Al ) wrote:
: Usually this is an indication that the leaf tissue did not have enough
: available water to fully expand the cells in it while the leaf was young and
: trying to expand to its full size. If this is the case with your plants
: this condition does not reverse itself on a leaf already pleated but keep an
: eye on the plant and when new leaves start to grow make sure you increase
: the amount of water available to them.
OK, that makes a lot of sense.
: I have seen Oncidiums and Cochleanthes type orchids do this. Cochleanthes
: (The Bollea tribe?) do it if you just walk past them with a hose and do not
: offer water. I suspect any orchid with thin strap-like leaves can be
: susceptible to it. Phals, being a bit more succulent do not do pleat in
: quite the same way from lack of water; instead they get kind of wavy and
: their edges turn under. I think newly emerging Cattleya leaves also express
: their dissatisfaction with the amount of available moisture in the same way
: as Phals.
The plant that I'm having this problem with right now is a Brassia verrucosa
so that matches suspicion about thin strap-like leaves. It got under-watered
after I first acquired it and before it got moved into a basket. It gets
regular attention these days so we'll see if this problem goes away. Slightly
OT but I had read that Brassia don't like being disturbed but this particular
individual is going gangbusters developing a lot of new roots after moving
from the pot it came in to the basket.
The other plants I've seen this pleating on are my Cattleyas. The watering
explanation surprise me a bit here as I would have guessed that my Catts
are a bit overwatered if anything. I mix some potting soil and vermiculite
with the bark that I use for potting so that it retains moisture better than
just bark alone.