Miracid fertilizer is a water-soluble granulated fertilizer used for acid-loving plants such as hydrangeas, azaleas, rhododendrons and camellias. It is used to promote strong root development and larger, earlier blooms.
To better explain its use, Miracle-Gro changed the name of "Miracid Plant Food" to "Water Soluble Azalea, Camellia, Rhododendron Plant Food." Blueberries, gardenias, magnolias, orchids and holly benefit from the application of Miracid. Although these acid-loving plants do well in acid soils with a lower pH, they need the addition of sulfur or Miracid when grown in alkaline soils with a higher pH that does not allow the plants to process available iron. Miracid, applied either as a drench around the plants or as a foliar spray, lowers the soil pH, allowing the plants to take up iron more effectively.