why aren't my scarlet runner beans setting beans?

Jun 21, 2026 04:52:07

This happened last year also...they finally made some beans later in the summer.

This year they've been blooming for a long time and still no beans.

This is localized seed grown by a friend for years, he's gone now so we are unable to ask him questions about his beans.

Those I've shared scarlet runner beans with have a similar experience where they bloom for weeks without setting beans...then bear some late.

Our green beans are producing well and my long beans are setting beans.

I also don't see any pollinators on the scarlets and I thought those bright blooms would attract everybody.

attached photo from a month ago....now they are up over the trellis and have been blooming steadily since then.

Jun 21, 2026 05:01:55

Try misting them with water every evening. Disclaimer, I haven't actually looked into this properly, so take it with a pinch of salt, but the theory is that they are from a misty/foggy region, so I've always been told that they need it. Maybe they just need a little more moisture at the roots, so spraying them with a hose does that. Or maybe the first few never set. I grow them nearly every year, and in my experience, the first few flowers never set, but by the end of the season they are hugely productive.

I'm keen to see if anyone has good tips on getting them to start setting sooner.

Jun 21, 2026 05:03:11

found a good explanation written by Joseph Lofthouse in this thread https://permies.com/t/53665/Growing-runner-beans-Portugal#439651

I might add a shade cloth to my trellis....

I thought the beans might already be adapted to this area since our friend grew them in similar conditions but he might have been able to plant earlier and in a semi shaded location.

Jun 21, 2026 05:10:05

thanks Ali!

I could try that with a watering can...thanks.
We've had more rain than usual for june but it's also been very hot.

Jun 21, 2026 08:35:33

I thought I would add a shade cloth but beans are already at the top and there's no space without damaging vines.
I planted both scarlet runner and hyacinth beans thinking they would be cool all blooming together but of course the hyacinth is only just budding.

Maybe the overhead vines will shade the rest well enough to help germination.

I'm still surprised at the lack of pollinators there compared to elsewhere in the gardens.

The darker leaves in the photos are hyacinth beans.

Jun 21, 2026 09:03:51

Yeah the heat thing is real with runner beans. Mine did the same a couple summers ago, weeks of flowers and nothing setting, then as soon as we got a cooler spell they went mad. The misting idea is worth a go too, I've heard that before about them needing more humidity around the flowers to set properly.

Jun 21, 2026 09:48:05

Pre war advise was to spray or toss water over the vines generously with cold water in the heat of the day to attract pollinators and cool the plants down to help the beans set.

In a heat wave, I'll do it in the morning after chores and again after lunch so I can accidentally get wet and cool off because running around like a kid under a sprinkler looks a bit odd at my age, but watering my beans, that's socially acceptable.

It also helps prevent the weird inner skin that forums in the heat.

Soil too acidity is the next thing to test for.

Jun 21, 2026 11:24:30

I guess this is why I always considered Scarlet Runner Beans to be a cool weather plant.

Jun 21, 2026 11:28:47

I remember some wartime guides recommending both french (normal green beans) beans and runner as the runners produce at the start and end of the season and french beans produce in the heat of the summer. If the summer is too hot or too cold, we can still get a harvest of one type or t'other.

Jun 21, 2026 12:47:52

thanks everyone!

I did plant them as early as possible here....and we've had a 'relitively' cool and wet spring.

I think what I consider cool weather is not the cool weather needed for these beans?

I know that most of our green beans won't set beans above 95F and that cow peas and long beans don't seem to mind the heat.

Apparently scarlets need maybe 60F to 70F tops?

Other than for those striking red blooms I'm not sure they are worth the space here if they are that finicky....not a perinniel here either.

Jun 21, 2026 14:27:11

Despite them being a traditional British garden staple, I've given up on them for the same reason. I think our summers have gotten too hot. Thankfully I can still grow French beans.

Jun 21, 2026 14:34:10

I grow both types for that same reason. Normally, french beans win, but this year, total crop failure. Scarlet runners are growing and setting beans like stink. I've never had a year where both fail (but a few years where both bumper crop), so if there is room, both get a spot in the garden. Besides, they make great shade for the late summer chard.

Jun 21, 2026 14:58:21

Our summers are predictably hot and dry...and sometimes march, april and may are in the 90F's...and september and october the same...and dry.

I think I'll go back to spotting in a plant here and there for a bit of color and stick with our hot weather beans.

This year is wetter, otherwise I doubt they would be growing like they are.

I love the idea of using their shade for chard though...and maybe my struggling arugula?

....our friend was growing them here for years...this is his seed so it must be possible and I just have the timing off.

We do as you describe R. but it's between green beans and more heat tolerent long beans and cow peas.
Too hot too early for english peas even.

Jun 22, 2026 06:40:32

Judith Browning wrote:
I think what I consider cool weather is not the cool weather needed for these beans?
I know that most of our green beans won't set beans above 95F and that cow peas and long beans don't seem to mind the heat.
Apparently scarlets need maybe 60F to 70F tops?
Other than for those striking red blooms I'm not sure they are worth the space here if they are that finicky....not a perinniel here either.

for me (9b) scarlet runners and christmas favas are winter crops. I would let yours stay in as late as possible into the fall as possible even after the others are done. your hyacinth beans will like as much heat as you give them, but at the first sign of cool nights will begin to look like they're done-- and then your scarlet runners may start looking a lot happier in comparison!
(I stopped trying to grow them, as unseasonably warm falls meant that they just struggled until eventually it was too late. They're beautiful but I have limits)

Jun 27, 2026 09:33:51

....after much searching I found three 1" tiny beans!
They must have set during a few days cool spell we had a couple weeks ago?

Jul 01, 2026 21:33:09

I can't grow scarlet runner beans. . . too hot - dries the pollen - too windy - dries the pollen. I've been sticking with the bush bean types since it's easier to hide them from both the sun and the wind.

The barrel was packed to the top with fish. And he was shooting the fish. This tiny ad stopped him:

Come Visit Wheaton Labs!

https://permies.com/wiki/367505/Visit-Wheaton-Labs

Better Wood Heat DIY Rocket Mass Heater DVD