This time last year, I planted two blueberry bushes in half barrels.
I ammended the soil with granular soil sulfar to reduce the PH, and
continually top dressed the soil with coffee grounds. After a while,
the soil took on a pungent sour smell, the leaves became brick red and
brittle, and both plants died (at different times). The folks at the
nursery were no help in determining what happened. My best guess was
that perhaps the coffee grounds had formed a crust on the surface of
the soil, and created an anerobic soil condition which killed the
plants.

I want to try blueberries again this year. Should I dispose of the
soil in the half barrels and start fresh, perhaps with a commercial
Azelea mix? Any other tips to share?