Hi Barry,
You don't mention all the conditions. You say full sun - where? There's a
big difference. How about humidity? Low humidity could cause the bloom stem
to blast and keep the others from blooming. What medium are they in? Some
vandas are totally intolerant of heavy medium and must be in a wooden
basket with maybe some cork, charcoal chunks, or pumice to stabilize them.
Most vandas appreciate being watered daily which means the drainage must be
absolutlely perfect. A couple of possible suggestions:
1- The bloomer may be precosious. It may a species or hybrid that blooms
younger than the others. Are the blooms smaller as in ascocendas? Some
vandas just need to be larger in order to bloom.
2- It may be a species/hybrid that blooms in lower light than the others.
are any of them terete (pencil-shaped leaves). Some flat leaved varieties
will bloom in lower light than others. Terete-leaved varieties will be very
difficult to bloom in northern areas or under lights.
Good luck
Gary

"Barry" wrote in message
ink.net...
I have a potted vanda that was purchased 2-3 years ago from RF. At $125
its
the single most expensive
orchid plant purchase we've made. OK, I'm cheap, but the mortage comes
first.

The plant consists for three potted vandas around a tree fern pole,
they've
at least doubled in size
since the purchase. Only one of the plants ever blooms. In fact I noticed
about a week ago that two new
spikes were developing on this one plant. One spike dried out before it
was
3/8" long, the other is growing nicely.

Why would only one of the plants bloom? They obviously get the same
fertiler, they're all in close to full sun.
Last year it bloomed in sept and again in dec/jan. Hoping for two blooms
this year.