In the past i fertilized with every watering, using a dilute solution but then I realized that there is a lot of salt accumulation inside the mixer part that prevents the solution to mix with a flow of water. A lot of my plants were underfed as a result. Since last fall, I've been fertilizing all my plants once a week using an electric pump sprayer. I use 1.5 tablespoons of MSU RO water fertilizer for 12 gallons of water. It takes me about 60 gallons to fertilize my collection of about 500 plants. I've noticed that some plants enjoy more fertilizer, like bulbophyllums, some coelogynes, some Mexican laelias during summer months. To supplement them with extra food, I usually add a little bit of slow-release fertilizer into each pot. In the case with a mounted plant, I'm attaching a small fertilizer cup to the mount.