Flowers fall and no pods set
Hot, dry weather and dry roots are the usual reasons. Water regularly once flowering starts, especially in pots. A mulch helps. Some modern varieties with French bean in the parentage cope better with hot summers.
UK crop guide
Runner beans
Runner beans are tender, thirsty, and one of the heaviest crops you can grow up a small bed. They will not survive a frost, and the seed will not germinate in cold soil.
The RHS puts indoor sowing from mid-April to May. Outdoor sowing waits until the soil has reached 12°C and frost is over, usually mid-May in the south and early June in the north.
- Sow indoors in April and May. From mid-April to May, one bean about 5cm deep in a small pot.
- Sow or plant outside in May and June. Outdoors from mid-May in the south and early June in the north. Indoor plants go out in late May or early June.
- Harvest in July, August and September. From around mid-summer, for eight weeks or more if you keep picking.
Sow indoors
From mid-April, sow one bean in the middle of a small deep pot, 5cm deep. Keep it above 12°C in a bright place. Indoor sowing is the better route in colder parts of the country, and it keeps the seedlings away from slugs.
Put the canes up before you sow or plant. A double row of 2.5m canes, 45 to 60cm between the rows and 15 to 30cm between canes, tied as an A-frame, is the usual support. A wigwam of five or more canes, 15 to 30cm apart at the base, fits a border or a large pot.
Sow or plant outdoors
Wait until frost is finished and the soil is at least 12°C. Sow two seeds 5cm deep at the base of each cane and thin to the stronger plant. Dwarf runner beans, which stay under about 45cm, are sown 30cm apart with 50cm between rows, and they need only short twiggy sticks.
A large container can be the final home. Climbing beans want a pot about 75cm wide and 45cm deep, heavy enough not to tip. Dwarf beans fit a 30 to 45cm pot.
Plant out
Plants raised indoors, or bought in a pot, go out from late May or early June, after hardening off. Plant one at the foot of each cane and tie it in loosely. Water well. A mulch of compost or well-rotted manure after planting holds moisture, which these plants need once they flower.
Spacing and depth
- Along the cane row
- 15 to 30cm between canes
- Between the pair of rows
- 45 to 60cm
- Depth
- 5cm
- Dwarf plants
- 30cm apart, rows 50cm apart
Harvest
Plants usually start cropping around mid-summer and will keep going for eight weeks or more. Pick pods young, about 20 to 25cm long, while they still snap and the beans inside are small. Every two or three days is not fussy, it is how you stop the plants shutting down. Once pods mature, flowering stops.
At the end, cut the tops off and compost them, but leave the roots in the ground. Beans fix nitrogen, and the RHS suggests leaving those roots to feed the bed.
Common problems
Slugs and blackfly
Seedlings are an easy meal for slugs. Indoor sowing avoids the worst of that. Black aphids can build up on the soft tips. Squash small clusters, and keep plants well watered so they grow through an attack.
Frost
A single frost kills them. Do not be tempted by a warm week in early May if your region's safe planting time is later. See the frost date page before you plant out.
What you'll need
Kit for this crop, based on the method above.
- Peat-free multi-purpose compost
For pots, modules and containers once seedlings need more body.
- Module trays or small pots
For crops started under cover. Deep pots suit peas, beans and sweetcorn.
- Canes or hazel poles
Runner beans need supports about 2.5m tall. Cordons of tomatoes need a cane or a string.
- Soft twine
For tying in tomatoes and beans without cutting the stem.
- Garden compost or well-rotted manure
Dug or mulched in before planting. Do not use fresh manure.
- Watering can with a rose
A fine rose avoids washing small seed out of the drill.
Common questions
Can I sow runner beans straight outside?
Yes, once frost has passed and the soil is at least 12°C. The RHS puts that at about mid-May in the south and early June in the north. Indoor sowing from mid-April gives an earlier and more reliable start.
Why have my runner beans stopped cropping?
A pod left to fatten tells the plant to stop flowering. Pick every couple of days while the pods are still tender. Dry soil at flowering time has the same effect.
On the calendar
Related crops
Sources
- RHS: How to grow runner beans. Checked 11 October 2026.