Updated: Feb 5, 2022
The Phalaenopsis or 'Moth Orchid' is the most common orchid due to its ease of production and the availability of blooming plants year-round. Phals are easily grown in the home and stay in bloom for a very long time. A mature phal will be in bloom much of the year with graceful inflorescences loaded with good-sized blooms. From pure whites to unusual spotted harlequins, Phalaenopsis are sure to please. Unlike many other orchids, Phalaenopsis can be repotted anytime, though it is usually best to do so when not in bloom.
The culture of Phalaenopsis orchids involves windowsill light and consistent moisture. Phals do very well as houseplants and will grow and flower in a moderately bright windowsill. Each year a Phalaenopsis will grow two or three new leaves. Once the growth phase is complete, usually in the fall, a bloom spike will emerge from the stem beneath the second or third leaf from the top. Sometimes we have to help a Phalaenopsis that is grown in a consistently warm home to realize it is fall by allowing it to experience lower temperatures (60's) for several nights in order to set a bloom spike. Phalaenopsis orchids bloom in the late winter through the spring.
Culture for Doritis, a related genus, thought by some to be conspecific with Phalaenopsis, and Doritaenopsis, a hybrid between the two genera, is the same as for pure Phalaenopsis.
Phalaenopsis are ‘low’ light orchids. In nature, they grow attached to the trunks of large trees, below the leaf canopy, so they are familiar with bright, but indirect light, that passes through the canopy. They grow easily in a bright window, with little or no sun. An east window is ideal in the home; shaded south or west windows are acceptable. A Phal’s leaves should be olive green. If they are darker it means the plant is not getting enough light; red tinged leaves mean the plant is getting too much light.
Once the plant is in bloom you can place it anywhere in your home out of direct sunlight. If in a greenhouse, 70 to 85 percent shad must be given. Think of a greenhouse that has lots of natural light but the glass is whitewashed to diffuse the direct rays of the sun, that’s the exposure they love. No shadow should be seen if you hold your hand one foot above a plant's leaves.
You can also achieve good phalaenopsis orchid care in indoor spaces away from windows, as long as there is a good source of light, either natural or artificial, to ensure that the plant gets sufficient light. Artificial lighting can easily be provided. Four fluorescent tubes in one fixture supplemented by incandescent bulbs are placed 6 to 12 inches above the leaves, 12 to 16 hours a day, following natural day length.
Phalaenopsis Orchids are ideally suited to indoor temperatures. Temperatures for Phalaenopsis should usually be above 16°C at night, and range between 21°C and 27°C 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 28 and 32°C. Night temperatures to 12°C 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. Be sure to keep them away from air conditioners and heaters as well as any hot or cold drafts.
"The Higher the Temperature, the Greater the Plant's need for Humidity"
Water is especially critical for phalaenopsis. Because they have no major water-storage organs other than their leaves, they must never completely dry out. How often you water will depend on the potting medium. Bark retains less water than moss. If your phal is potted in bark watering once in 2 days is generally sufficient. If your plant is potted in moss, water when the top feels dry. Generally Phalaenopsis require watering about once every 2 to 4 days under outdoor conditions. The amount of light and heat your plant receives will also affect how soon your phal needs watering. Summer months will need more frequent watering, winter will need less. After a few watering, you will be able to tell by the weight of the pot whether or not it is time to water again. If in doubt, wait a day.
Water your Phalaenopsis orchids early in the morning. This insures complete water evaporation on the foliage as well as the crown by nightfall. Water with rain, distilled, or reverse-osmosis water as the mix approaches dryness. Never use water that has been softened by a water softener.
"Don’t Water The Leaves And Flowers Of Your Orchids"
You should only water the roots of your orchid, as getting the leaves and flowers of your orchids wet can lead to all kinds of problems. If you pour water onto your orchid from above, you are likely to leave standing water in the crown where the new leaves are growing. If you do this repeatedly, this standing water will encourage crown rot to form which can very quickly damage your plant or even result in it dying.
"Don’t Mist Your Phalaenopsis Orchids"
Many people advise spraying your orchids with a mist of water to increase the humidity levels in the air in the direct vicinity of the orchid. This is generally not a good idea, as it is an inefficient way of increasing local humidity levels, and water will gather on the leaves and flowers. This can lead to mold spots developing on the leaves, or more commonly on the petals of the flowers.
After you have watered your orchid, it is really important to make sure that the plant is well drained before placing it back on display, and to ensure that the roots are not left standing in water for long. The roots won’t tolerate this and can result in root rot if you do.
