The Phalaenopsis, or Moth Orchid, is the variety most commonly kept in homes, and its popularity is due to the long-lasting, beautiful blooms it produces. After the initial display of flowers fades, the primary goal for many orchid owners is to trigger a second blooming, which requires the plant to grow a new flower spike. Unlike many houseplants, this reblooming process is not automatic and depends on specific environmental cues to shift the plant from a purely vegetative state to a reproductive one.
Preparing the Plant: Post-Bloom Pruning
After the last flower drops, address the old spike to redirect the plant’s energy. Sterilize your pruning tool (razor blade or shears) with 70% isopropyl alcohol before making any cut to prevent the transmission of pathogens. The decision on where to cut the spent spike depends on your goal for the next bloom.
To encourage a quick secondary bloom, cut the spike back to a viable node. Locate the second or third node from the base of the plant and make a clean cut about half an inch above it. A new, smaller flower spike may emerge from this node within two to three months, although the resulting flowers are typically fewer in number and smaller than the original bloom.
Alternatively, cut the entire flower spike off near the base, leaving only about an inch of the stem. This method allows the orchid to conserve all its energy for root and leaf growth, leading to a stronger, healthier plant. A well-rested orchid that has stored sufficient energy is more likely to produce a robust new spike in the next blooming cycle, resulting in a larger and more impressive display of flowers.
Establishing Ideal Conditions for Health
A robust plant is a prerequisite for reblooming, as producing a flower spike requires a significant reserve of stored energy. Phalaenopsis orchids require bright, indirect light, with an east or west-facing window often providing the ideal conditions. If the light is sufficient, the leaves should be a healthy, light green color; dark green leaves suggest the light is too low for optimal energy production.
Proper watering requires allowing the potting medium to become slightly dry between applications, as these plants do not tolerate standing water around their roots. Water thoroughly until liquid drains from the bottom holes, ensuring the roots are saturated, then wait until the medium is almost dry before watering again. Since Phalaenopsis are epiphytes (growing on trees in nature), they thrive with high ambient moisture, making humidity levels between 50% and 70% beneficial.
Fertilization should be consistent while the plant is actively growing and not in bloom, often following a “weakly, weekly” schedule. This involves applying a balanced orchid fertilizer diluted to one-quarter or one-eighth of the strength recommended on the label. This regular, light feeding ensures the orchid stores necessary nutrients without risking fertilizer burn while rebuilding energy reserves after the previous bloom.
Triggering the New Flower Spike
Once the plant is healthy and mature, the primary mechanism for triggering a new flower spike is a sustained drop in temperature. Phalaenopsis orchids interpret cooler temperatures as a signal to transition from vegetative to reproductive growth, mimicking their native habitat in autumn or early winter. The most effective method is to expose the orchid to a consistent temperature shift for several weeks.
Specifically, the orchid needs a drop in temperature, with nighttime temperatures consistently falling into the range of 55°F to 65°F. This cool period should maintain a difference of about 10–15 degrees Fahrenheit between the daytime and nighttime temperatures to mimic natural conditions. The daytime temperature should remain comfortable, ideally between 70°F and 80°F.
A sustained period of two to four weeks with these cooler nighttime temperatures is usually sufficient to initiate the formation of a flower spike. This temperature change can be achieved by moving the orchid near a slightly cracked window at night or to a cooler room, provided the temperature does not drop below 50°F, which can cause chilling injury. Slightly reducing watering frequency during this cooler period can also help signal the dormancy-like state that precedes spiking.
Spike Development and Care
After the temperature cue, a new flower spike will appear, often emerging from the side of the plant near the base. When the spike is about 5 to 6 inches long and still pliable, it is the appropriate time to begin staking it.
A support stake should be gently inserted into the potting medium, avoiding the dense root ball in the center of the pot. The spike should be loosely secured to the stake with soft ties or clips, allowing the plant to be trained into an aesthetically pleasing, upright position. As the spike continues to grow, it will naturally bend toward the strongest light source, a tendency that can be used to guide its final shape.
Once the spike is established, the orchid can be returned to its regular, slightly warmer growing area, since blooming does not require the sustained cool temperatures used for initiation. Fertilization can resume its normal schedule, as the plant needs nutrients to fuel the development of the spike and flower buds. Protecting the developing buds from cold drafts, hot air vents, or sudden environmental changes is important, as these can cause the buds to drop prematurely.