I have found these methods of growing Phalaenopsis to be the best for my growing conditions. I grow in three environments: 1)inside the house in south-facing windows, 2) under lights (T8 and T12), and 3) in a glassed-in room on the north side of our house. I’ve been growing Phals for 15 years.
Natural Light: The best is early morning direct sun, followed by day-long indirect light of 800-1200 fc, Or, a south-facing window screened down to no more than 1500 fc in winter, and 800-1200 fc in the summer.
Brighter light for some species (See cultural notes for species phals).
T 12 fluorescent bulbs (1 ½ inch diameter): I use Philips Cool White, 48-inch, 40 watt bulbs with a color temp of 4100K, and light output of 3200 lumens. I have also mixed cool and warm bulbs, 4100K and 6500 K. Phals are placed with the leaves about 6 inches below the lights for 200-250 fc of light for 14 hours.
The smaller T8 fluorescent bulb: I purchased these last year and immediately burned some plants, even though my light meter read 300 fc. Place phals 12 inches or more below lights at about 200 fc, for 12 hours per day. New bulbs are stronger than old bulbs. Advantage is a little less electricity and more room to see and work with plants. Disadvantage is that you can’t get as many shelves on a plant stand since you’re placing the plants farther from the lights.
Very important to prevent fungal diseases. Don’t crowd plants. Place pots on a grid, wire rack, or other surface that will allow air to circulate underneath and into the bottom of the pot.
Pots and Media
In the beginning, I used bark mixes, but found it difficult to know when to water, and also found that many of the roots rotted. I now grow in Premium-Grade New Zealand sphagnum, with some amendments, especially for larger pots. Source: Cal-West Orchid Supplies
There’s no substitute for Premium Grade New Zealand spaghnum. Some of my larger Phals have been in the same media for two years and when I recently repotted them, the roots were very strong, healthy and no rot. The spaghnum was just beginning to break down. For smaller phals, I repot as the plants begin to outgrow the pot, preferably right after they are finished blooming.
My potting method:
First, soak the moss for an hour or more (over night is best), to get it well hydrated. Select a pot that’s just big enough to comfortably hold the roots, but not too large. Put a few rocks in the bottom of the pot. This is especially important if you are using a plastic pot as the plant will need a ballast to hold it upright when it produces an inflorescence. Trim any rotted roots. Place phal in pot with crown slightly above the top edge of the pot. Add Styrofoam peanuts to make a bed for the roots to grow happily in. Fewer peanuts for small pots (¼ of the pot), and more for larger pots (1/3-1/2 of the pot). Squeeze out the moss to be used. Place around roots. Don’t pack it in tightly, just firmly enough to hold the plant well. If you are working on a large phal in a pot that’s 4 inches or more, add some soaked medium bark pieces to give a mix with more air. Very important that the plant’s crown be above the sphagnum. I sometimes place a Styrofoam peanut just under the crown.
You are trying to provide a moist, but very airy environment for these orchids. Remember, they are not terrestrial. In the natural world, they grow on trees, not in pots. Don’t suffocate the roots.
From my observations, rain water is the best, supplemented with a good fertilizer that contains all the basic nutrients and trace elements that plants need. I use the Michigan State formula, ¼ tsp per gallon in the winter, and ½ tsp per gallon when they are in growth phase (Spring and Summer), three waterings in a row, followed by a flush with water without fertilizer. When rain water isn’t available, I use Reverse Osmosis (RO) water. All my Phals, and especially the species Phals grow better and healthier with water that is low in dissolved solids. Where I live, the rural water district reports that our tap water has an average of 185 ppm of total dissolved solids (tds). But when I look in the bottom of my tea kettle every morning, I suspect that the tds must be higher than that! The amount of mineral build up doesn’t just affect the taste of my morning tea, it can burn the roots of sensitive orchids. I observe better growth in the plants, and healthier roots and leaves on all of our orchids, as well as tropical houseplants and African Violets, after switching to RO water, and even better results by using rainwater.
Signs of mineral build up in orchids: Black tips on the roots, brown tips on the leaves.. Good water quality is especially important if you choose to use sphagnum moss as this media does absorb salts/minerals.
How often to water depends on your growing conditions. I water when the moss is almost dry. I put my finger down into the media to check for moisture. If it’s almost dry, it’s time to water. If I have waited too long and the moss is crisp, I run a lot of water (no fertilizer) or I will put the plant and pot into a bucket of water to rehydrate it. Water in the morning.
When you water, avoid pouring water into the crown. I carry some tissue/paper towels with me when I water and I blot up anything that left standing in the crown. I never put my Phals outside for the summer. It’s problematic and I don’t find it to be necessary because they are not high-light plants. I can control their conditions much better indoors.