The Ice Cubes Controversy
There is a lot of conflicting advice about whether regular use of 3 ice cubes to water your orchids is it good thing to do or not. It is often highlighted as a good idea, as it encourages people not over water their orchids due to the small amount of water in ice cubes. For people growing orchids in colder conditions, towards the bottom of the ideal temperature range, using ice to water your orchids may increase cold temperature stress for your plants.
In warmer climates, watering your orchids with ice is not going to have a significantly adverse impact. The ice will melt quickly and will not significantly impact the temperature of the roots or plant. However, in warmer climates, it is likely that your orchids will need more water, and using ice cubes may not provide sufficient hydration for your plants.
Phalaenopsis orchids are of a monopodial growth without any pseudobulbs to help store moisture. For this reason, the recommended humidity being between 50 and 80 percent.
Using a Humidity Tray is one of the best ways. These trays are nothing more than a water-holding tray filled with gravel. The gravel-filled trays are filled with water to a level just below the surface. To prevent plants sitting on constantly wet gravel the plants are placed on small saucers or pieces of plastic or metal grid placed on top of the trays. A plumpy and wrinkleless leaves indicates a well-hydrated plant.
In humid climates, as in greenhouses, it is imperative that the humid air is moving. Leaves should be dry as soon as possible, always by nightfall.
"Don’t Leave The Roots Of Your Phalaenopsis Orchid Standing In Water"
Phalaenopsis are one of the longest blooming orchid genera, producing flowers that last from 2 to 6 months before dropping. Phalaenopsis have also been known to bloom 2 to 3 times per year once they have reached a mature size. After it has flowered the spike turns brown, cut it off near the base of the plant where it emerged.
Pruning for Re-Bloom
Phalaenopsis orchids rebloom on old spikes with a new stalk emerging from a triangular node along the stalk. To trigger re-blooming, your orchid will need a little more attention than what you usually give it. The thrill when your orchid blooms for a second time, however, makes the small investment in time and effort required to trigger orchid reblooming well worth the effort.
Phalaenopsis orchids expend a lot of energy to create the large, beautiful flowers for which they are prized. Under normal circumstances, your orchid will enter a resting period called dormancy once it has finished blooming. Dormancy allows the plant time to rest and replace the nutrients expended during blooming. Nutrients and water are stored in the plant’s leaves until they are needed for growth and blooming. Dormancy typically lasts from 6 to 9 months and your orchid may re-bloom on its own. But sometimes orchids need a little help activating the natural rhythm that leads to blooming.
Steps to Trigger Re-blooming:
Good light conditions are essential to give an orchid sufficient energy to stimulate re-blooming. Put your orchid in a bright window, ideally south or east facing, with plenty of indirect sunlight.
To stimulate re-flowering, your Phalaenopsis orchid should ideally experience a variation in the temperature between day and night. A daytime temperature of between 21-29 °C and a nighttime low of 16-21 °C is ideal.
Trying to cut nodes in positions as mentioned above. The site of the cut often becomes the point at which a new stem or stems will grow.
Increasing the humidity of the local environment, producing a climate which is more favorable for the orchid to thrive and re-flower in. Try Humidity Trays.
The vegetative phase after flowering is the time when fertilizing is the most important. I like to ensure that I fertilize my orchids approximately every 2 weeks with a reduced strength fertilizer solution throughout this growth phase.
Cutting Spikes on a Phalaenopsis
For most orchid genera the flower spike should be cut back after the bloom. This is usually indicated by the plant as the spike turns brown. For Phalaenopsis it can be a bit tricky to know what to do and to make matters more confusing there are differing schools of thought on the issue.
On most Phalaenopsis the bloom spike will turn brown after the plant is finished bearing flowers on a spike. It may not turn brown all the way down, however. One school of thought says to cut the spike above a node on the stem and allow the plant to rebloom again as a branch off the existing spike. The other school of thought says to always cut the flower spike off at the base when the blooms drop. Blooms take energy from the plant so cutting the spike entirely off allows the plant to gather its energy for an even more spectacular bloom in the future. Allowing the spike to branch results in more blooms sooner but takes energy from the plant resulting in often smaller blooms.
It seems in orchid culture there are exceptions to every rule. Some Phalaenopsis should not have their bloom spikes cut. These Phals have in their parentage species such as violacia, amboninsis, cornu-cervi, etc. These Phals usually bear only a few blooms at the end of a spike and will bear blooms sequentially on the same spike for a very long time, seemingly forever. The primary reason to cut these spikes is if the plant becomes too unruly.