Charlie Pridham wrote:

All sorts of stuff in reply. I'm surprized no one has mentioned leaf
mould. I mix leaf mould and riddled turf loam, a little extra
horticultural sand. I used to sterilise small amounts for seeds, but don't
bother now. Yes you get flush of weed seeds - but they can be weeded.
Costs very little other than a bit of organising and I've always got
plenty. No air miles or peat bothering either!

Quite agree but can not produce enough!

My neighbours & family give me their bags of leaves in the autumn to
suuplement my own "crop". I've also been known to collect leaves from the
public footpath before the council gets round to it (not difficult :-).