Cymbidium orchid leaves discolored. Fungus? Underwatered? Over watered? Please help

[SouthPark]

Nmari - as a precaution - if you ever see any softening or rot near the BULB region ----- apply some fungicide such as Yates Anti-Rot Phosacid. Can easily get this from Bunning. But make sure it is mixed to the correct (right) proportions (ie. don't overdo it).

For your deep orchid pot - my recommendation is to put lots of big holes at the bottom of the pot. Use a cheap soldering iron from say JayCar if you have to ---- to burn holes through the bottom of the pot. Good air-flow from top to bottom of the pot (or vice versa) - through the media - and all around the roots ----- will help a lot to prevent fungal and rot issues.


Also, a potting media that restricts air-flow through the pot too much ----- can create issues like fungal activity, oxygen starvation of roots, rotting etc. inside the pot. So choice of media and size of media pieces should be considered.

Also - is your orchid pot sitting on a stand for preventing the bottom of the orchid pot from ever sitting in drained water? If there's no stand - then put some sort of grate or stand down the bottom, so that the bottom of the orchid pot (where the drainage holes are) never comes into contact with drained water. Allowing water to fully drain out of the orchid pot is very beneficial to the orchid.

For the orchid bark - use suitable orchid bark --- like orchiata bark.

Some kinds of bark may well contain something that could possibly negatively impact the health of the orchid.

Bright - indirect sunlight - should be no problem. Did you apply any fertiliser that could have possibly accumulated too much salt in the pot? Roberta suggested something like that already - and salt buildup will indeed lead to that sort of effect on leaves.

Warm and humid - no problem. Just make sure the veranda has some natural air-movement --- at least most of the time. Still-air for relatively long periods of time (- hard to say absolute lengths of time - but let's say half an hour, or even one hour, or more than an hour of next to no air movement) could possibly create issues for the orchid.


Above: Along the bottom of the photo - Oncidium Twinkle and a couple of Oncidium Sharry Baby - growing very well in scoria.

[Cym Ladye]

My biggest concerns here are as follows:
1) Over potted in too large a pot.
2) Crown is not covered with mix. There are two new growths showing but if the plant is moving at all, the new roots will be deterred from settling down in the mix.
3) Although you have used a larger bark than I would deem required, I suspect you may be over watering. Newly repotted and divided plants benefit from a drier start than may be the regular routine as the roots have not established new growing tips.