alan.holmes wrote:
About a week ago I planted some seed potatoes, which had started to sprout,
but there is no sign of any growth yet, am I being too impatient?

Yes.

How long should they take before showing growth above the ground?

Depends on warmth and moisture. My pink fir apple (not strictly a
potato, mind) have grown arond an inch during the last week. They are in
a big plastic tub, in full sun by day, with a sheet of glass over them,
and in the greenhouse by night.

--
Rusty