Making a support: Before sowing, construct a support system for your beans, as they are strong climbers. There are a number of ways in which you can train runner beans.  Have a look at what others do. 

We shall build a frame made up of a double row of six inwardly sloping 2.4m (8ft) tall bamboo canes tied near their top to form a long A-frame. These are secured to a horizontal  1.2m (4') cane across the top.  The structure is the width of a 1.2m bed and the two rows of canes are 60cm (2') apart  Have a look at the one we have made.  We will drape a bean net over this frame. As we did with canes for broad beans it is best to make 'pilot holes' with a metal rod to make it easier to push in the canes.

 

runner bean frame in the background

RHS Advice on Runner Beans

Sow the second week in May so, by the time the seedlings appear about 10 days later, all danger of frosts should have passed.

Sow your runner beans 5cm (2in) deep, two seeds spaced 15cm (6in) apart, later thinned to one seedling per station. When planting double rows, to match the double row of canes, space the two lines of beans 60cm (2ft) apart.  You will eventually have eight plants on either side of the frame so, planting two per station you will need 32 seeds; we will later thin to 16 seedlings.  Also sow a few seeds in modules in case replacements are needed.