phalaenopsis leaves stop growing

[julianeve]

Hi guys ...

So during winter I moved my phalaenopsis to another window where there was no central heating right under it. The window is on the same side of the house, literally just like 10 metres or 30 feet to the right.

(I have had them there previously and they were super happy in both places.)

Suddenly quite a few of them seem to have issues that I cannot identify and don't know what to do. The room is no different than before, the weather also, I have always had impeccable orchids, nothing was wrong. Suddenly a few started this thing where they grow a leaf and it is either really strange (and maybe diseased?). As per advice of fellow orchid lovers, including you here, I would cut the leaf that was unwell and wait for a new one. Which happened but they either grow smaller and shorter and start growing another one immediately or they start drying up and growing a new one. Two instances in the photos.

Anyone have any idea what this is, what to do, how to treat it, is it possible?