Phal CTL Ambo Tetralacea

Phalaenopsis are “low” light orchids (900-1500 footcandles). They grow beautifully in an east window and can be grown in a south or west window if protected by a sheer curtain. Artificial lighting can easily be provided. Usually artificial lights are placed 6 to 12 inches above the leaves*, 12 to 16 hours a day, following natural day length. General rule of thumb is that a Phal’s leaves should be granny smith apple to olive green. If they are darker, it means the plant is not getting enough light; red tinged leaves can mean the plant is getting too much light**. An easy way to measure light intensity without a meter is that no shadow should be seen if you hold your hand one foot above the leaves.

Once the plant is in bloom you can place it anywhere in your home out of direct sunlight to enjoy. It can tolerate a little while of decreased light. If your plant does not re-bloom, increase the amount of light that it receives.

*height above the leaf canopy depends on the light intensity you’re providing. Stronger lights should be farther away.

Phals are easy to grow because they enjoy the same temperatures we do – above 60º F at night and a range of 70º F to 80º F or higher during the day. 95º F is the maximum temperature recommendation. For most “big box/grocery” store Phal types (Phalaenopsis, subgroup phalaenopsis), a 10-15 degree overall temperature decrease (down to 55-60F) is desirable for three or four weeks in the autumn to initiate flower spikes. Example: if you normally have day temps of 80F and night temps of 70F, your average grow temperature is 75F. You would want to decrease this to 70F day and 60F night temps for average grow temp of 65F. This overall temp decrease has been tested by a few Japanese studies in recent years and proven effective for many Phalaenopsis subgroup phalaenopsis types.

Novelty Phalaenopsis (species and hybrids made with Phals from Phalaneopsis subgroup polychilos, are heat-lovers. They tend to be called the “summer bloomers” because that is when most growers get warmest temperatures. Oftentimes, if you can keep temperatures at 75F or above, novelty phals will continue to bloom in the “off” months. An easy way to do this in the home is to set them on heat mats that have a thermostat controller- keeps heat where you need it, but doesn’t cook the root system.

Even though they have thick, waxy leaves, Phalaenopsis will definitely appreciate humidity being between 50 and 80 percent. They will tolerate lower levels, but will do best in the range listed above. In very humid climates, as in greenhouses, it is imperative that the humid air is moving to keep nasty infections at bay. In the home, you have a few solutions to increase humidity: 1) set the plants on trays of gravel, partially filled with water, so that the pots are not sitting in water 2) group plants together to increase local relative humidity 3) plant in an unglazed clay pot and then nestle that pot into another unglazed clay pot (Credit to Neill Sams of Orchid Alley Kauai for this idea) 4) add a humidifier to your growing area (I personally like ultrasonic humidifiers for indoor growing)

Best done in the spring, immediately after flowering, but they can technically be repotted at any time. If done gently, it is possible to repot with open blooms, but you run the risk of shortening the bloom cycle duration, so usually easiest to wait until done blooming. Phalaenopsis plants must be potted an aerated media- porous bark mix or sphagnum that isn’t overly compacted. Potting is usually done every one to three years. Mature plants can grow in the same container until the potting medium starts to decompose, usually in two years. Root rot occurs if plants are left in a soggy medium. Seedlings usually grow fast enough to need repotting yearly, and should be repotted in a fine-grade medium. Mature plants are potted in a medium-grade mix. To repot, remove all the old medium from the roots, trim soft, rotted roots, and spread the remaining roots over a handful of medium in the bottom of a new pot. Fill the rest of the pot with medium, working it among the roots, so that the junction of the roots and the stem is at the top of the medium. Most “box store” Phalaenopsis are potted in sphagnum moss and usually will benefit from immediate repotting once done blooming.

Cutting the spike: Always cut with sterilized tools. When the blooms are finished, you can cut the spike down to where it emerged from the crown and the plant should bloom with larger flowers and a strong stem in the next year. You can also cut off the stem leaving two nodes (those little brown lines on the stem below where the flowers were) on the stem. One of these nodes will then initiate and generally produce flowers in the following months. For some “ever-blooming” species and their hybrids (Phalaenopsis subgenus polychilos), it is important to not cut the flower spike until it turns brown because it can flower for years off the same spike. At times, I will cut an ever-blooming spike before it browns if I want the plant to focus on leaf and root growth instead of flowering.

• It is also important to note that some Phals that are in box stores have been forced into a bloom cycle, so it can take 12-24 months for a Phal to resume blooming once it has returned to its normal, biological cycle (without much artificial influence, like putting in a chilling house).