Too Cold for S/H?
 

I am considering switching my cymbidium insigne and my NOID miltoniopsis to s/h during growth season.

My growing conditions:
* Winter temps: high 60s in the day (if no sunshine) & 50 or possibly a little lower at night. If there is sunshine, it could go to 75-90 in the day.
* Low humidity
* Some air movement as there is an air vent over the orchids area with high ceiling. Air flow is never heavy enough to move any of the orchids.
* Grown indoors throughout the year in an eastern facing window.
* Currently potted in terrestrial mix.

Before I move them to s/h later, I was curious to know if my winter temps are too cold for s/h. I do not plan to put them on a heating mat. Thanks in advance the advice!

Susan

There is no such thing as "too cold for S/H".

What you have to consider is whether the open, airy volume of medium, and its enhanced evaporation, will lead to temperatures in the root zone that are too cool for the specific plants.

I the cases of cymbidiums and miltoniopsis, I doubt it.

Some use semi-hydroponics - using clay pots standing in trays of water - as a way to intentionally drop the root-zone temperature in order to "stretch" the range of growing conditions to cooler plants.

As Ray has said, sometimes this is a great method to intentionally drop the root zone temperature and I'm planning to try something like Ray mentiones with my Masdies this summer.

I've just yesterday spotted a problem with a Phal that was doing wonderfully in S/H but yesterday I noticed the roots have rotted suddenly. I suspect temperature was the problem as it was something I was a bit worried about with this one.

However that is Phals, which like the warmth. I agree with Ray that Cyms should be fine. I'm not so sure on Miltoniopsis because while they are meant to be cold growing mine seems to be enjoying Phal type temps, but maybe that's just this one plant.

Thank you Ray & Rosie for your quick replies!