Nitrate of soda for blueberries??

I've heard not to use . . . yes or no???

Nope, we don't put that on our BB bushes, we do use epsom salt on them though. :)

I was told that sodium was toxic to blueberries ;-o

Been growing blueberries for 20+ years, every year we burn the grass around them and sprinkle epsom salt at the base. Let the rain wash it into the ground slowly, never had a problem and always a good crop of berries. The other thing I do is rake the pine needles up and place them as a mulch around the bushes. They love the acid the needles provide.

This may be some help top you :)
http://www.homeorchardsociety.org/article/40/