Phalaenopsis Culture Sheet
How to grow Phalaenopsis orchids.
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Phalaenopsis orchids require lower light to grow and flower than other orchids. Low light for a plant may appear brighter than how we light our homes. A hand held one foot above the foliage should cast a shadow with blurred edges, but if you can’t see a shadow, the light is too low. Healthy, vigorous plants which refuse to bloom may not be receiving enough light. The leaves should be medium to light green in sufficient light, and not dark green. Avoid direct sun.
Window: Place phalaenopsis in a bright east, or west facing window. The morning sun of an east exposure is ideal. A south window can be used, but watch for signs of developing sunburn. This will appear initially as a yellowing or tan patch facing the source of light. A sheer curtain can be used to protect from sun damage.
Artificial light: High-pressure sodium lights, fluorescent and compact fluorescent lights, and LED lights can all be used to grow phalaenopsis orchids. Place phalaenopsis orchids closer to the ends of the growing bench if necessary, and move plants with higher light requirements closer to the middle.
Outdoors: Like most orchids, phalaenopsis benefit from being moved outdoors after nighttime temperatures remain above 60 degrees. Plants may need to be acclimated gradually to brighter conditions, and should be kept out of hot sun.
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Phalaenopsis orchids grow well at the temperatures most of us keep our homes. The conventional wisdom on blooming phalaenopsis orchids is that they are stimulated into blooming by dips to about 55 °F at night, with days 15 – 20 °F warmer, until the initiation of a flower spike. New research by Dr. Yin-Tung Wang suggests that only an overall 10 – 15 °F dip from the average growing temperature is needed. This can be achieved by placing the plant on the sill of a drafty window in winter. A combination of bright light and excessive heat may result in sunburn, which will appear initially as a patch of yellow, tan, or white discoloration, fading to light tan and forming a dry patch. Check plants regularly for sunburn.
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Phalaenopsis orchids want to be watered very heavily on watering day, and then approach dryness before being watered again. Phalaenopsis roots will rot if kept wet for too long, or suffocated by wet media. To water at a sink, run a tap of room temperature water, and hold the pot in the water, moving it so that the entire pot is thoroughly flushed with water to thoroughly drench the medium. Allow the pot to drain, and place back into the growing area. This is an ideal time to check for sun damage, pests, and other developing problems.
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Formula: Phalaenopsis orchids benefit from a higher nitrogen fertilizer formula such as 30-10-10, but can also be given a balanced fertilizer. The formula of fertilizer required will change depending on the amount of dissolved minerals in your local tap water. Water with high total dissolved solids (TDS) will require fertilizer without these additional minerals, or it may burn the roots. Water with low dissolved magnesium and calcium will require a formula that supplements these essential minerals. The Chicago municipal water supply is very good for growing orchids.
Schedule: Most orchid growers follow a “weakly-weekly” fertilization schedule, and will use ¼ of the package recommended strength, every time they water. Some growers will decrease or discontinue fertilization from late fall to early spring, or when the plant is not actively growing, while other growers may feed evenly year-round. Some growers report success switching to a “bloom booster” formulation in the months leading up to that orchid’s blooming season. Flush the pot with plain water without fertilizer once every month to avoid the buildup of fertilizer salts.
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Phalaenopsis orchids do not require a dry dormancy or rest period, although their water needs will change with the amount of light provided as seasons change.
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Use a coarse, free draining potting medium like fir bark or a fir bark mix. Some growers have success using lightweight expanded clay aggregate (LECA) or Hydroton in a container that keeps a small reservoir of water, in a method called semi- hydroponic.
Care requirements created with information from the American Orchid Society, and Illinois Orchid Society growers.
