I have already planted Blueberry bushes that are 3 years old. When they were planted the soil PH was around 6.5. I'm trying to get the PH down to 4.5. I added http://www.espoma.com/product/soil-acidifier/ this spring and they are down to a PH of about 6 at the moment. I live in New York and want to add more Soil Acidifier. Would it hurt to add more Soil Acidifier now being close to fall or should I wait for spring? I know you are not supposed to add Fertilizer in the fall due to the fact it may keep the plant from going into dormancy but I didn't know if the Soil Acidifer is considered a Fertilizer. Also the plants have mulch around them, Should I add Nitrogen in the spring along with Soil Acidifier or should you only add one or the other obviously the soil PH is the more important of the 2?