The Phalaenopsis orchid, commonly known as the Moth Orchid, is admired for its long-lasting blooms. Once these flowers fade, inducing a new flowering cycle requires more than routine houseplant care. Re-blooming an orchid demands specific manipulation of its environment and nutritional inputs to signal the plant that it is time to produce a new flower spike. This process involves replicating the distinct seasonal changes the plant experiences in its natural habitat.
Preparing the Plant After Flowering
The first step after the last flower drops is to address the spent flower spike, which is the long stem that held the blooms. The decision on where to cut the spike depends on your goal and the overall health of the plant. Using a sterile tool, like a razor blade or sharp scissors, prevents the introduction of pathogens into the fresh cut.
If the spike is still green and healthy, you have the option to cut it just above the second node, which is a small, triangular bump located along the stem. This technique encourages the plant to produce a secondary, smaller flower spike from that node, often resulting in blooms within a few months. However, this secondary flowering can sometimes tax a weaker plant, leading to smaller flowers.
For small, newly acquired, or less vigorous plants, cut the spike down as close to the base as possible. This directs the plant’s energy toward strengthening its leaves and roots for a more robust flowering cycle in the following season. If the entire spike begins to turn yellow or brown, it should be removed completely at the base, as it is no longer capable of producing new blooms.
While the plant is resting, inspect the root system and potting medium. Healthy roots should appear firm and plump, typically green when wet and silvery-gray when dry. Mushy or brown roots should be carefully pruned away with sterilized shears.
If the growing medium, usually fir bark or sphagnum moss, has broken down into a fine, dense material, repotting is necessary. Degraded media holds too much moisture, suffocating the roots and preventing the plant from gathering the energy needed for a new flower spike. Repotting into fresh, airy medium ensures good drainage and air circulation.
Manipulating Light and Temperature Triggers
Once the plant is physically prepared, the next phase involves simulating the environmental cues that signal the onset of the blooming season. Light is one of the most significant factors in this process, as the plant needs sufficient energy to support the growth of a new flower spike. Phalaenopsis orchids require bright, indirect light to initiate blooming, which is often found in an east- or west-facing window.
Inadequate light is a common reason a healthy orchid fails to re-bloom. Deep, dark green leaves indicate insufficient light, while a healthy, light-green color suggests the plant is receiving enough energy. Ensure the plant never receives harsh, direct afternoon sun, which can quickly scorch the leaves.
The most specific and reliable trigger for flower spike initiation in Phalaenopsis orchids is a consistent drop in night temperature. This temperature differential, often referred to as “the chill,” mimics the natural change in seasons. The plant needs a sustained period of cooler night temperatures, ideally in the range of 55°F to 65°F.
This cool period must be maintained for approximately two to four weeks, with a daytime temperature 10°F to 15°F warmer than the nighttime low. This sustained difference signals the plant to shift its energy from vegetative growth to reproductive growth, initiating a flower spike. Moving the plant near a drafty window during cooler months can achieve this necessary temperature drop.
Adjusting Nutrient and Watering Schedules
As the plant enters the phase where it is being encouraged to bloom, a specific adjustment to the fertilizer regimen is necessary to support the energy demands of flowering. During the vegetative growth phase, a fertilizer higher in nitrogen is typically used to promote leaf and root development. However, to initiate blooming, the focus shifts to phosphorus and potassium.
Switching to a “bloom booster” fertilizer with a higher middle and third number in the NPK ratio, such as 10-30-20, encourages flower production. Phosphorus is involved in energy transfer and flower development, while potassium supports overall plant health. Apply this fertilizer at one-quarter to one-half the recommended rate to prevent the build-up of salts that can damage the delicate orchid roots.
During the spike induction phase, the frequency of fertilization should remain consistent, typically once every one to two weeks, as part of the regular watering cycle. Every fourth watering should be a flush with plain water to rinse away any accumulated mineral salts from the potting medium. This flushing helps prevent root burn and toxicity.
Watering frequency requires slight modification during the cool-temperature period to enhance the environmental stress signal. A slight reduction in water volume or frequency can contribute to the stress that encourages blooming. Always ensure the potting medium is allowed to dry slightly between waterings, as overly saturated roots can lead to rot.