Unlike hardy broad beans, they require warmth and will not survive frost.
For early crops, in northern areas and on heavy soils, they are best raised in pots of multi-purpose compost and planted out in June.
Alternatively; sow outdoors from Week 20 to Week 28. See below
Given the right conditions, runner beans are easily grown and produce prolific crops of tender pods from July to September, and even into November if the weather is favourable i.e. mild and damp.
Water plants well during dry spells to set pods, (hot nights reduce pod set).
Week 8: Prepare trenches now if not done earlier, the site should be prepared well in advance of sowing / planting.
Take out a trench 300mm (12") wide, and 600mm (24") deep, placing the bottom layer on one side of the trench and the topsoil on the other.
Fork soil at the bottom 150mm (6") deep and spread a layer of well rotted manure or garden compost.
Break up the subsoil as you return it, mixing with it, a bucketful of farmyard manure to each metre (3ft) run and 60gms (2 oz) of bonemeal.
When returning top soil, mix in well rotted manure, and add 1 oz. of bonemeal per metre (yard) run.
Rake bed over thoroughly in each direction, but don't do this if the surface sticky.
Week 18: Form an 'A' frame* support by inserting two rows of inward pointing poles/canes that cross at the top and secure with horizontal cross piece.
*Special bean frames are also available from reputable garden centres.
In smaller gardens you can grow runner beans in growing bags set against a sunny fence or wall, or erect a wigwam of bamboo canes on suitable sites in the garden.
If growing in containers, choose pots at least 450mm (18") in diameter and make sure there are plenty of drainage holes in them.
Fill the container with a potting compost equivalent to Ji3.
Week 19: Prick out into individual 70mm (3") pots.
If ground conditions allow, sow two seeds 50mm (2")deep at the base of each cane of the frame/wigwam.
Once germinated thin the plants to one plant per cane.
Week 22: when all fear of frosts has passed, plant out in a warm, sheltered site in double rows spaced 500-600mm (18”-24”) apart, setting each plant 150-200mm (6”-8”) apart.
Rake in general fertilizer at 3oz (90g) per sq.m prior to planting.
A mulch of peat/compost or grass clippings 25mm (1") deep helps to preserve moisture.
Spray the plants with water when they are in flower to help the flowers to set, and pinch out the growing points when the plants have reached the top of their supports.
Allow a few beans to dry out on the plant/s and these can be collected (circa week 35) for use as seed the following year.
Runner beans cross-pollinate meaning, seedlings may not be true to type if other runners are growing nearby.
Week 42: Dismantle support frame if all the beans have been harvested and place in store for next year.