Click on a species below to see specific instructions
Flowering Varies with species
Care Average to difficult
The genus Odontoglossum is a large one, containing approximately 300 species. Botanists have tidied up the genus by moving some of the species to the genus Rossioglossum, but these are still commonly called odontoglossums.
The exquisite inflorescences of these plants are produced from the bases of the flattened pseudobulbs, and are usually erect and arching. The flowers are often large and showy, and come in shades of white, yellow, or green, marked with purple or brown blotches.
Temperature and Humidity Night temperatures of 52 to SS F and day temperatures of 65 to 70 F are ideal. However, plants in prime condition will tolerate a wider range, from a low of 45 F to a high of 90 F, for several days. High temperatures tend to prevent the flowers from opening properly, particularly the lip of Odontoglnssum crispum. Evaporative coolers installed in greenhouses in warm climates increase the chances of raising odontoglossums successfully.
To maintain cool and humid conditions in the greenhouse, water under the benches most mornings and, on bright days, water the leaves (but just enough so that they will be dry by nightfall). This scheme is one way to prevent red spider mites, a microscopic culprit that damages foliage and flowers.
A humidity of 65 percent is ideal, but odontoglossums are surprisingly tolerant of moderately lower or higher levels.
Light Odontoglossums require between 1,500 and 2,000 foot-candies of light. The maximum light permissible results in faint red streaks in the leaves. They may be raised in maximum light, which results in improved flower substance, when provided with cool temperatures and plenty of air movement. In the house, an east-facing window is best. During the frost-free months, set odontoglossums outside in a breezy spot with full open light but no direct sunlight.
Air Movement Odontoglossums thrive in an atmosphere that is fresh and buoyant from the use of fans, ventilation and misting.
Watering The frequency of watering depends on the potting mix and ventilation. Odontoglossums require lots of moisture when rooted in a free-draining mix, but expect decreased vigor if the mix is allowed to remain soggy. Periodically, collect rain water and use it to rinse fertilizer salts that accumulate in the mix. Excess fertilizer causes leaf tips to brown.
Fertilizing Nourish Odontoglossums in bark mixes with 20-20-20 fertilizer diluted to one-quarter to one-half of the recommended strength.
Light Medium to bright
Temperature Warm to cool
Flowering Varies with species
Care Easy to difficult, depending on species.
PHALAENOPSIS-TYPE DENDROBIUM hybrids are derived from Dendrobium phalaenopsis (syn. Dendrobium bigibbum). Commonly referred to as den-phals, they are among the easiest of orchids to grow under most conditions. These evergreen orchids reward the beginner with sprays of vividly colored long-lasting flowers in exchange for minimal care.
Arching inflorescences are borne on upright, cylindrical, 2- to 4-feet-tall pseudobulbs, which are slightly swollen at or above the middle. New growths develop from "eyes" near the base of the pseudobulbs and sometimes higher near the leaf joints. Somewhat-leathery, 3- to 6-inch-long leaves clothe the upper half of the pseudobulbs, and usually remain for one to two years. The number of flowers borne on an inflorescence increases as the plant matures. First-bloom seedlings often bear one to five flowers per spray; mature plants can produce 20 or more flowers per cane on each of many canes. Individual flowers last six to eight weeks and provide color for several months each autumn. Den-phal flowers, typically round and flat, with overlapping petals and sepals, range in color from pure white to deep plum and shades and hues in between. To prevent distorting the flowers' orientation, avoid moving or turning specimens once inflorescences begin to emerge.
Temperature and Humidity Den-phals thrive under a broad spectrum of temperature and light combinations. The recommended temperature range is between 50 and 90 F, but temperatures a few degrees higher or lower are acceptable and produce no detrimental effects. A relative humidity of 50 to 60 percent is optimal. In climates with lower humidity, mist the plants on hot, dry days. Avoid excessive water on the leaves and in the crown of the plants during humid and cool weather to prevent crown rot and fungal problems. Fans which keep the air moving without causing excessive chilling or drying keep the foliage dry, and also help remove heat from the leaves during hot weather.
Light Direct filtered sun is essential for flowering, but provide 30- to 70-percent shade during midday. Bright light will generally encourage flowering, provided excessive leaf temperatures are avoided. Although phalaenopsis-type dendrobiums can be grown under artificial lighting, this practice is not recommended due to the plants' height.
Watering The moisture needs of these orchids are similar to those of cattleyas. Thoroughly soak the potting medium, then allow it to dry out before watering again. Watering twice a week is generally adequate with properly potted plants in most climates. In winter, watering frequency may be reduced if the plants take longer to dry.
