General information
Phalaenopsis, or the "Moth Orchid," is the most common orchid due to its ease of cultivation and the availability of year-round flowering plants. Phalaenopsis orchids are easy to grow indoors and remain in bloom for a long time. A mature Phalaenopsis will bloom for much of the year with graceful inflorescences laden with good-sized flowers. From pure whites to unusual spotted harlequins, Phalaenopsis orchids are certainly popular. Unlike many other orchids, Phalaenopsis orchids can be repotted at any time, although it's usually best to do so when they're not in bloom.
Growing Phalaenopsis orchids requires light on the windowsill and constant humidity.
Phalaenopsis are very well suited as houseplants and grow and flower in a moderately bright windowsill.
Each year, a Phalaenopsis develops two or three new leaves.
Once the growth phase is complete, usually in autumn, a flowering stem will emerge from under the second or third leaf from the top.
Sometimes we need to help a Phalaenopsis grown in a constantly warm house to understand that it is autumn by leaving it exposed to lower temperatures (15 °C) for several nights, so that the flowering stem can emerge.
Phalaenopsis orchids bloom from late winter until 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.
Light requirements
Phalaenopsis are orchids that prefer low light. In nature, they grow attached to the trunks of large trees, beneath the canopy, so they're familiar with bright, but indirect, light coming through the canopy. They thrive best in a bright window with little or no sun. An east-facing window is ideal indoors; shaded south- or west-facing windows are acceptable. Phalaenopsis leaves should be olive green. If they're darker, it means the plant isn't getting enough light; reddish leaves mean the plant isn't getting enough light.
Once the plant is in bloom, you can place it anywhere in the house, away from direct sunlight. If it's in a greenhouse, provide 70 to 85% shade. Consider a greenhouse with plenty of natural light, but with whitewashed glass to diffuse direct sunlight: this is the exposure they prefer. You shouldn't see any shadows if you hold your hand within a foot of the plant's leaves.
Phalaenopsis orchids can be well cared for indoors, away from windows, as long as there is a good light source, whether natural or artificial, to ensure the plant receives sufficient light. Artificial lighting is easily provided. Four fluorescent tubes in a single fixture, supplemented by incandescent bulbs, are positioned 15-30 cm above the leaves, for 12-16 hours a day, following the natural day length.
Temperature requirements
Phalaenopsis orchids thrive in indoor temperatures. Temperatures for Phalaenopsis orchids should generally be above 60°F (16°C) at night and range between 70°F (21°C) and 80°F (27°C) or higher during the day. While higher temperatures promote faster vegetative growth, higher temperatures must be accompanied by increased humidity and air movement, with maximum temperatures recommended between 82°F (28°C) and 90°F (32°C). Nighttime temperatures as low as 54°F (12°C) are desirable for several weeks in the fall for flowering. Fluctuating temperatures can cause bud drop in plants ready to bloom. Be sure to keep them away from air conditioners and heaters, as well as hot or cold drafts.
Water requirements
Water is especially important for phalaenopsis. Since they don't have any significant water storage organs other than their leaves, they should never dry out completely. The frequency of watering will depend on the soil. Bark retains less water than moss. If your phalaenopsis is potted with bark, watering it once every 7 days is generally sufficient. If your plant is potted with moss, water it when the top part feels dry. Generally, phalaenopsis require watering about once every 2-4 days outdoors. The amount of light and heat your plant receives will also influence watering frequency. In the summer months, more frequent watering will be needed, while in the winter, less. After a few waterings, you'll be able to tell by the weight of the pot whether it's time to water again. If in doubt, wait a day.
Water your Phalaenopsis orchids early in the morning. This ensures complete evaporation of water from the leaves and crown by sunset. Water with rainwater, distilled water, or reverse osmosis water when the mixture begins to dry out. Never use softened water.
“Don't water the leaves and flowers of your orchids”
You should only water the roots of your orchid, as wetting the leaves and flowers can cause several problems. If you pour water onto your orchid from above, you'll likely leave standing water in the crown, where the new leaves are growing. If you do this repeatedly, standing water will promote root rot, which can quickly damage the plant or even cause its death.
