Question From: J. Wasko - FLORIDA
Q: Vandas in distress. Once healthy blooming plants, emerging flower buds turn brown and black. Those that bloom have small and distorted flowers. Roots look vigorous and plentiful. Some leaves have black/brown tips. All hang outdoors, under roof eaves, none in pots. Water few time a week on roots only. Fertilize weakly weekly (1/4 strength) spraying roots.
John. I have no experience growing Vanda Orchids in Florida, but my guess is they are not getting enough sun and you are over feeding them. Google "growing Vanda Orchids outside in Florida in trees" to get more information, Also take photos to an independent garden center or nursery for a more accurate ID. Best And Happy Yardening, Nancy