Fertilizing Apply a balanced fertilizer containing minor elements on a regular basis. When using inorganic media it is especially important to provide an adequate mix of nutrients, including minor nutritional elements. This is important since little nutrition is provided by the decomposition of the potting medium.
DENDROBIUM NOBILE AND RELATED species are native to Burma, India, Thailand and Indochina. Here they grow on trees, from the lowlands up to the cool highlands of the Himalayas at elevations of 4,000 feet. The species and their hybrids are extremely hardy, surviving temperatures ranging from warm to hot as well as enduring freezing conditions in some locales. If kept dry, these species and hybrids will survive winter temperatures of 37 to 39 F and flower around April.
Temperature and Humidity For differentiation of flower buds, it is important to expose plants to low temperatures. The pseudobulbs, which grow from spring through summer and mature in the autumn, require approximately one month of low night temperatures. Therefore, in the autumn when it becomes cool, do not rush to bring plants into the greenhouse, unless a freeze is forecast. Leave them outside to cool, and they will bloom better.
When in full bloom, flowers will last longer if the plant is placed in a cool, dry spot away from any draft and out of direct sunlight. A night temperature of 40 to 50 F is ideal. Water the plant enough to moisten the surface of the medium once every five to seven days during the warmest part of the day. The medium should dry before evening.
Light Small plants require no shade during the winter. However, 30- to 40percent shade is needed from late spring through autumn for healthy growth. Medium- or flowering-size plants do not need shade any time (unless the leaves begin to burn). Full sun promotes vigorous growth.
Where summer breezes are minimal, provide 30- to 40-percent shade during those months. If ventilation is inadequate in the greenhouse during the flowering season, buds will be damaged, and flowering will be poor. Therefore, 30- to 40-percent shade is recommended from the time flower buds appear until the end of the flowering season.
Watering When temperatures begin to rise in the spring, gradually start watering. In the summer, when temperatures are high and sunlight is strong, water almost every day to keep the plant from dehydrating. In late September, when temperatures begin to fall, gradually reduce watering. When the night temperature falls below 50 F, water only enough to keep the canes from shriveling; once a week should be adequate. When night temperatures fall below 40 F, keep the plants dry. In a greenhouse in which night temperatures are kept above 60 F, water lightly when the plants are dry. It is important that the medium surface is dry by evening.
Fertilizing A low-nitrogen fertilizer is ideal for flowering specimens. Discontinue fertilizing after early August to guarantee many flowers. For small plants grown without supplemental heat, and where night temperatures fall below 45 F in winter, apply fertilizer high in nitrogen when night temperatures rise to about 50 F (March or April). If night temperatures in winter are above 50 F, fertilize in January. The easiest way to fertilize small plants is with time-release fertilizers that are effective for more than six months. Do not use timed-release fertilizers on flowering-size plants; they may cause overfertilization.
Temperature Intermediate to warm
Flowering Any season; most species spring to summer
Vandas are some of the most popular cultivated orchids. The broad spectrum of their flower colors includes purple, brown, yellow, white, red, and blue-colors that have been mixed in fantastic combinations and patterns by hybridizers. The flowers are large and long-lived, and often appear more than once a year. They are produced from the points where the leaves join the stem.
Vanda plants have an interesting shape; the thick upright stems bear opposite ranks of leaves nourished by a tangle of aerial roots. As with the other monopodial orchids, all new growth takes place at the top of the plant. Some species grow very tall-up to 6 feet-but you can keep them at a manageable size by topping them when they get too tall.
Temperature and Humidity Vandaceous orchids thrive when the temperature during the day is 65 F or higher and night temperatures are not lower than 55 F. Warm temperatures and bright light promote active growth year-round. These orchids tolerate long periods of hot weather and short periods of cold. Some vandaceous plants can withstand temperatures as low as 38 F for two to three hours, suffering damage to root tips and flower buds, but not the plant itself. Humidity around 80 percent is appropriate on hot sunny days.
Light Vandaceous orchids require strong light. Provide full morning sun when possible. Semi-terete and terete types can be grown in full sun all day in tropical areas where the humidity is high. Strap-leaved plants need additional protection during the hottest part of the day.
Air Movement In the greenhouse, under summer sun, vigorous air movement from a fan is important to keep leaf temperature down and avoid cell damage from heat. For more open conditions - outdoors, in shade houses or lath houses - the natural breeze will balance light, temperature and moisture for healthy growth and flowering. It is important to restrict air movement under colder temperatures.
