Clay pots?
 

Can I do semihydro with clay pots and hydroton sitting in a saucer of water or would there be too much evaporation?

Welcome to the Orchid Board!

There will be evaporation, and cooling. That might be beneficial if you're trying to grow a cool growing orchid.

For the sake of discussion, I wouldn't call what you're describing semi-hydro, since that term is most commonly used with a very narrow definition.

As for the potting technique you've described, if you practice an appropriate watering regimen, then your plants will do fine. The clay pot will wick up moisture if there's standing water in the saucer, so you'll probably find that you need to water more frequently if you're growing moisture loving plants. Another consideration is that the added evaporation by the clay pot will cool down the roots. Depending on your climate and growing conditions, this may be helpful (if it's hot and dry and your plants like it cool) or harmful (if it's cold and dry and your plants like to stay warm).

Well, I would call that semi-hydro culture, as it involves the use of an inert medium and a static reservoir of water/nutrient solution.

Such a setup definitely enhances the evaporation and cooling, with the degree of cooling determined by your ambient humidity and temperature.

Thank you for the welcome and the replies!

How much cooling does it provide? My grow room goes down to a low of 55 In winter. I do bring some plants into the main house in winter and could bring in others if need be.

Welcome VeggieGirl! That's pretty darned cool if you also add SH and a terra cotta pot into the equation. Better research the temperature range of the orchids you plan on doing that with, or ask if you can't find the info.

For example, a Phal wouldn't care for it at ALL. A cool growing Cymbidium would be fine.