Add in some composted coffee grounds.[1] Coffee grounds can be mixed directly into the soil or added to a pre-established compost pile. The grounds contain about two percent nitrogen by volume, which is considered fairly high as far as nitrogen-containing materials are concerned. Additionally, while some worry about the acidic properties of coffee, it is the coffee beans rather than the grounds that contain high levels of acid. Coffee grounds that remain after brewing are usually between a pH of 6.5 and 6.8, which is near neutral.
You can add coffee grounds directly to the soil by mixing damp grounds into the soil or by spreading the grounds over the surface of the soil and covering them with organic mulch.