nope, you do not need cool temps for flowers

[jldriessnack]

So, I hate to be that person, but I am going to be - most people, even practiced phal growers keep spreading nonsense about these orchids. I want to dispel one of them here for people interested in the truth behind their culture. Keep in mind, all my advice will pertain to windowsill culture ONLY - I do not use a greenhouse or any special equipment.

Inducing Blooms

It is simply not true that phalaenopsis requires a temperature change for blooming. By the way, William Cullina points this out in his book on orchids.

First off, in most of southeast Asia where these orchids grow, no such cold spells of 55-65F occur. In Borneo, night time temperatures are often over 75F, and in Malaysia the average temperature is usually above 75F as well - these are tropical, hot rainforest climates. I have watched dozens of phals bloom under all manner of conditions, from temperatures in the high sixties, to constant temperatures in the 80s and 90s. Phals bloom in every season too, there is no right season. I have had blooms throughout the year and I have big, stemmed phals that I don't even need to fertilize (12+ leaves).

Indeed, the surest way to cause bud blast is to suddenly alter temperatures while buds occur. There may be some species types that need such a cool period, but most phals found these days are complex hybrids that have so much genetic diversity it is ridiculous to suggest they operate like the species types.