Hello Jon
You are right that blueberries need an ericatious soil. For creating
a potting mix a mixture of peat, sharp sand B & Q soil improver (which
is shredded pine foresty waste) and top soil (so long as not a lime
soil) at a ratio of 1:1:1:1 works well.
The pond does want puncturing, blueberries are not aquatic plants -
they will drown. Equally they die if allowed to dry out. Pre packed
ericatious compost tends to be too peaty and stays wet - could use it
as a base material instead of the peat.
Blueberries are grown commercially in the UK from Dorsert to East
Anglia where the soil is free draining. The crops are heavily mulched
with foresrty waste and watered once the top inch starts to try out.
I know some people say that you should not water with tap water if the
water is hard - leaves lime deposots in the kettle. However I have
not had a problem - just counter with a dilute ericatious feed.
MirAcid tends to burn the fine roots, so I avoid that - Chempack or
Vitax ericatious feeds seem fine.
Regards
Clifford
Bawtry, Doncaster, South Yorkshire