Runner Beans are particularly sensitive to the cold, and even when temperatures are above freezing cold winds can damage runner bean plants, so don't be tempted to plant ouside too early.
For those that want an earlier crop, you can sow the seeds early indoors to get a head-start. Runner Beans are fast growers so there is no need to sow before the end of April. Sow a single bean seed in a large cell tray or a 9cm pot filled with good quality compost. Water, label and place on a warm windowsill to germinate. Runner Bean seeds usually will be ready to plant out after about three weeks. Before planting out, ensure you harden the plants off.
For later sowings, beans can be sown direct into their growing positions after mid May to the middle of June. Plant two seeds to each cane about 5cm deep. After germination remove the smaller, weaker of the two plants.
Runner beans prefer a moist, fertile soil in a sunny location that is sheltered from strong winds. Before planting, dig over the soil, and adding plenty of compost or manure. Then create a support for the plants to climb up. Either make a wigwam with canes, or a row of canes. Each row should be 60cm apart and canes spaced 15cm apart in the row.
Beans can also be grown in containers, all varieties are suitable for this, but if you lack space choose 'hestia' a dwarf variety that doesn't need support. Use pots at least 40cm wide and make sure there are plenty of drainage.
For Runner Beans plentiful watering is essential. They should be watered particularly heavily, and twice a week in dry weather, especially when the flower buds appear and once they're open to aid flower set. Because Runner Beans are shallow rooted, don’t hoe around the plants too deeply as you may damage the roots. Feed regularly, but choose a feed low in nitrogen - bean plants produce their own from the soil, so is not necessary.
Runner beans are pollinated by insects, if you have problems growing beans, due to poor harvests, we suggest you try the variety 'moonlight' - its probably as close to self fertile as will get, and is well regarded.
Regular picking of the beans is essential - the more you pick, the more they will produce. Runner beans are at their best when picked young and tender. As the pods get older they develop a 'string' and become tougher. If you let them go to seed the plants will consider their jobs done and stop producing.
In a normal year, you should start harvesting beans from late July, with cropping continuing until the first frosts, or longer if the plants can be protected from the cold.