I suggest not feeding until it's been thoroughly watered first if underwatering is the culprit.
Sphagnum is usually safest, but if you're not comfortable with that, may I suggest mixing sphagnum with bark or LECA in the proportion that suits you? Maintaining water and humidity for orchids in a household situation can be tricky. I also suggest a modest increase in light. Phalaenopsis can take diffused southern exposure in northern environments like yours.
Hope this helps.
|