Phalaenopsis (fal-en-nop-siss) Culture

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Phalaenopsis, commonly known as the moth orchid, are epiphytes (tree dwelling plants) native to Southeast Asia, Philippines and Australia. They are the most popular of all orchids for growing in the average home and have a blooming longevity of 2 to 4 months! Mature plants can flower two times a year simply by cutting the stem off at a point one inch above the upper most node. In essence, you are cutting off only the flowering segment of the stem and leaving the lower portion remaining. This “cropping back” of the stem will encourage a new bloom shoot to emerge from one or two of the nodes just below the cut.

After the completion of this second flowering cycle, then cut the entire stem off at the point where it emerged from the plant. A new flowering stem will then emerge from the plant which will produce the flowers for the next season.

LIGHT
In our Wisconsin climate Phalaenopsis prefer to be grown in a bright area where they will receive some direct sun. The best exposure is a bright east window where the plant will receive direct sun on the leaves during most of the morning hours. A western exposure is also suitable, but be sure the plant receives no more than two hours of direct sun daily.

Some tips for growing in a south exposure: During the winter months the south exposure in our Wisconsin latitude can be very bright due to the sun being so low in the horizon. During this period the direct sun in a south window can damage the leaves of a Phalaenopsis, therefore it is recommended to position the plant where it will receive no more than two hours of direct south sun daily. During the summer months the south exposure has the opposite effect where the angle of the sun is very high and no direct light is received. It is then that you will need to move the plant to an east or west exposure to ensure proper light levels or move the plant to a shaded outdoor location or supplement light with an artificial plant light. Whichever exposure or light source you choose for growing your Phalaenopsis, try to provide as much light as possible throughout the year without causing sun burn on the leaves. This will ensure the absolute best growth and subsequently the best flowering.

Phalaenopsis can also be grown and flowered successfully under artificial plant lights such as fluorescent lights, high pressure sodium or metal halide. Some artificial plant lights produce enough heat to burn the leaves if positioned too close to the plant. When using any artificial plant light source be sure to position the plants under the lights in accordance to the needs of the plants. If in question, consult Orchids Garden Centre & Nursery for more detailed information.

TEMPERATURE
One of the cultural elements that make the Phalaenopsis such a popular plant is that they love to grow in the same temperatures that we also live with in our homes. On average these plants grow best between 62 degrees at night to 80 degrees day. Of course we do not heat our homes to 80 degrees during the winter day so do not read this as they absolutely require that much daytime warmth however, the warmer the daytime temperature, the faster the plant will produce new leaves and subsequently more flowering spikes.

To encourage these plants to produce their flower spike it is recommended to expose them to cool nighttime temperatures of 58 to 60 degrees for a period of 4 to 6 weeks during the fall or early winter. Typically the natural cooling of our climate from the summer heat is enough to stimulate a new bloom spike however, in some cases the plant will need an extra boost by artificially providing the cooler climate. This can best be achieved by placing your plant in a room that you can reduce the nighttime heat source significantly, such as a downstairs room, a spare bedroom where the heat source can be reduced or even a semi heated garage area. Remember that the plant still requires daytime light but does not necessarily need it as bright as it did during the growing months. If you do not see a new bloom spike growing out of your plant by January, then you need to continue this cool treatment for just a few more weeks.

WATER
There are many factors that dictate how often your individual plant will need watering however, there is one main rule to always follow. Phalaenopsis like to dry out at the roots between watering. Since these plants are growing on trees in their native environment they are accustomed to being dry at the roots between each watering cycle. The root of a Phalaenopsis is covered with a fleshy water retentive material called velamen. The white, silvery velamen around the root absorbs and holds water like a sponge which then the plant relies on during the next week or more.

If your Phalaenopsis is growing in a bark type mix it is important to allow that mix to become dry beneath the surface before watering again. This can be somewhat difficult to diagnose by looking at the mix, therefore it is recommended to probe into the mix with either your finger or another object such as a sharpened pencil. Another popular method of moisture diagnosis is to get familiar with the weight of the pot. When the bark mix is thoroughly dry the pot becomes very lightweight. In most cases watering every 7-10 days is standard.

