I've got several orchids that I keep on a windowsill and they seem to have been doing fine but at the end of the summer 1 of my phalaenopsis developed a bumpy rough patch on one leaf its silver ish but it seemed fine continued to flower and I could see no pests. My second phal then also developed a similar patch which ends where it is shaded by another leaf so I was wondering if it could be sun burn but the leaves have not tured yellow or black and the plants are sending up spikes and leaves seeming otherwise healthy. Please could anyone give my any idea of what is wrong with them and what I can do,
Thanks Alice