I last used Morgrow Bat Guano (organic) on my orchids (and tomato plants
too). I have also used another brand of the same (Whitney?) with good
results. One thing about this fertilizer is if it isn't washed off some
of the leaves, I have not found disastrous results. I used but once
time a dry granule-type product that nearly wiped-out my collection. I,
therefore, am an avid user of the old spray bottle and the types of
fertilizer concentrates that can be applied per the same.

.. . . Pam
Everything Orchid Management System
http://www.pe.net/~profpam/page3.html