Phalaenopsis

Light is easy to provide for phalaenopsis. They grow easily in a bright window, with little or no sun. In overcast northern winter climates, a full south exposure may be needed.

• In a greenhouse, shade cloth is required to reach about 10,750-21,500 lumens (1,000-2,000 footcandles), depending on the plants.  
• Indoors an east window is ideal in the home; shaded south or west windows are acceptable
• Many types of phalaenopsis will grow well under artificial light. Use lightbulbs or LEDs of your choice that are about 1-2 ft (30-60 cm) above the plant and emit greater than 10,000 lumens per square yard/square meter. The lowest number of lumens for growth is about 2,000, though flowering may be poor.

Temperatures for phalaenopsis should usually be above 60 F at night and range between 75 and 85 F or more during the day. Although higher temperatures force faster vegetative growth, higher humidity and air movement must accompany higher temperatures, the recommended maximum being 90 to 95 F. Night temperatures to 55 F are desirable for several weeks in the autumn to initiate flower spikes. Fluctuating temperatures can cause bud drop on plants with buds ready to open.

Novelty phalaenopsis appear to flower at about any time if given sufficient light.

WATER is especially critical for phalaenopsis. Because they have no major water-storage organs other than their leaves, they must never completely dry out. Plants should be thoroughly watered and not watered again until nearly dry. In the heat of summer in a dry climate, this may be every other day; in the winter in a cool northern greenhouse, it may be every 10 days. Water only in the morning so the leaves dry and do not let water collect in the crown to prevent crown rot.

Humidity should be 50 to 80 percent. This can be provided in the home by placing the plants on trays of gravel, only partially filled with water so that the plants do not sit in the water. Air should always be moving around the plants to prevent fungal or bacterial disease, especially if high humidity or cool temperatures exist, In the greenhouse the humidity is best increased by use of a humidifier. Evaporative cooling increases humidity while cooling the air.

Fertilize on a regular schedule when the plants are growing, especially if the
weather is warm. Twice-a-month applications of high-nitrogen fertilizer (such as 30-10-10 are appropriate where bark-based media are used. Otherwise, a balanced fertilizer is best. When flowering is desired, a high-phosphorus fertilizer such as 10-30-20) can be applied to promote blooming. Some growers apply fertilizer at one-quarter strength with every watering; this is best for warm, humid conditions. With cooler or overcast conditions, fertilizer should be applied twice per month at weak strength.

Potting is best done in the spring, immediately after flowering, but can be done any time if the roots are kept as intact as possible, especially if plants are grown indoors. Phalaenopsis plants must be potted in a porous mix.  Repotting is usually done every 1 to 3 years.  

• Seedlings usually grow fast enough to need repotting yearly and should be repotted in a fine-grade medium.
• Mature plants are potted in a medium-grade bark mix and can grow in the same container until the potting medium starts to decompose, usually about 2 years. Root rot occurs if plants are left in a soggy medium.
• Indoors, phalaenopsis do best when potted in a fine bark mix, regardless of size, and in a net/mesh pot that is slipped into a larger plastic (ideally clear plastic) or ceramic pot.  The idea is that they can sit in about .5in (1.3cm) of water, which wicks up into the media but allows the roots to breathe.

It is also ideal, when repotting most phalaenopsis, to pot them leaning forward at about 45 degrees or more.  This will prevent the roots from “searching upwards”.  To repot, trim soft, rotted roots and spread the remaining roots over a handful of medium in the bottom of a new pot.  Fill the rest of the pot with medium, working it among the roots so that the junction of the roots and the stem is at the top of the medium.

• Phalaenopsis, The Genus

Further information can be found on the Phalaenopsis genus page.

Best orchid care practices are also provided for watering, repotting, and fertilizer types. There are also detailed discussions of growing orchids indoors, outdoors, or in greenhouses.

For more information on genus name changes, see Taxonomy.