what joanna said. right now, i think the hygrometer says 42%
downstairs. i've got 2 (maybe 3) phals and one vuyl in spike. we get
NOID phals at the office for the reception desks, and the humidity there
can drop as low as 25% (yes, i've brought a hygrometer in to the office
to try and make a point to the building engineers. :-) they keep
blooming just fine.

now, if you were to do something like take the plant from a 65 degree
house out into 45 degree weather for three hours and bring it back in,
you might have a problem. but the humidiy shouldn't do anything drastic.

--j_a