Hi Pam

"profpam" wrote in message ...
"It had been potted in moss, and I repotted in coir on the
assumption that the two would have similar
properties WRT moisture."

Dendrobrium keikis and plants appear to do best when underpotted and
placed in either orchid rock or volcanic rock. A keiki requires at
least 2" of growth to be repotted.

Does this advice not depend in part on your growing environment? I would
think they'd do well in rock if their air is quite humid, but a medium such
as coir would be helpful in a climate like mine where it is a major
challenge to get the relative humidity up to 60%, even with a humidifier and
humidity trays. This winter, relative humidity has often fallen to 35%,
with an average close to 40%. A couple of my phals and a couple of my catts
have succumbed to this. Fortunately, most of the catts and phals, and all
of the dends, survived. And the surviving catts especially are thriving,
and the dends are growing well. Some of the phals still seem to be sulking,
but they've not shown since of decline.

And the dends I repotted today are still underpotted. The second nobile
type dend has no keikis, but it has two new pseudobulbs and a surprising
number of new roots. It seems to me that if it is doing this well in moss
in my environment, coir also ought to serve it well. In a sense, I am
letting my plants tell me that they are happy in a moisture retaining medium
in the growing conditions I can provide at present. But I expect that when
I get my growth chambers built, so I can keep humidity up in excess of 80%,
I may have to repot in CHC or even rock.

Thanks,

Ted