To water your Phalaenopsis properly it is best to water the pot thoroughly until water runs freely from the pot. Usually this is done at the sink or somewhere you can do a good flushing of the pot. Always remove your pot from any decorative container to allow for proper drainage. Never allow your pot to stand in any water as this will cause root rot. Never use softened water on any of your orchids.

If your Phalaenopsis is growing in sphagnum moss the watering frequency will be much less. Generally the moss has a tendency to retain much more water than a bark based mix. Allow the surface of the moss to become dry to the touch between watering. In most cases watering the moss every 10-14 days is standard.

FERTILIZER
Phalaenopsis are fairly active growing plants and therefore fertilizer is essential for good growth and flowering. We recommend applying a 20-20-20 or similar balanced type fertilizer once every 2 to 3 weeks throughout the entire year. A safe dilution ratio is one level teaspoon of fertilizer mixed in one gallon of water. Do not over-fertilize as this will cause permanent root damage.

HUMIDITY
Like many orchids, Phalaenopsis enjoy a moderately humid climate of 50% or greater. When growing these plants indoors it is recommended to increase humidity around the plant. This is simply achieved by placing your plants on a humidity tray, misting them adequately in the morning, or grouping your plants all together in one area.

REPOTTING
We recommend repotting Phalaenopsis every year, to every year and a half. If you are not experienced or comfortable doing this yourself we offer the repotting service at our greenhouse for a small fee. Your recently purchased Phalaenopsis may be ready for a repotting job as soon as it has finished flowering. Inquire with us as to when your individual plant was last repotted. Good indicators for a repot candidate are: when the bark has become broken down, rotted or retains moisture for an extended period; when roots are becoming abundant at the surface or outside of the pot; or when the pot is completely root bound. It is best to repot during the months of March through October provided the plant is not in a blooming state at that time. It is acceptable to repot a Phalaenopsis during flower spike development as long as the buds are not yet visible.

To properly repot your Phalaenopsis simply remove the plant from its pot and let all of the existing potting mix fall away from the roots. Once you have all the mix away from the roots you will be able to distinguish the good healthy roots from the not-so-healthy, rotted roots. The healthy roots are firm and usually white, green or silver in color. The rotted or unhealthy roots are soft, brown and generally mushy. Remove the unhealthy roots using a scissors or pruning tool. In many cases there are no unhealthy roots to prune away so you would then simply move on to the next step.

A note about orchid viruses: most commonly the transmission of orchid viruses is caused by using the same cutting tool on multiple plants. The most effective method to reduce virus transmission from plant to plant is to briefly flame sterilize all your cutting tools between use on each plant. A simple Butane torch or a gas stove are handy items for this purpose. This practice should be implemented when repotting as well as when cutting off expired flowering stems.

Once you have cleaned up the root mass you are ready for the potting process. Selecting the proper size pot is the next most important aspect in properly repotting a Phalaenopsis. Select a pot that is only large enough to accommodate the roots comfortably. If you need to force the root mass into the pot then it is not quite large enough and you may need one size larger. The rule of thumb is not to use any pot larger than what comfortably accommodates the roots. It is always recommended to use a new pot and be sure it has adequate drain holes in the bottom and/or side.

Set the roots into the pot and begin adding our moistened fir bark orchid potting mix. Work the mix in between the roots by gently shaking or tamping the pot to allow the mix to fill in between the root crevasses. Position the plant so the junction of the roots to the plant is at the surface of the mix. It is important not to bury the plant too deep.

Once the pot is nearly full of the mix, begin to pack the mix somewhat firmly to properly anchor the plant into the pot. Sometimes a blunt tool is needed to properly firm up the mix. Repotting is now completed. Wait one week and then water the plant thoroughly.

For more assistance with your Phalaenopsis or any other Orchid, please call us at 608-831-4700, send an email, or visit our store.

Happy growing, from Orchids Garden Centre & Nursery!