24ºC to 27ºC (75ºF to 80ºF) during the day
Not lower than 16ºC (60ºF) at night
In Victoria - this means you plants stay indoors in late Autumn to early Spring!
32ºC to 35ºC (90ºF to 95ºF) for faster vegetative growth (Summer yeah! But not in direct sunlight please)
18ºC (65ºF) at night for initiating flower spikes
Ok now this is the funny part - in Victoria this means that if you did your vegetative growing well, the plant should really flower into Winter.
In the tropical climates that farm phalaenopsis for the flower industry, they roll their plants on the growing racks into a 'chill room' (imagine a large wine storage warehouse) at nights. Hence the year round supply of phalaenopsis in the flower shops.
Shaded North, East or North East window is ideal in the home
South or West windows are acceptable
The idea is indirect sun or shaded direct sun (about 50% shade like what you would get behind a lacey curtain)
Light is easy to provide for Phalaenopsis. They grow easily in a bright window, with little sun.
Plants should be thoroughly watered and not watered again until nearly dry through the pot. But not quite as bone dry as you would do with Cattleyas. For my phalaenopsis, I like the medium to be damp enough for the roots to appear green when I look under the bark. Depending on what medium you pot with, the dampness and hence timing between waterings can vary substantially. Also it depends on how much 'expose' surface you have for the humidity to evaporate. But be very careful they are not wet! Dripping wet more than 2-3 hours after watering is not the way to go.
If potted with sphagnum moss I only have to water once every fortnight. If potted with coarse bark I water every 3 days. If potted with coarse bark with a fine bark mulch I only water once every week - I think you get the idea?
In the heat of summer in a dry climate, water the plant every 3 days
In the winter, water the plant every week
Water only in the morning, so that the leaves are dry by nightfall
When the plants are growing: Apply a 20-20-20 fertilizer.
When flowering is desired, 4 months prior spike initiation, STOP high nitrogen applications and apply a 10-30-20 Blossom Booster
Apply the fertilizer every second watering
Phalaenopsis plants must be potted in a well-draining mix, such as bark, coir, loss sphagnum moss, or combinations of these.
Potting is usually done every year after flowering. Mature plants can grow in the same pot until the potting medium starts to decompose, usually in 2 years.
To repot, remove the entire old medium from the roots, cut of 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 through the roots. Keep the plant shaded and humid, but drier in the pot, for several weeks to promote new root growth.
Cut the flower stem off from the bottom around 1" after all flowers fall down. After 4 months of vegetative growth you can treat with cool temperature (18ºC /65ºF) in the nighttime (if you can't wait for winter). The new flower spike(s) will be stimulated.