There are various fertilizers sold that acidify the soil. It is a temporary effect as soil has considerable pH buffering capacity. I grow blueberries in wine barrels and that seems to work pretty well. It also makes picking the berries easier. A few years ago the blue jays discovered the berries and I now install bird exclusion netting as the berries approach ripeness. Once the berries are picked for the year, I disassemble the apparatus and store it out of the way.
