Cymbidium Care

Question

What's the word on growing sizable (6- to 14-inch pot) standard cymbidiums in Pro-Mix or similar media? Has anyone reported on doing this long enough to judge success? It would make sense that cymbidiums and zygopetalums would do okay in the mix, but I grow outdoors in summer in an area with frequent heavy thunderstorms, and worry that the roots would rot in this heavy a medium. I suspect that California data will not be very relevant to my southern Appalachian locale. —John A. Hyatt, PhD
 

Answer

I think larger cymbidiums will grow well in Pro-Mix and there are similar mixes currently in use in Europe and Japan. Zygopetalums do exceptionally well in Pro-Mix. But you need to water differently and add a wetting agent to the fertilizer.

Actually, the California growers often keep their plants too cold in winter to achieve the best results from this type of mix. I would think you would have few problems in your area in summer as roots rot when they are cold and wet (not warm and wet). In fact, I think you might be surprised with your results. The only caution I would add is to be sure that your local water is reasonably low in dissolved salts, as Pro-Mix is not easy to leach out when salts build up. You would be wise to feed at 1/4 label recommendation during the hottest months (July 1 - September 15) in your area, because Pro-Mix holds fertilizer better than more open bark mixes. —Andy Easton