Bob Hobden wrote:
Paraffin will have some effect on the mice but we haven't found anything
works except planting them in compost in square shaped guttering raised up
well away from mice. Once the plants are well into growth you slide the lot
into a pre-made drill and away they grow. If you have to buy the guttering
it's not cheap but it will last years, decades even, if you are careful.

I've found we've lost more to over-paraffining than mice anyhow.

We have started the guttering method, and it works well, although it's
always a pain to transfer into the ground, as they start growing through the
drainage holes! Ours was cheap enough - my uncle was clearing a building
site and we got throw-away stuff for free. :-)