Nancy, quick check shows coffee grounds/coffee is considered a fertilizer in and of itself. I would think if what you were adding to the coffee didn't double or triple up on any component that might be TOO much, it would be just fine.
General from the web: "Used coffee grounds contain about two percent nitrogen, about a third of a percent of phosphoric acid, and varying amounts of potash (generally less than one percent). Analysis of coffee grounds shows that they contain many minerals, including trace minerals, carbohydrates, sugars, some vitamins, and some caffeine. They are particularly useful on those plants for which you would purchase and apply an “acid food,” such as blueberries, evergreens, azaleas, roses, camellias, avocados, and certain fruit trees."
