Why is this one yellowing?

[sachmoGT1]

I watered it on Saturday and it started yellowing! The pot has a little hole on the bottom. Is it still overwatered?

[aliceinwl]

Phalaenopsis tend to do better in pots with a lot of air circulation: holes in both the sides and bottom. Could yours have received some direct sun exposure leading to a burn? What is root health like? The visible roots look okay, but if it’s growing in moss in a ceramic pot with only a single drainage hole, the roots in the pot may not be in great shape.

[orchidwitch]

My immediate assumption without knowing the whole situation is dead roots. Phals don't do well in moss, so it really should be planted in bark chips or another chunky, airy medium asap, and preferably in a container with better ventilation. Even your top roots look a bit on the grey side. My guess is that it will be dropping those leaves soon. If you gently pulled on them, I wouldn't be surprised if they fell off in a matter of days. I get a lot of grocery store orchids from friends and coworkers that are shoved into cheap, non-ventilated pots as well-meaning gifts (they know I love orchids, but they don't necessarily know what to look for, bless them) and this happens quite frequently if neglect to move them to better mediums/pots soon enough. It might not be the nail in the coffin just yet, but you really need to pull the roots out and examine them to see what's truly going on.

[BrassavolaStars]

Hello All,

Something I would definitely be watchful of is stem rot. Vulnerable phals in my experience seem to be easily infected by this condition if moisture, air circulation, and watering conditions are not ideal.

Additionally, it also seems like the yellowing started at towards the base of the leaves and then moved towards the tip of the leaf. When I have had this happen to me, it has sometimes been root rot that became stem rot. I do not think that has happened here necessarily, but just be careful and make sure water stays away from the crevasses between the leaves.

[Ray]

First of all, please understand that different folks have different opinions and experience, so take all advice with a grain of salt. (My phals do great in plastic pots of sphagnum...)

That looks like terrible moss, but I suspect, as others have said, you have a terrible root system on that plant.