Runner beans: wait for May, then put the canes up first

Runner beans can’t take any frost, so they go in late. In the UK, sow them indoors from late March to late April, or outdoors from early May to late June, and plant out indoor-raised plants from early May to early June.

Indoor sowings give the earliest pods, from early July. Outdoor sowings in late May or June crop later but often catch up, and they’re useful for extending the harvest into October.

Sowing indoors

Sow one bean per 8 cm pot or deep module, 5 cm deep, in multi-purpose compost. Keep them somewhere warm and bright, such as a windowsill or greenhouse. They usually come up within a week or two.

Don’t sow too early. Runner beans grow fast, and plants sown in early March can be leggy and pot-bound long before it’s safe to put them out. Late April is often better than late March in a cold spring.

Planting out

The dates here are for a typical lowland garden in England or Wales, with a last frost around 20 April. Plant out from early May to early June, after hardening the plants off for a week or so. Have fleece ready if a cold night is forecast in early May.

In Scotland, the north of England and frost pockets, wait until late May or early June. In the south-west, near the coast and in cities, early May is usually safe.

Sowing outdoors

From early May, once the soil has warmed, you can sow straight into the ground. Sow two beans at the foot of each cane, 5 cm deep, and remove the weaker seedling if both come up. Slugs love young beans, so check after rain.

Supports and spacing

Runner beans grow to about 2.5 metres, so they need a strong frame before you plant.

1. Push 2.4 m canes into the ground in two rows 60 cm apart, with canes 20 cm apart along each row.
2. Tie each pair together near the top, then lay a cane along the crossed tops and tie it in to make a ridge.
3. Plant or sow one bean at the foot of each cane.
4. Guide the first shoots onto the canes. After that they find their own way up.

A wigwam of six to eight canes tied at the top works well in a smaller space or a large pot. On windy sites, add a stake at each end of the row.

Runner beans need full sun and soil that holds moisture. Dig in plenty of compost or well-rotted manure in spring, or dig a trench in autumn and fill it with kitchen scraps.

Neighbours

Sweetcorn, squash and nasturtiums grow well near runner beans. Keep them away from onions, garlic, shallots and leeks. See our companion planting guide for more pairings.

Watering and picking

Runner beans take 70 to 90 days from sowing to the first pods and then crop for about ten weeks. Water generously once they start flowering, especially in dry spells. A mulch of compost around the base keeps the roots cool and damp.

Pick pods when they’re 15 to 20 cm long and still snap cleanly, before the beans inside start to swell. Pick every two or three days. Once beans ripen inside, the plant stops making flowers, and the harvest ends early. If you go away, ask someone to pick for you.

Common problems

Flowers but no beans. Dry roots and hot weather are the usual cause. Water deeply at the base. Self-fertile varieties tend to set more reliably in hot summers.

Slugs and snails. They eat young plants overnight. Plant out sturdy plants rather than small ones, and check after dark.

Blackfly. Clusters on shoot tips in early summer. Rub them off or blast them with water.

Frost damage. Blackened leaves after a cold night. Plants may regrow from the base, but it’s quicker to replace them with spare plants or a fresh sowing.

Look up the full sowing window on the runner bean page, and our last frost guide explains how to judge when it’s safe to plant out where you live.