Once that hot steaming mug of fresh coffee is poured, Most people don't give their coffee grounds a second thought. Check out these clever uses for coffee grounds Fertilizer: Coffee grounds are highly acidic, so spread them generously over the flower beds of acid loving plants for amazing blooms. Acid Loving plants include azaleas, rhododendrons, blueberries, Hydrangeas,lily of the valley, roses and creeping phlox.