Indoors in the winter, provide adequate humidity for your Phals. If you see shriveling aerial roots, the humidity is too low. Invest in a humidity gauge and aim for 40-70 percent humidity. If your house is dry in the winter, you can use a humidifier in the area to raise the moisture. You can also place plants on grids above trays of water to add humidity in the winter.
My phals all bloom beautifully each year by reducing the night temperature to 58-60 degrees, beginning in September for 3-4 weeks. The cooler autumn night temperatures will initiate the growth of flower spikes. Some species Phals don’t respond to temperature drop. See the Species Culture Notes. It’s also very important to reduce fertilizer; I switch from ½ to ¼ tsp per gallon and naturally as the temps drop I water less often because the plants are not drying out as rapidly.
If you wish to stake the spikes, begin this process when the spikes reach about 6 inches. They become more difficult to bend and shape the longer they get.
Species Phal Culture
As with many species orchids, water quality is very important. If you’ve tried species phals before without success, perhaps there’s a tip here to help you.
Doritis Higher light than Phals, 1500-2000 fc. Best to have overhead light when they go into spike in the Summer as
spikes can become quite tall. Reduce watering in winter. Bloom in late summer. Doesn’t require cooler night temps.
Phal bastianni This phal needs higher light, 1500-2500 fc , or almost Cattleya light if there’s good air movement. Reduce water in winter, but there is no dry rest period. Blooming is March-May. Don’t cut off old inflorescences as they can branch and produce more flowers and/or keikis.
Phal cornu-cervi This phal requires higher light to bloom, 1200-1500 fc summer, and 1500-1800 fc winter. Give light until leaves become light yellowish green. Reduce water in winter. Can tolerate cool night time temps. Summer blooming. Size: leaves on a mature plant 5-9 inches long.
Phal chibae This phal from Vietnam is a warm grower, with winter temps of 84-61 and summer a bit warmer. In habitat there’s a distinct dry period in winter and early spring. In cultivation, plants should dry out between waterings, and watering reduced for 2-3 months in winter to early spring. High humidity in summer and a little less in the winter. In the natural environment, light is highest in the winter, 2000 fc and more protection from sun in the summer. Bloom time is April through June.
Phal deliciosa (Kingiella philippinensis), Warm growing, with winter temps of 81day, 64 night. Dry rest in winter, reduce watering after new growths mature in the fall, and allow roots to dry between waterings.
Phal equestris likes 1000 to 1200 fc light in summer, increasing to 1200-1500 fc in winter. Some growers report that this species likes a drier rest period in the winter, but I haven’t found this to be true. Don’t cut old inflorescences as they can branch and produce more flowers and/or keikis.
Phal gibbosa, Reduce water in the late Fall for 2-4 months. Provide good humidity at all times. Does well mounted. Likes cooler winter temps with a high of 70 and low of 58. From Vietnam, near Hanoi.
Phal hieroglyphica This is a warm-growing phal that should never dry out completely. Winter temps are a bit cooler, but not below 61 degrees. This is a late summer and fall bloomer. It doesn’t need the temperature drop to initiate a bloom spike. Average Phal light of 1000-1200 fc. Don’t cut off the old spikes as these are viable for 4-5 years and will re-bloom as well as make keikis.
Phal lobbii and parrishii, Eastern Himaylayas, India (Assam and Sikkim), Myanmar, Bhoutan, Vietnam, flowers winter and spring. Hot, wet summers and dryer, cooler winters. Plant can be deciduous in the wild if exposed to cold and drier weather. If kept slightly damp in the winter, they will retain leaves. They require more light than most phal species. Grow mounted with 60-80 percent humidity. Fragrant. Spritz only in the winter.
Phal mannii, This phal needs very low light, 800-1,000 fc, and a 3-5 month cool, dry rest with misting only. Winter temp: 70-80 with nights 46-56. Increase light a little in winter. Flowering is initiated by rest period.. Grows well mounted.
Phal pulchra needs high light, almost Cattleya light to bloom (2000-3000 fc), otherwise only produces keikis. Give light until leaves are light yellow-green. Don’t cut off inflorescences as they will re-bloom for several years. Plants produce long inflorescences with keikis common and only a few, long-lasting waxy, bright dark pink flowers in the summer.
Phal schilleriana has a distinct rest period of 2-3 months in the winter. No fertilizer. Keep media on the dry side druing this period. Water less frequently. Plant can go dry between waterings, or if mounted, just mist roots. Too much watering and the roots will rot. A little higher light in winter, 1500-1800 fc. This phal flowers during the cooler, drier period.
Phal stuartiana This plant needs to be kept warm, not below 62 degrees. Don’t water with cold water. Does not need a dry rest period, but reduce watering somewhat during winter months.