Phil L wrote:
[...]
Thanks but was trying not to spend much (if any!) money...I've
decided on roof slates about a foot wide and two foot long, buried
about a foot deep giving me a foot above ground? - I can get slates
for free and I'll only need about twenty, I'm just wondering if
they
will effectively hold the soil back or if it will leak through the
gaps? - our soil is very fine and sandy.

Nice recycling! But one word of caution: a slate on edge in the
ground can give a nasty gash to anybody who happens to fall on it.
Opened a finger to the bone when I did it.

--
Mike.