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Controlled Growing Conditions (Continued)

Selection of Media depends upon relative humidity, species and type of pot. Left side, top to bottom, Spagnum moss, paphiopedilums mix, pea gravel. Right side, seedling mix, medium mix, coarse mix.

Media

Ideal media must have good even drainage, high nutrient content, resistance to rot, good air circulation and be inexpensive. To achieve these characteristics usually a blend of media is used. As a standard I use an equal blend, by volume, of fir bark, charcoal, and stone. The stone is typically washed graded pea gravel; when weight is a concern I substitute sponge rock (coarse perlite). I pour the mixture in a large tray and shake it to cause a gradient in the size of the pieces.

I line the bottom of the pot with pea gravel. Then start with the coarser mix at the bottom, and use a size gradient to the finer pieces as I fill the pot. In the top one inch of the pot I use a seedling mix (perlite, tree fern and fine fir bark). There are times that I like a slightly wetter mix. When planting ensifolium, using an unglazed pot, or a pot with side ventilation, I introduce up to 20% tree fern fiber to increase the water retention.

Light

The level of illumination is very important to the growth of Cymbidiums. Insufficient illumination will result in weakness and irregular growth of Cymbidium. Too strong illumination will damage the leaves and particularly in the variegated species, reduce the ornamental value by reducing the color contrast of the patterns.

During the summer months, if growing in a sunny location, the shading should be 50 - 70%. The higher mountain Orchids gorengi and faberi prefer slightly higher shade rates. During the winter season, shade can be reduced to 20 - 50%. Because of this "low light" environment, The Asian Cymbidium is an excellent candidate for growing under florescent lights, the only challenge being maintaining high humidity.

Some of the best examples of Cymbidium sinense were found inside the factory offices in a water bottling plant in China. Here, the Asian Cymbidiums were about 4-5 feet from banks of lights and that were illuminated for about 12-16 hours per day. The combination of high humidity, long hours of florescent lights, and a constant cross breeze gave them a good environment.

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This two-part article appeared in the American Orchid Society Magazine "Orchids" in July 1999 and August 1999. All photographs are copyright of Charles Marden Fitch 1999 and cannot be used without permission of him or the author.