Leaves on my paph seedlings are turning brown.

[Elli]

I have two different types of paph seedlings, that I deflasked several months ago. They were doing quite well until about three weeks ago. Leaves are changing colour and the plants are dying... I have used Mancozeb on them, but so far no change. They are growing on a northwestern window sill (southern hemisphere) with shadecloth in front of part of the window. So they do not get full sunlight, rather filtered through the shadecloth. Also the window is open most of the time, so no glass in front of the seedlings.

I don't want to loose them all, as they were also meant as a little investment.
I hope someone can help me!

Thanks!

[aliceinwl]

I'm not too experienced, but it might help others troubleshoot if you can tell us what kind of Paphs you have and how you're growing them in terms of lighting, temperature, substrate etc.

[katrina]

Pictures of the plants might also be very useful in diagnosing the problem.

[Elli]

Thanks. Have edited the post

[katrina]

The first thing that jumps off the screen at me is the very large bark for such tiny plantlets.

How are you growing them? Light? Frequency of water? Temps? Any and all details as to what you've been doing up to this point. We have some really great paph growers here (not me) and the more info you can provide, the better they can help.

[aliceinwl]

Caveat: I've never deflasked any orchids and all my Paphs are hybrids that were listed as "easy", so take my advice with a grain of salt.

To me, the substrate looks too large as do the pots. Paphs like to be evenly moist never completely drying out but not soggy either. I have mine in much smaller pots in fine bark (my single seedling sized Paphs are in 2 inch pots or smaller). I also have one in loosely packed spagnum moss that is doing well. It seems to me that it would be difficult to have relatively even drying in your pot and that the upper layer may be prone to drying completely while the lower part is still wet. Maybe switch to smaller pots and a finer mix?

I've also had Paphs drop leaves when regularly exposed to temperatures below their tolerance range. I'm not sure if this is a possibility? I thought mine were fine until the lower leaves suddenly became discolored and started dropping after several weeks. I moved mine to a warmer location and I think they'll pull through.

[Paphluvr]

Being in the Southern hemisphere you're just going into Summer, correct? Days are getting brighter and longer. I think that even though you have shadecloth over the windows the exposure is too bright for seedlings. As other posters have observed, the potting mix is very coarse for seedlings. You also mention that the windows are open most of the time. What kind of temperature swings have they experienced?

[Elli]

Unfortunately it is nigh impossible for me to get finer bark here. I might try hitting some with a hammer to make it finer. ☺

Temperatures vary from 30 to 35 degrees celsius at the moment. Dry season temps are 15 to 30. There are high trees about 5m away fron the window, so the time of sunshine on the window is around lunchtime.

They were all doing well until recently and had new growth. So I wonder if it might be the heat getting to them as I do not run aircon in my house...

[Paphluvr]

If my calculations were correct that translates to 86-91° F. These are higher temperatures than I would normally keep seedlings coupled with the most intense sunlight at the worst part of the day (I normally consider 12-5:00PM the most intense). Did you have any air-flow on these seedlings?