We're in East Anglia, which is technically arid.
I have no allotment, but a biggish dry garden.
The soft fruit and top fruit do very well, so we are self-sufficient in blackcurrants, redcurrants, gooseberries, tayberries, raspberries, plums (Does this sound like bragging to you? I don't mean to). This is because we collect all the shower water and use it on the fruit

Root and leaf veg are very tricky: they just dry out.
Broad beans are good, but peas never germinate.
So, I'm following the Antipodeans and trying hydroponics.