“Don't spray your Phalaenopsis orchids”
Many recommend spraying orchids with a little water to increase the humidity in the immediate area. However, this is generally not a good idea, as it's not an effective method of increasing local humidity, and the water accumulates on the leaves and flowers. This can lead to mold spots on the leaves or, more commonly, on the flower petals.
After watering the orchid, it's essential to ensure the water drains well before putting it back on display, and to avoid allowing the roots to remain in water for too long. The roots won't tolerate this and could rot.
The Ice Cube Controversy
There are many conflicting opinions about whether or not to regularly use three ice cubes to water orchids. It's often cited as a good idea, as it encourages people to avoid overwatering their orchids due to the small amount of water they hold. For those growing orchids in colder conditions, lower than the ideal temperature range, using ice to water orchids can increase cold stress for the plants.
In warmer climates, watering orchids with ice won't have a significant negative impact. The ice will melt quickly and won't significantly affect the temperature of the roots or the plant. However, in warmer climates, orchids will likely require more water, and using ice cubes may not provide sufficient hydration.
WE STRONGLY DISCOURAGE THIS TECHNIQUE
Humidity requirements
Phalaenopsis orchids are monopodial, lacking pseudobulbs that help store moisture. Therefore, the recommended humidity is between 50 and 80%.
Using a humidifier tray is one of the best methods. These trays are simply a water container filled with gravel. The gravel-filled trays are filled with water to just below the surface. To prevent the plants from sitting on the constantly wet gravel, they are placed on small saucers or pieces of plastic or metal mesh placed over the trays. Fleshy, wrinkle-free leaves indicate a well-hydrated plant.
In humid climates, such as greenhouses, it's essential to keep humid air moving. Leaves should be dry as soon as possible, always by sunset.
“Don't leave the roots of your Phalaenopsis orchid submerged in water”
Flowering
Phalaenopsis is one of the longest-blooming orchid genera, with flowers that last from 2 to 6 months before falling. Phalaenopsis is known to flower two or three times a year once it reaches maturity. After flowering, the stem turns brown; cut it near the base of the plant, where it emerged.
Pruning for reflowering
Phalaenopsis orchids rebloom on old stems with a new stem emerging from a triangular node along the stem. To trigger reblooming, your orchid will require a little more attention than usual. The thrill of seeing your orchid bloom for the second time, however, more than makes up for the small investment of time and effort required to trigger reblooming.
Phalaenopsis orchids expend a lot of energy to create the large, beautiful flowers they're known for. Under normal circumstances, your orchid enters a period of rest called dormancy once flowering is complete. Dormancy allows the plant to rest and replenish the nutrients consumed during flowering. Nutrients and water are stored in the plant's leaves until they're needed for growth and flowering. Dormancy typically lasts 6 to 9 months, and your orchid may rebloom on its own. But sometimes orchids need a little help to activate the natural rhythm that leads to flowering.
Steps to trigger reblooming:
- Good lighting is essential to provide the orchid with enough energy to stimulate reblooming. Place your orchid in a bright window, ideally facing south or east, with plenty of indirect sunlight.
- To stimulate reblooming, your Phalaenopsis orchid should ideally experience a temperature difference between day and night. A daytime temperature of 21-29°C (70-85°F) and a nighttime low of 16-21°C (61-70°F) are ideal.
- By increasing the humidity in the local environment, you create a more favorable climate for orchid growth and reblooming. Try humidifiers.
- The vegetative phase after flowering is the time when fertilization is most important. I like to make sure to fertilize my orchids about every two weeks with a low-strength fertilizer solution during this growth phase.
Cutting the spikes on a Phalaenopsis
For most orchid species, the flower stem should be pruned after flowering. This is usually indicated by the plant itself, as the stem turns brown. For Phalaenopsis, it can be a bit tricky to know what to do, and to further complicate matters, there are different schools of thought on the subject.
