Penninetal, that's exactly how I grow my runner beans......deep trench and empty contents of my compost heap in and rake soil back. Get huge quantities of beans. Should work in containers .... Bigger the better with a wigwam of bamboo canes tied together very securely at the top and watered well. For early crop sow in trays indoors, move into pots in cold frame, etc, plant in the container and cover with fleece until danger of frost has gone