Creating a trench for runner beans

My allotment neighbour, David, a sprightly 84-year-old, suggested I get going on a bean trench when I went up to the site yesterday. Good advice as the soil was mostly too wet to dig, but I could dig out the trench from the side path without treading on the soil. It wasn't too hard as I had already dug most of it over in the autumn. Here's how it should look (on the left) and how mine does look (shown below) - not quite so photogenic! Since I should have started this a few months ago I plan next weekend to dump in my current kitchen scraps plus a bag of well-rotted manure from the garden centre (as I don't have any compost yet since I haven't been diligent enough in collecting kitchen waste over the winter due to the need to drive it up to the allotment site from home). For more info on how to build one see the Garden Organics page on trenches. What that page does not say, however, is that it is helpful to put newspapers or cardboard at the bottom of the trench, as this retains moisture. David also suggested that if you don't have manure or kitchen scraps, to put in upside-down turfs (turves?) i.e. chunks of grass with the soil stuck to it that you dig up from elsewhere, which I did, then covered with a bit of compost.