Something I have begun to notice, and in retrospect it makes some
sense given the problems I had in the fall with phals, is that when I
get phals that had been potted like most of the dendrobiums I have
bought (packed tightly in sphagnum in 10 cm clay orchid pots (i.e. the
ones with the slots in the side), the phals suffer significant stress;
and until I clued in on this, they died. I suspect that the folk who
packed them in the sphagnum packed them so tightly that even though it
takes three to four days to dry out when the humidity is so low, there
is effectively no air available to the roots while the moss is moist.

Ditto here. What I have found when bringing these in from Hawaii where they
come in NZ sphag is that the plants continue to flourish for several months,
but then begin a decline.

And it is always the roots. Not only can there be no air getting down there,
but the core of the medium remains terribly wet. When in NZ, I usually water
Phals every 7-10 days and still the centers stay sopping wet. BTW- these are 4
inch plastic pots! Not exactly large.

The trick I have learned is to watch for significant root growth outside the
medium- specifically significant root development between the leaves and
otherwise above the crown of the plant. I try to repot into my usual mix before
this takes place, but once I see it then I know it is time to make repotting a
priority.

But it also bears remembering that when I leave the Phals in the NZ mix for a
few months, I do not have the "Hawaii effect" whereby the plants slow down
after being raised in such idyllic conditions before coming to me. I do not
know why this is, but if I pull them out of the NZ too soon, then they do get
more sluggish for a while.

Take care,

Tom.