Fertiliser for my peas?

A few weeks ago I threw a few peas into a small recently cleared and completely unprepared piece of ground on the allotment. The ground is very dry and next to a walled area and as I hadnt prepared (ie composted or fertilised) the ground before do I need to feed my peas and if so what with? I am aware that I should avoid any nitrogen based fertliser as I belive the peas produce enough of their own. Please help