Rot on Paphiopedilum?

[SouthPark]

Originally Posted by monivik

I've got a bit of a breeze (that is when I'm home). I also have a small fan in the living room.

Sounds workable over there! Are there any significant amounts of time during the day or night where the air is completely still? As in the doors and windows are closed and the air becomes fairly still?

The way I sometimes think of it is ---- but not necessarily for your case ---- is something like a bathroom or shower room. If there's not enough airing - like air coming through to allow for enough airing, then mildew etc starts growing on the walls - in crevices, gaps between tiles etc. But adequate airing significantly cuts down on that kind of thing - or even stops it.

For the orchids --- not necessarily mildew ---- but other fungal activity could possibly start up on leaves and in media or roots. There's going to be unharmful fungal activity maybe, but may be also potentially harmful activity too - for orchids that is.

The above isn't necessarily the cause of the browning of the regions of leaf for your orchid.

Just thinking about temp, temp range, light level, light duration, humidity, air movement. If the media and watering schedule is good, and root health is good (and the roots your orchid actually does look pretty good from what we can see -- in terms of colour/health) ------ then take a close look at those other conditions (air movement, temperature range etc). It sounds like temperature has been quite ok there. So consider air-movement.

If there happen to be significant durations of time where the air is pretty much very still ....... and if not much air passes over leaves and through the media and over roots etc, and through the pot etc ..... then maybe something could possibly start up from there.

It seems that some orchid growers don't have issues with the orchids even with significant amounts of time in still air (indoors) ------ but maybe humidity considerations need to be factored in for those cases. As in if humidity is low, then a different story. But sometimes those growers (not all growers, but at least some of them) might not even understand why their orchid has no issue, and so (maybe mistakenly) assume that they can just have orchids growing very nicely indoors with little to no air-movement for any place. I don't mean you ----- I mean some growers - not for criticism. Considering possibilities only.

Beautiful leaf pattern on your paph!