"mark" wrote ...
I've just started a potato barrel.

It is open at the bottom and sitting on wire netting to filter out rats.
I've started it with about 9" of compost then dotted spuds over that about
4" apart.

These have been covered with about 3" more compost.

The compost is from a large and old compost heap. The potatoes are ones
from the kitchen cupboard that have started sprouting ( no rolling of eyes
please!). I was proposing to build up the compost as the potatoes tops
grew.

What nutrients can I add to enhance the crop?

I have wood ash from a wood burner, would that help if I mixed it with
future additions of compost.


4 inches apart? Normal spacing is about 15 to 18 inches minimum.
Chicken manure pellets are excellent, or Growmore, but don't overdo it as
your compost should already have all the nutrients they need (and more).
I would add the wood ash to the compost heap.

--
Regards
Bob Hobden