Orchid Media

[Ray]

In another thread...

I live in southern Ontario, with warm to hot humid summers, cool to cold winters. I had a niveum cross that lived in live moss in a pot outside from half of may till September. It didn’t seem to like anypotting medium. No matter what I did I couldn’t make it happy. It grew a bit, but winters under grow lights and 60% humidity still didn’t make it happy. It never flowered and slowly withered away.

Orchids do not "like" or "dislike" a medium, what likely happened is that, in your growing conditions, the media you have used did not provide the conditions the plant needs. Most of the time, we tend to focus on the air:water ratio, but chemistry can play a role, as well.

Plus, there's the possibility that your attempts to move to different media were not well timed.

 

[TyroneGenade]

When I moved from IA to TN I repotted everything into aircone pots with a bark mix from Orchid Inn and the plants took off in the new medium. But I was growing in a small room with high heat and humidity. When I moved the plants went into a much drier, cooler basement and the plants began to languish. Perhaps the drier air was making evaporation and salt creep more of a problem? I just recently repotted everything into yogurt tubs (holes punched into the side 1 inch from the base so there is a water reservoir) with lava rock and again everything (but the Lycaste) is enjoying the change. A mini-Catt that has suffered in bark (never able to get new roots to survive) is doing splendidly. The Lycaste will go back into sphagnum in a basket suspended in a yoghurt tub where it seemed happier. I don't think the miracle was the lava rock so much as that lava rock provides better humidity and a more open mixture, and that this is what is needed in my cooler, drier basement conditions. I do have a niveum in lava rock and it looks very happy: nice new roots growing and big green (mottled) leaves.

I think if you are having trouble the way to go might be to buy several of the same plant and pot them all up in different mediums and perform a proper experiment to find out what medium or mediums work under your conditions. In Canadienne's case I think the problem might have been the move from outside to inside. This was likely a big change in humidity. As Paphs only grow new roots once a year, if those roots had died previously then moving to the drier air was a death sentence -- and it is remarkable how long it can takes a Paph to die even once having reached the point of no return.

I think an interesting question, for home growing, is what mediums do well under what conditions? What plants are the exceptions, i.e. don't like a particular medium even if it is the best medium for the conditions?