CHOOSING ORCHIDS TO GROW IN THE HOME
Dr. Leonard Perry, Extension Professor
University of Vermont
Orchids have surpassed the poinsettia in many parts of the country as the biggest selling flowering potted plant. There are many types though, some quite expensive, with varying growth requirements. Knowing these, together with which are easiest to grow indoors, can save you money and disappointment from false expectations.
First, decide what you want from an orchid plant. If you just want the blooms, then your desires and budget are the main limitations. Since many orchids bloom for a long period under the right conditions, weeks or even months, this may be all you want. If you want to keep the plants growing indoors as houseplants, blooming in future years, then your choices begin to narrow.
Orchids can be grouped in several ways-- keys to their requirements, and so to your success. Some are terrestrial, or growing in soil, such as the Jewel Orchid (Ludisia) and some Lady Slippers (Paphiopedilum). Most though are epiphytic, or growing on bark or similar material. These get their water and nutrients from whatever falls on them or their aerial roots. They are often adapted to high humidity, so fair poorly in dry homes.
The main grouping to be aware of indoors is by temperature requirement. This comes from the altitude they grow naturally in the tropics. Those nearest sea level have the warmest and most consistent temperatures, and so are the ones best adapted to similar conditions usually found in homes. These include some of the larger Dendrobium species, Phalaenopsis or Moth Orchids, and Vanda Orchids.
Intermediate-growing orchids are from higher altitudes, where night temperatures fall to 60 degrees during the winter. Many of these can also be grown indoors, as long as high levels of indirect light are provided, high humidity, and cooler temperatures during winter months. If you keep you home cooler during winter, perhaps you may wish to try some of these such as the many Cattleya or Corsage orchids and the many hybrids, Laelia, many hybrids of Laelia and Cattleya, Epidendrum, and Lady Slipper or Paphiopedilum.
Cool-growing orchids are from even higher altitudes, where night temperatures reach 50 degrees during the winter. Cymbidium and Oncidium are an example of these, and require quite cool winters with high humidity and high light.
Orchids may differ in their temperature needs, but all grow best indoors
with sufficient light and humidity. Full sun in winter, such as from
a south window, is best. Orchids may also be grown under artificial
lights, about a foot above plants and on for about 16 hours a day.
During summer, put plants in indirect light. Too much light and leaves
become light green or yellow,
perhaps even brown. Too little light and leaves may be darker green, slender and twisted; new growth may be horizontal not upright; and plants may not rebloom.
Humidity should be increased from the often 10-15% often found in homes in winter, to around 50-75% around the plants. This may be done by placing plants on a tray of pebbles kept wet, by misting leaves daily or more often (just make sure and don't mist furniture and walls!), or by placing plants near a humidifier. If temperature and light are right, but humidity is too low, plants may not bloom and may grow poorly.
Keep in mind that many orchids only bloom once a year, even under the right conditions. Some such as Odontoglossum may bloom every 10 months, others such as Phalaenopsis twice a year.
Orchids are quite a large group, and in fact the Orchid family is the largest of flowering plants. There are over 1000 genera, 25,000 species, and 100,000 hybrids. So the above recommendations for main genera (such as Vanda and Cattleya) are general, and there are often wide variations in cultural needs depending on species. Follow these basic rules, though, and you have a good chance of success with the basic orchids you commonly may find for sale.