Did you know there are more than 30,000 orchid species, and at least 200,000 hybrids? Orchids, which are of the family Orchidaceae, thrive in environments from the arctic tundra to the equatorial tropics. But the largest numbers are found in the tropics.
You’ll find our orchid garden in the heart of Hawaii Tropical Botanical Garden, where there are always lots of species and hybrids blooming. And throughout our Onomea Valley garden, you’ll come across orchids growing epiphytically on trees, just as they do in their natural environment.
An epiphyte is a plant that grows on another plant but is not parasitic. Orchids and other epiphytes, such as many ferns, bromeliads, and air plants, grow on tree trunks in tropical rainforests. They get their moisture and nutrients from the air, rain, or debris that accumulates around them. It’s a thrill to come around a corner and see sprays of colorful, exotic orchid flowers blooming from the trunk of a tree.
Once you’ve encountered a few of those, you might understand how people become orchid fanatics. Susan Orlean’s best-selling book The Orchid Thief (also made into the movie Adaptation) is a fascinating—and true—story about a man and his orchid obsession.
There are primarily two categories of orchids.
- Monopodial orchids have a single, upright stem with leaves that grow opposite each other. The flower’s stem rises from the base of the uppermost leaves. Orchids of this type include the phalaenopsis and vanda.
- More common are sympodial orchids, which grow horizontally and send out new shoots from the rhizome. This type includes cattleya, cymbidium, oncidium, and dendrobium.
Considering taking on an orchid as a houseplant? Here are some tips:
Some orchids, such as phalaenopsis and paphiopedilum, are native to the humid tropics and like their daytime temperatures from 73 to 85 degrees, with 80-90 percent humidity. They prefer an east or southeast window.
Cymbidiums and dendrobiums are warm-climate orchids that like average temperatures of 55 to 70 degrees, steady moisture, and good air circulation. Put this type of orchid in a south-facing window, though during the hottest days you may need to give it a little shade.
Cattleyas and some oncidiums like their days dry and relatively cool. They can survive a long, dry season with temperatures of 80-90 degrees followed by a rainy season. They need a lot of light and do very well in a sunny, south-facing window.
Masdevallia and epidendrum are high-altitude orchids that grow in cloud forests where there’s an average temperature of 60 to 70 degrees and high humidity. They prefer filtered light.
Watering an Orchid
Never overwater orchids because too much water will cause an orchid’s roots to rot. One method is to try to water an orchid the day before its soil is dry. If you need to check, insert a sharpened pencil into the soil—if the plant has enough water, it will darken from the moisture. A more straightforward method is to stick your finger into the plant and see if it feels wet. When you aren’t sure whether it needs water yet, wait one more day.
It’s best to water in the morning, so there’s time for the water to evaporate on the orchid’s foliage and crown. Set the plant in a sink, use lukewarm water, and water for about 15 seconds. Make sure the whole plant gets water. Then let it drain for at least 15 minutes, so the plant does not stand in water.
It’s essential to feed your orchids regularly. Experienced gardeners use a 20-20-20 fertilizer. If you use a different type of fertilizer, make sure it contains little or no urea. Growers suggest fertilizing your orchids “weakly, weekly,” meaning it’s best to apply a diluted fertilizer (1/4 the recommended amount) every time you water (weekly), rather than the full amount just once a month. Never apply fertilizer to a dry plant; water it first.
For more information about how to care for orchids, here are some good reference books.