Chris French and Helen Johnson wrote in
:

Anyone know how do you tell if your soil is acidic?
You have a garden full of Rhoddies ?

B-)
Something a little more scientific is what I was thinking of!

You do a pH test on the soil.

Can you buy litmus paper at garden centres?
Or I suppose now there will be better, probably electronic, versions around
now....
I'll see if I can see one at ours