little time a day

They can survive and are known to survive without too much ventilation. But it's also known that beneficial conditions include good ventilation to the entire plant (roots and all) and the media, and good comfortable temperature.

I think your orchid should be ok now, after you have re-potted it. As long as the leaves remain nice and green and don't deteriorate, then that will be a great sign.

[Roberta]

Originally Posted by Pimparella

I assume the medium the oncidiums are sold here in Italy is not good for my house-climate.

What works for a commercial grower may not work for you. I have found that almost all orchids that I buy need to be repotted... nobody pays the grower to repot, they keep the plants going until they bloom, then sell them. (This is true pretty much everywhere) The stress may even help to push those plants to bloom... they want to reproduce before they die. So ... in general, consider repotting soon after you get a plant, especially if it is putting out new roots and new growth. Even if it is in bloom... with careful handling the flowers won't ever notice that the plant has moved to a "new home".

[Pimparella]

Thanks

I'll surely keep a close eye on it, on the leaves as well. Some of which did have some light sort of spots on them (especially if you look at them backlight).

Yes, I have by now heard that it's always good to repot them once you buy them and while with Phal there has been no need so far, with oncidium this seems to be absolutely necessary.
Thanks again!

[Pimparella]

Hello there!

So, the end bits of the leaves are a bit yellow. I was not feeling too positive about its recovery and so I removed the full orchid from the pot to have a closer look at it (not that it took me an effort as, being almost rootless, it came off easily).

This is how it looks right now:

https://imagizer.imageshack.com/v2/6...921/WounIN.jpg
https://imagizer.imageshack.com/v2/6...924/ZzKW0B.jpg
https://imagizer.imageshack.com/v2/6...924/YMyDa6.jpg

So, it seems to have some green roots that are developing (correct?), apart from the air roots which are clearly visible and that were there also 10 days ago.
I looked at how to do sphagnum therapy online but this seems to be doable only for completely rootless orchids, while mine is not. So what I did was to remove a good bit of bark and replacing it with sphagnum so that now the base of the orchid is on the sphagnum which I am planning to spray with water every day or so.

What do you think? Is te better to go for sphagnum therapy all together?

Thanks a lot for your valuable support!

pimparella

[Roberta]

If new roots are starting, it should be fine if you pot it into its new permanent home. Put the oldest part against one side of the pot, so that there is maximum room to grow. It will produce new roots from new growth, draw on the old psudobulbs for energy in the meantime. (they'll shrivel, no worries there) Since it lacks much in the way of roots to stabilize it, a stake is a good idea - it is really important that it not wobble while those new roots are developing. Keep the medium damp but not wet - until it has roots it will have no way to absorb water. If your air is very dry, you can create a "mini greenhouse" by placing a plastic bag over the plant to minimize loss of water from the leaves.

[Pimparella]

Thanks for your reply

"If new roots are starting,"
So they do look to you like new roots?

What would you use to tie the stake to the orchid? which kind of material? Also, I suppose the plastic bag should not touch the leaves, right?

Also, how often should I remove the plastic bag to spray water into the sphagnum?

Many thanks!