Rupert wrote:

Interesting:- Looks like JI ericaceous is similar to JI seed compost .The
difference is that limestone is replaced with sulphur to give a higher pH.
I have never used JI but I suppose perhaps I end up making something
vaguely similar by mixing soil with bog standard seed and potting compost.



Make that a LOWER pH. pH7 = acid pH7 alkaline. p stands for 'minus
logarithm to the base 10', and H the concentration of hydrogen ions (if
you are interested). So the higher the H+ concentration the lower the pH