This is the mix you want to use for BLUEBERRIES.

E.B. Stone Organics Azalea, Camellia & Acid Potting or Planting is a versatile mix that can be used as both a soil amendment or as a ready to use potting soil. Our Planting Mix is a special blend of organic ingredients designed to meet the unique growing needs of most acid-loving plants. Additional plants we recommend it for include most varieties of evergreens, ferns, rhododendrons and begonias. Ingredients: aged fir bark, aged redwood, peat moss, pumice, feather meal, bat guano, kelp meal, and a wetting agent (yucca schidigera saponin).