Hi, I am interested to know if you are using organic fertilizers on your orchids? If so, what kind and how often, liquid or granular, and what are the results?
You may want to try Worm Tea. It is usually available as a concentrate that you dilute about one to ten parts water and simply use it when you would normally water. It has low levels of all the nacessary nutrients and when applied to foliage it can act as an antibacterial/fungal. I have used it on some of my vandas but I couldnt store it properly. It has live microorganisms in it which give it the anti bacterial/fungal properties so it must be stored inside a cool cabinet or they die and the tea looses its those properties and becomes just another fertilizer. Try looking for it at a hydroponics store or online.