In most Phalaenopsis, the flowering stem will turn brown after the plant finishes blooming. However, it may not turn brown all the way through. One school of thought recommends cutting the stem above a stem node and allowing the plant to rebloom as a branch from the existing stem. Another school of thought recommends always cutting the flowering stem at the base when the flowers fall. Flowers drain the plant's energy, so cutting the stem completely allows the plant to gather its energy for even more spectacular blooms in the future. Letting the stem branch out results in more blooms sooner, but it also drains the plant of energy, often resulting in smaller blooms.
There seem to be exceptions to every rule in orchid cultivation. Some Phalaenopsis orchids shouldn't have their flower spikes cut. These Phalaenopsis orchids include related species such as Violacea, Amboinensis, Cornu-Cervi, and others. These Phalaenopsis orchids typically bear only a few flowers at the end of a stem and will produce sequential blooms on the same stem for a long time, seemingly forever. The main reason to cut these spikes is if the plant becomes too unruly.
Each Phalaenopsis spike will have at least a few nodes covering it before flowering. Each of these nodes has the potential to branch during or after the initial flowering.
Fertilizer requirements
A healthy Phalaenopsis will benefit greatly from the addition of fertilizer, but it won't solve most problems for a sick orchid. Always use a low-strength fertilizer, but use it more frequently, rather than using the highest concentration less often. This is mainly due to the nature of the growing medium. Phalaenopsis orchids are often grown in bark or a combination of bark, sphagnum moss, perlite, etc. These don't retain moisture and nutrients like soil, so regular application of immediately bioavailable nutrients will be more beneficial for your orchids.
Phalaenopsis orchids generally don't require much fertilizer, if any, during the flowering stage. Fertilizer is truly necessary during the vegetative stage, to give the plant the energy it needs to begin developing new stems, buds, and flowers.
Recommended fertilizers:
- Balanced fertilizer for growth: 20-20-20 (NPK) – 2 grams per liter of water – Spray once every two weeks (14 days)
- High phosphorus fertilizer for flowering: 0-52-34 (MPK) – 1 gram per liter of water – Spray every two weeks (14 days) – Use only in the vegetative stage
Repotting, substrates and propagation
There are two main reasons why a phalaenopsis orchid might need to be repotted. The first is when the growing medium begins to deteriorate and decompose. The second is when the roots outgrow the pot the orchid is growing in. Repotting is usually done every one to three years. Mature plants can grow in the same container until the growing medium begins to decompose, usually after two years.
“Root rot occurs if plants are left in soggy soil.”
Orchids generally prefer to be contained by their roots, so don't use a pot larger than necessary. It's advisable to choose a transparent pot for Phalaenopsis orchids. Orchid roots contribute to photosynthesis and energy production, so ensuring they have access to light contributes to the plant's overall health and vigor. Since the roots absorb a lot of moisture and nutrients directly from the air, having plenty of ventilation and drainage holes will allow good air circulation to your orchid's roots.
The most common growing medium is a tree bark-based mix, although any fast-draining medium can be a good alternative. Phalaenopsis are successfully grown in perlite, expanded clay, peat moss, bark, sphagnum moss, and various mixed substrates. As long as we adapt to the characteristics of the chosen growing medium, we can achieve good results.
The brown ones are unhealthy or dead roots.
It's a good idea to assess the roots when repotting. Any roots that appear damaged or diseased can be removed by hand or with a pair of sharp, clean garden shears. Don't worry too much about removing diseased roots. The plant will thrive much better with a small volume of healthy roots than with a large volume of roots with a diseased or unhealthy section.
Phalaenopsis plants, being monopodial, cannot be divided. They will naturally produce "baby" orchids, known as keiki. These are identical copies of the mother plant and usually appear on an old or new flower spike. After about a year, the keiki can be removed from the mother plant and placed in a separate pot. The keiki is ready when it has two or three leaves and its own roots about 8 cm long.
Pests and other problems related to Phalaenopsis
Fungal and bacterial diseases of Phalaenopsis are common due to the high humidity levels they require to survive. Fungal agents cause problems such as root rot, leaf spots, leaf discoloration, and flower spots.
