It was a dark and stormy night, and as the people of uk.rec.gardening
huddled around the fire, Jim W told them this story:

The ususal time to do this is Autumn. your a little late this year, but
its still worth doing if the ground isn't frozen.

For peas/beans you can also put up to 3 folded newpapers (broadsheets
woerk well) soaked in water, at base of the trench.

My gardening book gives me a crop rotation system in which legumes
follow brassicas, so that the nitrogen-fixing replenishes the soil after
the brassicas have eaten up all the good stuff. But I obviously can`t
start digging trenches when my sprouts are still in full swing and the
broccoli hasn`t even got going yet! Perhaps I should be using some
other rotation system..


Rhiannon, only got three beds (well, two, but one is long and thin and
so can by split down the middle), but with such clayey stoney soil has
given up trying for root veg, so only three crop groups..