Inducing blooms

[Fenix]

I know that the temperature should be dropped to induce blooming, but how do you know when your Phal is "ready" for reblooming?

I've had two new leaves grow and several new roots since the flowers fell off. When should I try to induce the blooming by dropping the temp?

Also Just wondering... if Phalaenopsis is a tropical plant, how come it needs to have a sudden drop in temperature to kickstart blooming? How would it bloom in the wild, since I don't think the temperature ever really drops about 15 degrees for extended periods of time although there are cooler times of the year.