I like to grow overwintering broad beans in a greenhouse or a polytunnel as I find that in a very cold and damp winter young plants outside are prone to rot. I sow broad bean seeds into loo rolls filled with used compost towards the end of October. Once the seedlings emerge after three or four weeks I plant them out in double rows 20cms apart. Keep moist but do not overwater. They will continue to grow slowly through the cold winter months and by early March the first flower buds will begin to show, followed by clusters of flowers which are a magnate for bees foraging for nectar in early spring (leave the polytunnel doors open to let them in). No loo rolls? Then just sow directly in the ground, 2 seeds together 2.5cms deep in a double row s0cms x 20cms apart. When the seedlings emerge thin out the weakest plant at each station. With luck I am harvesting the first young beans in early May.