Watering A high daytime humidity is essential, especially on sunny days, and vandaceous plants outdoors may need watering and misting several times daily during the growing season when the sun is bright. Somewhat less watering is required indoors, although on sunny days plants should be misted once or twice. Limit watering during cooler weather, on cloudy days or after repotting.
Fertilizing Vandaceous orchids require copious quantities of nutrients. Give plants in the greenhouse a solution of a complete fertilizer, such as 20-20-20.
Light standards: bright; miniatures: medium to bright
Temperature Standards: cool; miniatures: cool to intermediate
Flowering Variable; peak in early spring
Substantial, long-lasting cymbidium flowers are as common in flower shops as cattleya flowers. The cymbidum's flower colors, which include all but the blue part of the rainbow, are often combined in lovely patterns. Imagine, for example, a pistachio green flower with a scarlet and white lip. The individual flowers are popular for corsages and when left on the plant last between 8 and 10 weeks.
Cymbidium hybrids fall into two main groups, standards and miniatures. Standard cymbidiums bear flowers between 3 and 5 inches across and grow up to 3 feet tall. They require bright sunlight and very cool night temperatures. Along the California coast, where these requirements are easily satisfied, standard cymbidiums are considered low-maintenance outdoor plants.
The flowers of miniature cymbidiums are between 1 and 3 inches in diameter. Although they are stilt too large to be considered true miniature orchids (which are generally less than 1 foot tall), their1- to 2-foot maximum height makes them more manageable. Although many miniatures will produce flowers in warmer temperatures than will standards, their high light requirement still makes them greenhouse or outdoor plants.
Watering Water cymbidiums thoroughly to avoid the buildup of fertilizer salts. Cymbidiums are native to monsoon areas, so they require ample water during their summer growing season. This does not mean that during the cool flower season the plants go dormant. Pot size and coarseness of the mix dictate the frequency of watering. A guideline: Water once a week, more frequently during warm weather, and less often in cool or wet weather. Overwatering will cause roots to rot.
Fertilizing The ideal feeding program is dictated by the seasons. Provide a balanced formula (20-20-20) all year long, supplementing with nitrogen in summer, to speed growth. Plants in organic mixes, such as fir bark, require more frequent feeding during the growing season. Apply the fertilizer one-half strength every two weeks rather than once a month. Toward the end of the growing season (June), discontinue the nitrogen supplement to promote the initiation of inflorescence.
Light Low to medium
Temperature Most cool, some intermediate
Flowering Varies, most spring to sunnier
Care Average to difficult
The showiest parts of a masdevallia flower are the sepals; in this genus the petals are tiny structures nestled in the center of the flower. The sepals join at the base and narrow toward the tips, often into long tails, making the flowers of some species resemble kites. Most forms have distinctly triangular or tubular flowers. The flower colors include pure white, green, and brownish black, but tile most popular species are orange to red. Flower sizes range from about 1 inch to as long as 10 inches, Some are pendent, others are erect.
Masdevallias are true cloud forest orchids, requiring constant moisture. They have no pseudobulbs—the fleshy leaves are borne on tiny stems sprouting from small rhizomes—and thus cannot endure periods without water. Most are from high elevations (between 6,000 and 12,000 feet) and need cool conditions, but a few species will grow in intermediate temperatures.
Although masdevallias need lots of humidity, excess water on the plant causes a fungus infection that rots the leaves where they join the stern. Don't compensate for low humidity with frequent mistings or waterings.
Light Masdevallias usually grow In relatively shaded areas in the forest. In cultivation, about 1,000 to 1,400 foot-candles of light is adequate. The leaf color should be medium + to light green. Too much light quickly produces yellow, leaves.
Watering Because masdevallias are relatively small plants potted in small pots, it is necessary to water often. Frequency depends on time of year and type of container and medium, usually ranging from two to three times a week in the summer to about once a week in the winter. Keep the medium moist but not sopping wet. Flush water through pots to insure thorough wetting. Overwatering does not make up for lack of humidify and will cause root rot.
Fertilizing Masdevallias are not heavy feeders. Apply one-half strength of a balanced fertilizer once of twice if month. Overfeeding may cause leaf-tip burn.
(Shelldance 20-20-20 Professional Orchid food is great!)
Light Low to medium, depending on species
Temperature Intermediate to cool, depending on species
Flowering Generally fall to spring
Care Very easy to difficult
Paphiopedilums differ from other orchids in both the appearance of the plants and their flowers. One of the most obvious features that sets the flowers apart is the lip, which is modified into a pouch like a cup. This pouch suggests the name "lady's slipper,"a common name applied to paphiopedilums and their relatives in the subfamily Cypripedioideae.
