could very well be lava rock in the mix - it's very porous so aerates the mix well, as well as having some moisture retention - I usually add a fair amount of perlite and/or pumice to my mix - as well as some styro pnuts.

Different people use different media to suit their growing conditions. For the most part, cyms don't seem to be extremely fussy as long as the mix retains some moisture, but drains well.

Since yours is spiking, it would seem the culture you have provided so far is making your cym happy :)

In warm places many people grow them right in their gardens, in soil. I had mine in a soiless mix, which is often recomended, but My neighbour has hers in potting mix and I noticed that hers look beter than mine, so I switched. They imediately improved. I do like to add a fair bit of sand and pearlite. I think it keeps it more airy.

Cymbidiums ARE NOT terrestials and will not do well in potting soil of any kind! They need an open, well draining mix. Many are available on the market and this Forum has given many combinations and recommendatiions. Most recent is the "Repot medium question" thread of a couple of days ago.

CL

The first time I re potted a cymbidium, the book I have said to mix leaf mold, sand, bark and peat moss. It worked beautifully. The only leaf mold I had were some rotting maple leaves. I also added a little compost from the compost pile, because the book refered to it as "compost" and I mis understood. The cymbidium didn't care. It bloomed beautifully.

I just checked the internet. I beg to differ. Cymbidiums are terrestrial.

Hmm whether they are terrestrial or epiphytic is very dependent on the background. For example, canaliculatum is definitely epiphytic and devonianum is decidedly terrestrial. Problem is that most of what we grow today are hybrids and so a mix of different species. In one sense it is correct to think of them as epiphytic in the sense that the media to grow them needs good aeration and drainage. On the otherhand, I see many people grow them directly in the ground where it never freezes as long as there is a high drainage factor. Here in Hawaii I've seen fields of them in the aa lava (very porous lava). Summary: Do not think of them strictly in terms of terrestrial or epiphytic unless they are species or primary hybrids from the species.

Very true. I have been reeding up on them, and some are terrestrial, but not all.

Well, I am very glad my thread has prompted such discussion. To everyone who has taken the time to look and reply to me, I say thank you, and I will post some pictures of the flowers, if they open completely.

please do! Cybidium are one of my absolute favourites!

Bob,

What is your source for saying devonianum is terrestrial? :scratchhead:

In "The Manual of Cultivated Orchid Species" by Bechtel, Cribb and Launert, as just one source, Cym devonianum is described as "An epiphytic or lithophytic plant...". No where does it say terrestrial and the photos I have seen from Keith Andrews or Ron Parsons of plants in the wild have been in the trees. Yes, eventually the plant may become so heavy as to cause the limb to fall, resulting in the plant ending up on the forest floor still attached to the limb. But that does not make it a terrestrial by orchid description.

:twocents:
CL