A common way to fertilize container gardens in general, and orchids in particular, is to follow the maxim “weakly, weekly.” This means to fertilize them at a weaker strength than recommended on the package, on a weekly basis. A good rule of thumb is 1/4 strength. A lot of orchid fertilizers are synthetic. If you want to keep things organic, one thing I’ve found that works pretty well for orchids is a weak worm tea. Check out a product called TerraCycle Orchid Plant Food if you don’t have your own vermicomposter or just don’t want to have to make it yourself.