Quintessentially British, runner beans are one of the easiest vegetables to grow and are a delicious garden staple. Most varieties grow very tall and will produce colourful red, white or bi-coloured flowers. Shop bought runners can be tough and stringy, but growing and picking your own will make you see them in a new light. To many gardeners, summer is incomplete without them.
Runner beans need a warm, sunny spot in well-drained soil. This kind of position also benefits pollinating insects, which are essential for the beans to set pods. Fork in some well-rotted manure, in late autumn or early winter, before you sow your beans.
Runner beans are tender and don’t like frost, or cold temperatures, so wait until May or June to sow the seeds. It is best to start the beans in small pots, and sow two beans per pot 5cm (2in) deep (only plant the strongest plant). Place the pots outside in a coldframe, or in a sheltered position. Once the beans reach 8cm (3in) tall you can plant them out into their final positions, this will be about June or July.
Alternatively, if you have room, start the beans off indoors on a windowsill or in a propagator, as above, but you can sow in April. This will give an earlier crop, but be alert for cold weather once you plant them outside.
Runner beans need a support to climb up. The traditional method is to grow them individually up inwardly sloping 2.4m (8ft) tall bamboo canes tied near their top to a horizontal cane. If you slope the bamboo canes so that they meet in the middle and tie them here so that the ends of the canes extend beyond the row you will find picking is easier and the yield is usually better.
When growing in beds and borders a wigwam of canes takes up less room and helps produce an ornamental feature.
Loosely tie the plants to their supports after planting; after that they will climb naturally. Remove the growing point once the plants reach the top of their support.
Keep an eye out for slugs and blackfly that may attack the plants.
Runner beans sometimes fail to set and there are a number of causes – and a number of solutions.
Ensuring the soil is constantly moist and doesn’t dry out is the first key to success; mulch the soil in June. Misting the foliage and flowers regularly, especially during hot and dry weather, will increase humidity around the flowers and help improve flower set.
Flower set is better in alkaline, chalky soils. If your soil is neutral or acidic it pays to use lime.
Another way to improve flower set is to pinch out the growing tips of the plants when they are 15cm (6in) high. The flowers formed on the resulting sideshoots usually set better.
If you regularly have problems it would be worth growing pink or white-flowered cultivars, such as ‘Painted Lady’ or ‘Mergoles’, which usually set pods more easily.
Troubleshooting Growing Problems
Aphids: Look for colonies of greenfly on the soft shoot tips of plants or on leaves. They suck sap and excrete sticky honeydew, encouraging the growth of black sooty moulds.
Remedy: Use your finger and thumb to squash aphid colonies or use biological control in the greenhouse.
Slugs and snails: These feed on the young seedlings and you’ll see the tell tale slime trail on the soil around your crop, as well as on the leaves.
Remedy: There are many ways to control slugs and snails, including beer traps, sawdust or eggshell barriers, copper tape and biocontrols.
No/ very few beans: This is one of the most common problems of bean growing and is usually caused by lack of moisture and/or poor pollination by insects.
Remedy: Plant or sow beans into soil that has had plenty of organic matter, such as well-rotted manure added the previous autumn, as this will aid moisture and nutrient retention around the roots. Plant in a sheltered site as this will encourage bees to visit and pollinate the plants.
Lettuce is ready to cut when a firm heart has formed, or the for loose-leaf varieties when leaves are big enough to be worth eating. Harvest lettuces by cutting rather than pulling.
Plant with: broccoli, brussels sprouts, cabbage, carrots, cauliflower, celery, chinese cabbage, corn, cucumbers, eggplants, garlic, kale, kohlrabi, peas, potatoes, radishes, strawberries, swiss chard