Phalaenopsis with white fungus on old stem and yellowing middle leaf

[erickar]

Hello everyone,

I have had my phalaenopsis orchid for about a 1.5 years but would consider myself still very much a novice. I have had no issues with this plant until recently.

This fall my orchid dropped two lower leaves. This was a little concerning as last year it only dropped one but it started growing a new upper leaf so I assumed everything was okay. I recently moved so I figured it may be under a little stress.

Since it seemed healthy I decided to repot it as I have not done so since getting it and it had really outgrown its old pot. It was originally planted in bark but I've heard that many people plant in sphagnum moss so I thought I would try that out. I repotted it last week in the moss but now there is white fuzz on one of the old stems and one of the middle leaves is starting to yellow. Attached are pictures for clarification.

When the orchid was in the bark I would water it by submerging the pot in water for 5-10 minutes and then letting it drain out. I would do this every week or so and it seemed to love this. It grew beautiful leaves and had flowers from april to august. I tried watering it this way with the moss and noticed that it was still damp days after watering, which may be the cause of the mold? The bark never stayed wet for long. I'm considering switching back to bark.

I also don't know why one of middle leaves is yellowing. When I transplanted I checked for root rot but all the roots looked healthy. Is there anyway to reverse this? I would hate for it lose a third leaf this year. The smaller one underneath is fine so far.

I have also been battling fungus gnats with some of my other house plants. They would crawl around on my orchid but they did not seem to be affecting it in any way. Fortunately I've been able to get rid of most of them now.

Any help would be greatly appreciated!