Using Gypsum will raise the pH, so I am not sure why that was recommended to lower the pH for blueberry. One thing that works pretty well is to add coffee grounds to the soil, and also add regularly as side dressing. In Davis, California, we had really alkaline soil and coffee grounds in the garden seemed to do the trick. You can pick them up at coffee shops who are more than happy to give them away
Using Gypsum will raise the pH, so I am not sure why that was recommended to lower the pH for blueberry. One thing that works pretty well is to add coffee grounds to the soil, and also add regularly as side dressing. In Davis, California, we had really alkaline soil and coffee grounds in the garden seemed to do the trick. You can pick them up at coffee shops who are more than happy to give them away