Runner bean

The runner bean is not hardy where you are. It dies back above ground with the first frost. You can either treat it as an annual and sow anew in spring, or dig up the fleshy root tubers in autumn, cut back the foliage and store the tubers cool, dark and lightly moist in sand or soil (like dahlias); from mid-April you plant them out again, and they then shoot earlier.

In a Central European home garden, you propagate the runner bean mainly by sowing; in addition, you can keep it going vegetatively via its storage roots. Sowing: from mid-April, start it off on a windowsill. Place one seed about 3 to 5 cm deep in each pot of seed compost and keep it warm (at least 15 °C). If you want to speed up germination, soak the seeds in lukewarm water for 12 to 24 hours before sowing. From mid-May, after the Ice Saints, when frost is no longer a risk, you can sow straight outdoors or plant out the plants you started indoors. Choose a sunny spot with a climbing support set up (canes, obelisk, fence) and place the seeds 30 to 50 cm apart, with 80 to 100 cm between rows. Beans usually germinate within 7 to 14 days. Saving your own seed is easy: let a few pods ripen and dry completely on the plant, then remove the seeds and keep them dry and dark until the next season. This gives you offspring true to variety. Vegetative propagation via the root (division/overwintering): unlike the annual French bean, the runner bean forms fleshy storage roots, which you can overwinter like dahlia tubers. In autumn, before the ground freezes, cut the vines about 20 cm above the root and dig up the root. Store it in damp sand or sandy soil, cool, dark and frost-free (cellar), keeping it lightly moist from time to time. From mid to late April you replant the root, one per climbing pole, and cover it with mulch. Older, strong roots shoot particularly vigorously and flower earlier than freshly sown plants; a large root can be divided when replanting. This way a proven plant is kept going for years.