Matthew,

My general rule of thumb is:

Violaceas and bellinas (and some of their hybrids) bloom for me in the summer and fall. Other orchids generally bloom in the late fall/winter/early spring. Shorter days and a 15-20 degree temp drop at night in fall usually cause spikes to form on most non-summer blooming phals.

There are obviously exceptions to these rules.

Good luck,

Bob