Blueberry plants don't need much fertilizer. But I've always used an acid fertilizer to help drop the pH a bit since blueberry plants like a pH of around 4 which is quite a bit lower than our just under 7. For the past couple of years I've started using an organic based fertilizer but still hit the plants with a bit of chemical fertilizer from time to time. In our area, where the sand get so dry during mid to late summer, water is a much more important factor for these shallow rooted plants. Blueberry plants are by far our number one rated small fruit for growing at home. The plants have almost no pests and are virtually care free other than light pruning every few years and watering between rains.
Eclectic gardening style, drawing from 45 years of interest and experience. Mostly plant in raised beds and containers primarily using intensive gardening techniques. Alex