Sue, I think the advice of manure and sulphate iron was to make a better soil in the long run. It's to amend the soil before planting anything in it.
Here is a picture of the bed, as you can see on the left is not really divided, under the rocks it's a whole thing with the rest. On the right there's no soil, at least as deep as I can see, because there starts the alleyway (common to all the apartments).
I will add manure or compost, adding organic matter seems the best way to go, I just read this article and it says to avoid peat:
http://www.ces.ncsu.edu/depts/...
javaMom, many thanks for your advice, the potting mix I was talking about has a german/holland name maybe it's the same thing!
