Are you working with phals?
Someone had this great idea of using molasses, K-L-N rooting hormone and classic jack's fertlizer for helping out rootless vandas. The molasses has potassium which I guess helped them stimulate root growth. They would mix all this stuff together and use it with their watering regimine.
Are you growing on a windowsill, greenhouse, orchidarium? Let us know cuz there might be some things you can do to tweek the humidity levels/light levels.