Some climbing bean varieties grow over 3m (10ft) and some are dwarf at around 35cm (13").  These plants need a growing season of about 100 frost free days and are happiest when the temperature is around 14-19 degrees C.  If the temperature is higher, together with a high humidity factor the flowers may cause the fruit to not set well.

The plants in the picture alongside are nearly ready to harden off before planting outside.

Sowing Runner Beans

Runner Beans are deep rooted and need moist, fertile soil to produce well, so prepare the soil by digging a trench about a spade deep and 60cm (24") wide into which lots of well rotted garden compost or peat should be dug.

It is important, before sowing to set up a method of support - this applies if you are growing in your greenhouse or outside.

Seed can be sown outside at end April, beginning May,once all frost risk has passed.  Sow in double rows 30cm (12in) apart and 5cm (2in) deep with about 10cm (4in) between seeds.  In colder areas, the seed can be sown indoors using Rootrainers propagation trays,( Sherwood or Fleet sizes) or under cloches in mid-winter.

They can also be sown in the Rowplanter and when ready for transplanting just slide the whole row out into the prepared trench with no root disturbance.  Seed sown indoors should be kept cool to ensure good germination and the plants should be hardened off and transplanted outside as soon as possible.

Looking after runner beans

Water if necessary and extra water at a rate of 25-11 litres/sq m twice a week  may be required in dry conditions and especially at flowering time  and mulch between rows with compost, but this should not be done in the wet.  If plants are cloched, remove the cloches when the plants touch the tops. Feed with a low nitrogen feed every 10-14 days.

Harvesting

Harvesting will depend on the sowing time and the weather. Pick  the pods when they are at least 17cm long and tender.  Keep picking the beans and this will prolong the cropping time of the plants.  

Pest and diseases

Beans are generally pest and disease free, but can be affected by blackfly, pea and bean weevils, chocolate spot and mildew.