Dr. Leonard Perry, Extension Professor
University of Vermont
Orchids are exotic, elegant, and romantic. That’s what makes them the perfect gift for your special someone on Valentine’s Day.
Orchids come in all colors except black (although there are orchids that are almost black), in all sorts of beautiful and bizarre shapes, and in a wide range of sizes. Although most garden centers carry reasonably priced, easy-to-grow varieties (mostly tropical species), in the natural world there are more than 20,000 species of orchids, growing in every type of habitat from tropical rain forests to the tundra and semi-arid desert, and on every continent except Antarctica. Orchids grow in all 50 states, even Alaska!
Since many homes are quite dry in winter, particularly those with forced-air heat, you’ll want to choose species that tolerate such conditions. Not all orchids grow in rain forests; some grow in areas with seasonal dry periods. Some of the more common are found among dendrobiums, oncidiums, and the corsage orchid (Cattleya). More uncommon for dry climates are Brassavola and some Aerangis orchids. Generally those that grow best in dry, indoor air include ones with seasonal growth, hard leaves, and “pseudobulbs” (a swollen stem area the plant uses for storage). Using a humidifier near plants, or placing them on a tray of pebbles, kept moist, will help most any orchid in dry indoors.
When buying an orchid, the plant should be securely rooted in the pot and have lustrous flowers and firm, succulent leaves and pseudobulbs. For those “epiphytes”— that grow naturally on the sides of trees, that get their nutrients and moisture from rain and air, which are the ones you’ll find growing in bark — fresh, white roots with green root tips also are a sign of a healthy plant. As with other flowering plants, buy orchids with some buds still left to open. Make sure flowers and leaves don’t have spots, which could be from poor culture or even disease.
Orchids are commonly grouped as cool, intermediate, and warm, based on the plant’s optimum night requirements (45 to 50 degrees F, 55 to 65 degrees F, and above 65 degrees F, respectively). For warm homes, consider the Dendrobium, moth orchid (Phalaenopsis), or Vanda orchids. The moth orchids grow under similar conditions to African violets, making them one of the best choices for growing indoors.
Those for intermediate temperatures, such as Cattleya and its hybrids, may need more humidity to grow well than is usually possible indoors. Cymbidum and Oncidium, while taking cooler temperatures in winter, also need high humidity and high light to grow best.
Some orchids may not bloom if the nighttime and daytime temperatures are the same. Consistently warm temperatures are good for leaf growth, but may suppress flower development.
Most orchids require relatively high light intensities and should be grown in an east or south window. However, a few will grow well under low intensity fluorescent lights. Insufficient light is the most common reason orchids don’t flower. If there is too little light, the leaves become a deep, lush green. With too much light, the leaves turn yellow-green.
Orchids vary in their water requirements. The tropical orchids, which mainly are epiphytes, should be grown in a very porous potting medium such as coarse fir bark or lava rock. Place these pots in the sink and run lukewarm water through them for about 15 seconds, then allow to drain for about 15 minutes. Terrestrial types, rooted in soil, require a well-drained growth medium. One of my favorite orchids, which is easy to grow in soil indoors in the north and lasts for many years, is the Jewel orchid (Ludisia). Another popular terrestrial orchid, easy to grow indoors, is the lady slipper (Paphiopedilum).
Watering and fertilizer frequency depends on orchid, and the medium in which they are potted. Most orchids growing in bark cannot survive prolonged drought and should be watered often. However, some require a “dry season” of six to eight weeks during which watering is reduced but not stopped. This “dry season” must occur immediately after the current growth matures and is often necessary to initiate future flowering. Some Dendrobium and Oncidium orchid species are in this group.
Orchids are affected by many of the same pests and diseases as other houseplants. Insects such as mealybugs and aphids can be controlled with water rinses and insecticidal soaps.
If you want to buy a potted orchid for yourself or for a gift, check online for local orchid growers or societies, or visit your local florist, greenhouse, or garden store. These can be great sources of information, as is the American Orchid Society (www.aos.org).
If all this culture sounds too much for you or your Valentine recipient, consider a cut-flower orchid you can find at florists. Protect it from cold on the way home, and from cold drafts once home. Keep away from direct sun and heat sources. Cut Cattleya should last for one week. Phalaenopsis, Oncidium, and Paphipedilum should last one to two weeks as cut flowers. Longest lasting orchids as cut flowers, often from 4 to 6 weeks, are Cymbidium orchids.