Rob from Virginia here. I'm no blueberry expert, but I think that soil
acidity and testing might be important. The extension office here worked
with a local blueberry farm and found that they had the soil too acidic.
They actually had to apply lime to bring it up a bit. They had gone too far
the other way than usually is assumed.
I had one planting of blueberries that was a failure, so no direct
knowledge!