On 25 Feb, 20:05, "Tim W" wrote:
I want to cut a small bed from the lawn near the kitchen door to grow a few
culinary herbs. The bed will be at waist height because the lawn is up
behind a retaining wall. The subsoil is solid red clay. The position is a
good sunny spot in SW uk. I want to plant mediterranean type Herbes de
Provence which I believe require a sandy well drained soil which I
absolutely do not have. The size of the bed will only be say 6' x 2' so I
don't mind a bit of digging out or buying sand or loam, but what is the best
way to ensure drainage between the wall and the clay, and what is a good way
to mix or obtain the correct type of soil (whatever that is)?

It would have been great if you could have done this in the autumn,
but there's still time to dig in and let the soil open to the elements
for a few weeks, let the rain work on the clay clods. Then add plenty
of organic manure, or your own made compost or mushroom compost. Well
drained is the key here and the om will help with breaking the clay.
That would be all I'd do for herbes.