The message
from Jane Ransom contains these words:

In article , Janet Baraclough.
. writes
With loads of mulch, manure and no chemicals, the place is
now heaving with earthworms. (NZF's appear to have been successfully
eradicated).

What a success story
What did you do to eradicate the NZFs?

Search and destroy :-) They lurk on surface soil, usually in groups,
always underneath some kind of shelter like pots or stacked turf, and
don't wriggle away like earthworms do in the same situation, so it's not
hard to find their hiding place and evict them. Horrible looking things
they are, a bit like leeches only much less lively. I just crush the
buggers to a smear on concrete, with my boot.

Janet