Sophronitis in perlite

I'm getting ready to repot my Sophronitis orchids, which are currently growing in coconut husk chips. They seem to be doing fairly well since I've been watering them more often, but I have seen them grow better in the years past. It probably is that the medium is breaking down and the roots are not as happy any more. I think the timing is good, since Sophronitis show active growth in the fall and winter, before they flower.

I have read several posts on the internet that some growers have had success in growing Sophronitis coccinea and Dendrobium cuthbertsonii in perlite only. Since perlite is readily available at my nearby nursery, this technique is quite attractive to me. Additionally, perlite does not break down, since it is an amorphous volcanic glass. Moreover, perlite retains moisture well while also providing valuable air spaces, which is key to good orchid root health.

It appears that the growers using perlite use a semi-hydroponic water culture. Simply, this is letting the orchid pot sit in a shallow reservoir of water such that the perlite draws up water by capillary action (water creeping up due to water tension). As the moisture evaporates from the perlite, the reservoir replenishes the water. The added benefit of this method is that the evaporation decreases the temperature in the roots, which is benefitial to many cool growing orchids, such as Sophronitis, some Dendrobiums, Masdevallia, Dracula, and some Odontoglossums, to name a few.

I will pot up a tray of the Sophronitis orchids and the few Dendrobium cuthbertsonii that I have to test out this new technique. I'll post pictures of the repotted orchids once I finish this task. In the mean time, I have to decide if I will use clay pots or plastic pots. I want to use clay pots for the added evaporation, but the one major disadvantage of clay pots is the build-up of salts on the surface of the pots, which is problematic with poor water quality. Stay tuned.