Growing Runner Beans
Runner beans provide a succulent summer and autumn crop that is at its best just as the earlier dwarf French beans approach the end of the season. Runners are larger, coarser and have more flavour than French beans, but are slightly less hardy.
Although quite easy to grow, they produce a heavier crop if sown in well-prepared ground, and if the soil is kept moist during dry weather.
They are often called scarlet runners, because most of the common varieties have flowers of that colour. But there are other varieties — both climbing and dwarf — with white or red-and-white flowers.
Planning the crop
Runner beans, grow best in a sunny position, though with as much shelter as possible to encourage the insects needed to pollinate the flowers. They will grow in most garden soils, but do best in rich, well-drained ground. Runner beans need a deep, well-manured bed to allow maximum root development.
A month or two before sowing, dig a trench 18 in. (455 mm) wide where you plan to sow the crop.
Remove the top spit of soil and fork a generous dressing of rotted compost or manure – at least a bucketful per square yard – into the 6 in. (150 mm) of soil beneath. Replace the topsoil, first marking the centre of each end of the trench so that you will know where to sow. Any surplus soil can be banked along each side of the trench, where it will help to retain water.
If you plan to grow the beans in a circle, bury the manure accordingly and mark the site with pegs.
How much to grow
A 20 ft (6 m) double row of climbing runners, grown on well-manured ground, should produce up to 80 lb. (36 kg) of beans between July and October.
The yield will be considerably lighter if the plants are dwarfed by pinching out their tips.
`Enorma’: an improved strain of ‘Prizewinner’; long pods of fine flavour.
Try’: white flowers; heavy crop of stringless pods; flowers set well in dry summer.
`Kelvedon Marvel’: the earliest of all, varieties; can be grown as a bush by pinching out the tips.
`Streamline’: very heavy, reliable cropper; thick, fleshy pods.
`Yardstick’: exhibition-length pods; good for freezing.
How to grow runner beans In the south, sow runner beans outdoors about the middle of May – or a week or two earlier if you are prepared to sow again should a late frost kill the plants. Under cloches, sowing can be advanced to the second half of April.
For an even earlier crop, raise the seedlings indoors , or in a frame or greenhouse, by sowing in boxes of seed compost about the middle of April. After hardening the plants off, plant them out towards the end of May. If you are to plant the beans out under cloches, sow in early April.
In the north, delay these sowings and plantings for a week or two.
To grow plants up poles or canes, push the supports into the ground in two rows about 18 in. (455 mm) apart. Set the poles in facing pairs, with 12 in. (305 mm) between adjacent supports, and insert them at an angle so that each pair of poles crosses at about the halfway mark.
This is rather lower than the crossing point usually recommended, but ensures that pods on the upper parts of the plants, where growth is thickest, hang outwards and are easily seen. Tie additional poles horizontally at the crossing point to brace the structure.
Runner beans can also be supported by netting – plastic, string or wire – and in this case should be grown in single rows about 22 ft (760 mm) apart. Staple the netting to 2 x 2 in. (50 x 50 mm) timber uprights, spaced about 3 ft (1 m) apart along the row, with a strand of heavy-gauge wire along the top.
Yet another way of growing runner beans is in the form of a maypole. Insert an 8 ft (2.5 m) stake in the centre of each circle, and attach strings from the top of the stake to pegs hammered into the soil about 2 ft (610 mm) from its base. Allow 2 ft between pegs, and tie the strings in a half bow so that they are easy to undo if they become slack and need tightening.
Canes can be used instead of the strings, if preferred, and the centre post omitted. Tie their tops together, wigwam-fashion.
Sowing the seeds
Whichever method of support is chosen, sow two seeds 2 in. (50 mm) deep beneath the foot of each pole or string, or at 12 in. (305 mm) spacings along the netting, and remove the weaker of the pair if both germinate. Use surplus seedlings to fill gaps where neither seed germinates.
Alternatively, sow only one seed in each position, but sow a few extra at the end of each row for filling gaps.
Immediately after sowing or planting out, scatter slug pellets over t lie bed.
Watering and spraying
Frequent watering is needed to keep runner beans growing during dry spells, and it is important not to let the soil dry out completely once the flowers appear. A thick mulch of compost or lawn mowings, applied when the ground is wet, helps to retain soil moisture.
While the plants are flowering, spray them daily with water during dry weather — preferably in the evening. When they reach the tops of the poles or netting, pinch out the growing tips to encourage the formation of side-shoots and to prevent the heads of the plants developing into a tangled mass.
After the crop has been harvested, cut down the spacings leave the roots in the ground as they add nitrogen to the soil.
Pests and diseases
Runner beans may be attacked by Bean seed fly, Black bean aphid and slugs and snails.
The most likely diseases are Chocolate spot and foot rot.
Pick the beans while they are still young and tender, before the seeds begin to swell in the pods. The more they are picked, the more the plants will produce. For this reason, always remove large beans that have been overlooked.
When pods cannot be used immediately, stand them in a cool place with the ends of their stems in shallow water.