This morning when I was watering, I noticed that many of my S/H
phals--more than 30-- have developed or are developing aerial roots
where I'd expect a spike. These are plants that previously did not have
aerial roots. Argh!

I looked in Mary Noble's Phal book, and she writes: "Along the sides of
the stem in the axil of each leaf are two or three tiny buds...these
buds are like little bumps. They are capable of developing into
flowering or vegetative parts." [ I assume that "vegetative parts"
includes "roots".] These buds remain quiescent until envronmental
conditions induce the plant to produce flowers or new growths. "

Okay, so why am I getting all these roots instead of spikes? Is the
plant merely reacting to S/H? Am I over-fertilizing? Am I doing
something else wrong? How can I reverse this trend toward roots instead
of flowers?

My primary fertilizer is Dyna-Gro Grow, 7-9-5, and the leaves do not
exhibit fertilizer burn. The plants look healthy, except that they are
not setting spikes. They are getting almost a 15-degree drop in
temperature at night.

Any help would be greatly appreciated.