Temperature and Humidity The green-leaved types ideally require a minimum night temperature around SO to SS F, while the mottled-leaved types need 60 to 65 F at night. Day temperatures should range between 70 F and 80 F, although short periods of moderately higher or lower temperatures will not injure the plants. The humidity should be moderate, between 40 and 50 percent during the day.
Light Paphiopedilums enjoy medium light intensity, requiring 800 to 1,000 footcandles throughout the year for optimum growth. Avoid direct sun, except in the early morning. In the home, move plants back from the window at the height of the noonday sun or, ideally, grow them behind a sheer curtain.
Watering Although paphiopedilums are sympodial orchids, they do not possess pseudobulbs and hence, like phalaenopsis, must have a regular and constant water supply. This will entail keeping the medium moist but not wet, a technique with which beginners will have to experiment in order to perfect. Water early in the day so that the foliage will dry before temperatures drop at nightfall.
Paphiopedilums typically need watering every five to seven days, but individual conditions require some variance. The potting mix, the humidity surrounding the plants and weather conditions all affect the rate at which plants dry and thus require water.
For those growers using bark as a potting medium, it is extremely important not to permit the plant to dry completely because the bark is then difficult to rewet. Water will channel through the dry mix leaving most of the pot dry. When this happens, submerge the whole pot and mix in a pan of water until moisture has been restored to the pot.
Fertilizing Feed plants in fir bark with a high-nitrogen fertilizer (30-10-20 or 3010-10 ratio) at half of the recommended strength: Fertilize greenhouse-grown plants three times and then apply plain water for the fourth watering to leach out any salts that have accumulated. For home or windowsill growing, alternate fertilizer and plain water. Plants grown in some of the more complicated mixes consisting of rock, peat, oak leaf mold, etc., should receive fertilizer at a more reduced strength because some of these elements may provide.
Light Low to medium
Temperature Colombian: cool; Brazilian: intermediate
Flowering Most summer to fall
Care Average to difficult
Miltonias are the wellknown "pansy orchids," plants with large flat flowers that look very much like the flowers in the popular genus Viola. Some miltonia flowers are lightly fragrant. A part of the subtribe Oncidiinae, the approximately twenty species of Miltonias are distinguished from their relatives in the Odontoglossum, Oncidium, and Brassia genera by differences in their flowers-very minor differences in some cases. When not in flower, the thin leaves and flattened pseudobulbs of miltonias are so similar to those of species in related genera that it is sometimes difficult to tell the plants apart.
There are two types of miltonias, differing in flower form and cultural requirements. The ones with the flat pansy-type flowers grow in high, cool areas of Colombia and nearby countries. These are now technically grouped in the genus Miltoniopsis.
Flower colors in this group range from white to pink, with splotches of crimson to magenta. These plants do best in light intensities in the 1,000 to 1,500 footcandle range, about the same intensity required by phalaenopsis plants. They need cool night temperatures and are sensitive to daytime temperatures over 80° F.
The flowers of the other type, the Brazilian miltonias, don't resemble pansies; they look more like odontoglossums, blooming in shades of yellow and green marked with brown, purple, or red. They prefer medium light intensities (I,500 to 3,000 foot-candles) and slightly warmer temperatures than do the Colombian species.
Miltonias of both types sunburn easily. If the plants are getting enough light, the leaves will be light green, lighter than you may think is healthy if you compare them to most other plants. A slight tinge of pink indicates that the plants are receiving as much light as they will tolerate.
Fertilizing In fir bark culture, administer 30-10-10 fertilizer weekly at the rate ½ teaspoon per gallon of water. Because pansy orchids are not deciduous, continue to feed them during the winter at the rate of ¼ teaspoon per gallon, but only if the plants need water.
Watering Despite the presence of their water-storing pseudobulbs, miltonias can't withstand periods of dryness. Water them as you would cymbidiums, keeping the medium moist-but not soggy-at all times. A potting mix of fine fir bark, amended with sphagnum moss, perlite, and a little charcoal provides a good balance of water and air for these moisture-loving plants. If the new leaves emerge pleated, the plant is not getting enough water. Increased watering won't flatten them out (they will always look like accordions) but the next leaves should be smooth. The flowers of the Colombian species last from two weeks to two months on the plant, but wither quickly when cut. Brazilian miltonias make fine cut flowers.