While Miracle-gro soil has some nutrients added, I’d suggest adding additional nutrients in the form of high quality organic garden food like Espoma Garden-tone.  Miracle -gro food isn’t organic and doesn’t do anything to help the health of the soil…the soil that feeds your plants.  In addition to nutrients, Espoma “tone” products also provide a compliment of beneficial soil organisms that help build the soil and release nutrients from the soil that might otherwise be unavailable to the plants.