Why won't my Oncidium ornithorhynchum grow?

[GeorgeAdams]

I was given an O. ornithorhynchum last Autumn, but I slightly under watered it and the pseudobulbs have shrivelled and some of the leaves went brown. I have watered it more thoroughly in the growing season, but it just won't grow. Why?

[No-Pro-mwa]

Do you know how the roots look? If you under watered it it could have killed the roots. I have done this.

[GeorgeAdams]

The plant is basically root-bound. The roots are quite rigid and pale, as I am sure they were when I had bought it.

[Cntry]

Like No-Pro-Mwa said check the roots, make sure they turn green when they are watered. Cut off any the roots that are dead and repot up one size pot if you don't have to cut off a lot of roots. Use new medium the same kind that was in the pot. Let it rest for a week and water again. Use KelpMax or like product to help give roots a boost. Fertilize weekly using 1/4 to 1/2 of required amount per gal of water. Use a balance fertilizer also making sure all numbers are the same. 20-20-20 Happy growing!

[AnonYMouse]

What are your conditions (light, temp, media). Is it still declining? Or just stalled?

I believe this species has fine whitish roots (1mm ± wide) which maybe fussy about handling. Nevertheless, if it is unhappy, you do need to look below (the visible roots can fool you).

Do you know if the blooms are pink or yellow? According to IOSPE, the pink has been misidentified for nearly 200 years and is now called sotoanum. There is a slight temp tolerance difference between the two, the yellow is a cool to cold grower.

[GeorgeAdams]

It is an Onc. sotoatum (thank you).

[Sorry about the poor quality of the photos. They were taken on my phone.]

[AnonYMouse]

Your plant is severely dehydrated. It is underwatered or lack enough healthy roots take up water. As stated earlier, you need to check the roots.

If it were mine, I'd toss it. Get another.

If you are determined to care for it, remove all dead roots, soak in seaweed solution and repot into new media in a clean pot. Prop upright with stakes as needed.

[campchi]

The roots looks like all rotted. You need to remove all the dead roots and just put it ontop of some moss until it put out new growth. Soaking the plant daily will help. Make sure provide high humidity as the roots are not taking up water for the bulb.

[GeorgeAdams]

Most of the roots are a light cream colour, rather than grey or black on top.

[campchi]

Originally Posted by GeorgeAdams

Most of the roots are a light cream colour, rather than grey or black on top.

Feel the roots, is it still firm? if it feels papery, u need to remove them. From your pic, I think most of the roots have rotted. Just cut away all the dead roots with sterilize scissors and leave it sitting ontop of some moss, mist it daily(2-3x depend on your weather) to keep the humidity high and hope for the best.