Background

Orchids once had a reputation for being both expensive and difficult to grow. Thanks to more efficient production processes and the development of low-maintenance hybrids, several varieties of orchids today are not only reasonably priced, but also resilient enough to survive for years on your window sill if given the kind of consistent, routine care you would provide any flowering houseplant.

Most orchids commonly grown as houseplants are epiphytic as opposed to terrestrial plants. That means they grew in nature on trees or rotting logs, with their roots dangling in the air from which they obtain moisture and nutrients. The epiphytes themselves can be further subdivided into two broad groups- sympodial orchids (such as cattleyas) that grow through creeping rhizomes, and monopodial orchids (such as vandas) that spread by continuously producing new lengths of stem at the ends of older growth.

How to Care for Orchids

Despite minor variations of the kind that always exist between plants of different species, epiphytic orchids share several preferences that can be traced back to their common, tree-dwelling origin. These general preferences, many of which also apply to terrestrial orchids,* provide the keys to proper care. Here's a quick rundown of the basics:

Potting Mix.  Since epiphytic types are tree-dwelling plants and terrestrial types grow in very loose, moist, humus-rich soil, it should come as no surprise that conventional garden soil just doesn't work for orchids. Instead, they need to be grown in a light, bark-based potting medium made especially for orchids. 

Most orchids flower more freely when their roots are a tad cramped, so repot them only when growth shows signs of abating. When it's time to re-pot, simply move up to the next larger sized pot (increasing pot size as little as possible) or divide the plant and re-pot the divisions in separate small containers.

Light, Temperature and Humidity. Most houseplant orchids prefer bright, but filtered light, such as that from an east or west-facing window. Outdoors, plants should be placed in filtered light, protected especially from intense afternoon sun. Rotate plants ¼ turn every week or so to prevent plants from leaning toward the light.

Most orchids thrive best in a temperature range of 50 to 60 degrees F on the low end and 70 to 80 degrees F on the high end. Daytime temperatures of approximately 70 degrees F in summer and 60 degrees F in winter will suit most types well, as will slightly cooler nighttime conditions year round. On especially cold winter nights, move your plant further away from the window to avoid exposing it to excessively low temperatures.

While actively growing in spring and summer, most orchids require very humid conditions. To supply the ambient moisture they need at this time, set pots of indoor plants on trays of moistened pebbles or gravel, making sure that the water level of the tray stays safely below the drainage hole at the bottom of the plant's container. Better yet in warm, humid climates, let your plants spend the summer outdoors.

Watering. For most types, you'll want to keep the potting mix evenly moist (but never saturated or soggy) at all times. Watering whenever the plant's pot feels lighter than normal is a good rule of thumb to follow: This indicates that the potting mix has dried out almost completely, and will automatically encourage you to water more often in summer (when the plant is active) and less often in winter (when the plant needs to rest).

Note: Corsage and Pansy orchids- cattelya and miltonia respectively- are exceptions to the "evenly moist" rule: They should be watered when the surface of the potting mix feels dry to the touch.

Feeding. Feed indoor plants every time you water with a water soluble orchid food. Use a high-nitrogen formula during the spring and summer growing periods, as the bacteria in decomposing bark uses a lot of nitrogen, making it unavailable to plants. In the fall and winter, switch to a lower nitrogen, high phosphorus plant food to encourage blooming.

Insect and Disease Control

Though they aren't particularly attractive to insects, orchids can occasionally be visited by insects common to most houseplants, including aphids, mealybugs, scale, spider mites, thrips and whiteflies. Control these as they occur with insecticidal soap, neem oil, pyrethrin or other insect spray.

The singlemost disease concern is root or crown rot, which can occur in poorly drained conditions or if excessive watering occurs. If soft, dark, mushy tissue develops, it should be cut out or removed with a sterilized knife. The wound should be treated with sulfur powder or other fungicide indicated for that purpose. Correct drainage problems, and water sparingly. Leaf spot, powdery mildew and other foliar fungus diseases can be prevented and controlled with a fungicide spraying program.

Propagation

The most common form of propagating orchids among home growers is division. Sympodial orchids (those that grow laterally by rhizomes) are easily divided. Make sure the plant is large enough that, when divided, each new segment will consist of at least 3 healthy shoots, or pseudobulbs. Simply use a sharp, sterilized knife to separate sections. Plants make take 2-3 years after dividing to rebloom.

More about Orchids

To give you a small sampling of what's available, we've provided brief descriptions and tips on care for eight popular orchids, each of which is noteworthy for ease of maintenance, exceptional beauty or both. Orchids that are frequently recommended for beginners are italicized.

Cattelya. Hybrids of the "Corsage Orchid" are known for producing wide (6" across), waxy blooms in colors ranging from deep lavenders to pristine, snowy whites. Due to their need for high humidity (50-60%!) and well-regulated warmth, most cattleyas are best grown in a greenhouse environment. If you attempt to grow one indoors, however, opt for a south-facing window to insure that the plant receives sufficient light and heat.

Coelogyne. Species within this genus are typically excellent choices for beginners, especially c. christata, which features elegant white flowers with a narrow splotch of golden yellow at the lip. Coelogynes tend to be free flowering, and most can withstand somewhat cooler conditions than other orchids (winter minimum temperature of 50 degrees F). Grow indoors or in a cool greenhouse, providing a well-lit situation and winter rest to foster timely, robust blooming.

Cymbidium. The miniature hybrids of this popular terrestrial orchid are not only easy to care for, but also much more manageable than larger orchids owing to their limited size and free flowering, but compact blooms. They can be grown in the greenhouse or indoors with no winter rest. Give them full light (and a minimum temperature of 50 degrees F) in winter, but provide shading from direct Sun in summer. Re-pot container-grown plants every other year in a light, bark-based potting mix to help ensure continued blooming.

Miltonia. The "Pansy Orchid" derives its name from velvety, medium-sized blooms that resemble the pansy's in form. Orchids from this genus are suitable for growing in a greenhouse (the most reliable option) or in a warm room indoors. If growing indoors, be very careful to avoid exposing the plant to cold, wet conditions or to wide fluctuations in temperature. Requires no winter rest and prefers medium light and temperatures in the 55 to 70-degree F range.

Odontoglossum. The "Tiger Orchid" is so named for its boldly striped blooms. Most species within this genus require good light, high humidity and a period of rest in winter. O. grande is an "easy" orchid noted for its exceptionally large blooms, which extend six inches across.

Paphiopedilum. Also known as the "Lady's Slipper Orchid," species within this genus have an exaggerated pouch (hence the common name), attractive, arching foliage and medium sized (2-4" wide) blooms. Paphiopedilums are terrestrial orchids. They require no winter rest period, and most prefer low to medium light and a temperature range of 55 to 70 degrees F.

Phalaenopsis. The "Moth Orchid" offers long sprays of bright, cheery blooms on gracefully arching stalks. Flowers tend to be flat-faced, and vary in size depending on the specific species in question. These epiphytes prefer low to medium light, relatively high humidity and warmer than normal temperatures (60 to 85 degrees F for most types). If grown indoors, place the plant's pot near an east or west-facing window and provide some sort of screening from full, direct sun.