Advise for my Golden Tiger Crow Oncidium. Please help I've tried everything

[shelleynnn]

Hello, I've had this Golden Tiger Crow Oncidium for 2 years and she has progressively gotten worse with yellow leaves and black spots on leaves
I live in southern Florida this orchid is outside on a covered balcony year round. The balcony does not get any direct sun, it is north facing.

I had it in an all bark medium since I got it and recently switched to an all sphagnum moss medium. I tested the moss medium for about a month and the leaves still stayed yellow and pseudobulbs are still shriveled. I just added in more bark and less moss.

I thought maybe it was getting too much light and moved it back form the light further back on the balcony. I would assume yellow leaves mean too much light? PLEASE correct me if I am wrong.

I'm at a loss with what I should do? If anyone can please help I would really appreciate it.

Please see pictures.... The only picture where it looks green and healthy was when I first bought it.

The roots are dark (pictured) but firm
Thanks so much!

[rbarata]

I think using moss in your climate is worse than bark because they like to be slightly dry between waterings. In your humid climate moss is not needed for onc.
Put it under conditions that promote a fast water evaporation (but not full sun, bright indirect south light 70% max) and good air flow to avoid those spots.

[shelleynnn]

Thank you for the input. Any thoughts on why the leaves are more yellow than green?

[rbarata]

Originally Posted by shelleynnn

Thank you for the input. Any thoughts on why the leaves are more yellow than green?

Probably too much light. Put it in a shadier place.

[Swimmingorchids]

I haven't got any oncidium so some people would scould me for posting here but I will just add a disclaimer that I have never grown oncidium - still I will post.

The pseudobulbs are all dried and shrivelled up - the yellowing leaves are a result of this. This is your main issue.

Why they are dry is not clear. Like said never grown oncidium but I would have thought the roots should be a lighter colour.

Personally to me to see if they are "firm" or not indicates very little.

Maybe it's this fusarium I've been hearing about.

How often did you water it while it was in bark?

[Ray]

While I cannot be absolutely certain, I suspect your plant is Oncidium Tiger Crow. (There is no registered Golden Tiger Crow.)

First of all, I'd not grow that outdoors in south Florida - it's entirely too hot for the plant, and probably explains the slow decline. An air-conditioned space is far preferable. A north-facing window might not be bright enough, but you're right to keep it out of direct sunlight.

While those roots might be firm, they are by no means in good condition. The collapsed pseudobulbs are a dead giveaway that the roots are not keeping up with the plant's needs - or weren't in bark, as we don't know how long it's been in moss. Be careful with sphagnum - it's easy to water log it. A good root growth stimulant like KelpMax might not hurt.

Have you been feeding it at all? If so, what formula, what mixing ratio, and how often?

The spotting is likely acidovorax (AKA pseudomonas or bacterial brown spot). Treat the plant with a systemic copper compound like Phyton, a topical spray like Physan, or my preference, a probiotic like Inocucor Garden Solution. As long as water droplets don't sit on the leaves or splash to other plants, it's relatively easy to eradicate.

As Swimmingorchids suggested, it's possible the overall desiccation and dull appearance is caused by fusarium, but considering the cultural issues, it's hard to say for sure.

If that was my plant, I'd bring it indoors, treat it with the Inocucor product, and water it sparingly but keep it evenly moist.

[shelleynnn]

Thank you Ray for all the information. It was in straight bark for the last 2 years and has progressively gotten worse. Then I read that they like moisture and to use moss. Guess that was wrong!!!!
I used moss for about a month and no improvement.
it is now in a bark/moss mixture
I will try your suggestions

I use miracle grow orchid plus fertilizer, 20-14-13 very diluted, I know its not the best.....

I will go back to an all bark medium and not water it so often.
I think the black spots might be from rain water. I did have this near my screen on the balcony and water would get on it when it rained

[Ray]

Originally Posted by shelleynnn

Thank you Ray for all the information. It was in straight bark for the last 2 years and has progressively gotten worse. Then I read that they like moisture and to use moss. Guess that was wrong!!!!
I used moss for about a month and no improvement.
it is now in a bark/moss mixture

Moss and bark might be fine - I'd probably go with 75% bark - airy, tet still holding moisture.

Originally Posted by shelleynnn

I use miracle grow orchid plus fertilizer, 20-14-13 very diluted, I know its not the best.....

It's probably OK, but "very diluted" tells nothing about the actual amount used per gallon nor how often you use it.

Originally Posted by shelleynnn

I think the black spots might be from rain water. I did have this near my screen on the balcony and water would get on it when it rained

That's certainly possible, as standing water droplets become great incubators for bacteria and fungi.

[WaterWitchin]

I believe I have the same plant. For a very long time now. My tag says Ondontocidium Tiger Crow “Golden Girl." which is likely where the OP's Golden Tiger Crow came from.

Because of the Ondontoglossum (sp?) in its background, it tolerates less heat. And tolerates moisture... just needs good root circulation (air).

The blooms seem to last FOREVER. It's worth saving and cultivating, in my opinion!

PS Please feel free to correct those spellings... I'm winging it.

[Ray]

Interestingly, the odontoglossum in it's background has been reclassified, so it's all oncidium now. This cultivar has been awarded, so the label should currently read:

Oncidium Tiger Crow 'Golden Girl' HCC/AOS.