Gradual Leaf Drop in Pleurothallis Allenii

[Ermie]

Recently, I believe about a month ago, I received a Pleurothallis Allenii. Upon arrival, two leaves dropped. At the time, I dismissed this as shipping stress. Now, about a month later, four more leaves have proceeded to suddenly turn yellow and drop, about one a week. The plant still looks very healthy and whenever I think no more leaves will drop, a leaf will yellow over the course of a night or two and drop.

The only conclusions I could come to are humidity, which hovers 50%-60%. Soon it would be moved into an environment with higher humidity (75%-85%), I'm hoping that helps.

Growing conditions:
Temp: 65 at night to 75ish in the day, occasionally lower.
Water: Always moist but not sopping wet- I water when it is very close to drying out.
Light: East facing window- although partially shaded by a small dendrobium.

[estación seca]

Nobody is replying, so I'll jump in and show you why I don't grow them.

In the top maroon menu is a Search function. Click on that, then Advanced Search. In the Keywords box at the top left, type in allenii. In the Forums list at the bottom right, scroll down to Pleurothallis Alliance and select that. Now hit the white Search Now button at the bottom left.

The bottom thread contains some really good growing information. Some of the other threads contain mouth-watering photos.

I'm going to guess your humidity is way too low and raising the humidity is a right-now emergency. Put the plant in a large glass jar right now so it is more humid.

[estación seca]

Bump. Would somebody who grows Pleurothallis care to comment?

[catherinecarney]

I bought an allenii a couple of months ago and grow it in 40-60% humidity, dappled shade about 3 feet back from a south window, temps in the low 60s (day) to high 50s (night) and have not had any leaf drop issues. It's potted in a mix of small bark and bonsai mix (fine gravel/coarse sand) and seems to be happy.

The only difference between my conditions and Ermie's is the temperature range. Could that be a factor?

Also, have you checked the roots? Any dark/soft spots on the roots/leaves/stems?

Just tossing out ideas. Hopefully someone with more experience will chime in.

Catherine

[Ermie]

Thanks Catherine for the pointers, the roots are fine and so are the leaves, that was one of the first things I checked for was rot or other. The only thing I can come to are the temperatures, although I've found several sources stating they can tolerate temps in the 70's. In a week or two my humidity chamber will be back up- I'll see if that helps if the issue isn't resolved by then.

[catherinecarney]

Sorry I don't have more ideas for you--hope it perks up!

Catherine

[Ermie]

I can't get a picture of it now but the new leaf that is yellowing is almost completely yellow but still fleshy and hydrated...

This behavior is completely new to me. It is also reddish as if sunburn although no other parts of the plant shows sunburn...