Runner Bean Pests and Problems

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 Updated 12/05/2017

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Runner beans are a great vegetable to grow thanks to the large harvest they can produce. Once the inital work of digging a trench and setting up supports has been done, it's just a case of watering them every day and waiting for nature to do its work. If you do encounter any problems though, have a look at the Q and A below for some help.

No beans being produced

I decided to fill the space left in my green house with runner bean plants. They have grown very well, look healthy and are flowering daily. But when the flower dies back it just drops off completely from the main stalk leaving no bean. They are watered daily and the greenhouse door is opened during the day for ventilation. I would be grateful for any advice.


This is not all that an uncommon problem. It is usually worse in hot and dry seasons, so it may be that your greenhouse is just too hot for the plants at the moment. You could try watering even more, mulching around the base of the plants to conserve what water you do give them, and opening all the ventilation in your greenhouse all of the time.

There is a chance that sparrows or bumblebees are actually destroying your flowers, but given that you are growing in a greenhouse I tend to think it is the extreme micro-climate which is causing your problems. If you want to grow beans in a greenhouse, a French climbing bean would probably be better; or you could try lots more moisture-retaining compost under the plants if you do the same with runner beans next year.

On the plus side you might just find that if you cut the runner bean down to the ground rather than pulling out the roots, and cover it with a thick straw mulch for the winter, it could come back next year - of course you might not want a runner that doesn't produce beans.

Not many beans

My runner beans this year have been splendid, lots of really healthy vigorous growth and the most flowers we have ever seen. Unfortunately very few of the flowers have become beans and although we have some beans its nothing like as many as we have had other years with about one tenth of the flowers.

The only different thing we did this year was to compost the bean site in January whereas before I am ashamed to say we left them pretty much alone. Apart from feeding once or twice with phostrogen, just the same as we have done other years. The flowers are just dropping.

Is it because they haven't been fertilized or is their something more sinister going on. We have seen quite a few wasps around the flowers this year.

Any advice would be appreciated.


Hi, if anything digging in compost should have helped your beans, and may be the reason why you have any beans at all. I guess - not knowing what your year has been like - that you have had a hot and dry time of it. Runner bean setting is always worse in such seasons.

Try to keep the plants better watered and don't forget that if even one bean on a plant reaches maturity that will be the end of flowering for that year. By the way, although sparrows and bumble bees are often implicated in the destruction of runner flowers, wasps are normally reckoned to be a gardener's allies until August.

Yellow plants

We have bush green beans (Blue Lake variety ) and they are growing extremely well, large bushes and plenty of blooms ... some are beginning to become beans and all seems well except that the plant leaves are beginning to turn yellow. The plants are all fading yellow evenly and it seems like a soil deficientcy. So far the beans are still developing. What should I do ? By the way, I live in texas and I have been watering every other day for an hour or so. Thank you , Jim


Hi, Since the yellowing is uniform and in the older leaves(?) and you are watering a lot a possible deficiency which springs to mind is nitrogen. This can leach out of the soil and the leaves will turn yellow. The other possibility is mildew which can occur if there is too much humidity. Have you thought of mulching and hand watering at the roots only? Is it possible that you are under or over watering? Look at the roots for any signs of rotting (over-watering) and make sure that the water is able to drain away ok. Stick your finger in the soil-it should be damp,not wet. Also have a really good look for any pests lurking in the soil,under the leaves or under any nearby dead leaves etc.

There are a few blights which can affect green beans but yours sound basically healthy. Also the beans sound as if they are ok which is an important point! I think that the first thing I would do is to make sure the watering is right and that there are no obvious pests.

Unseen pests

I have successfully grown four runner bean plants from seed and have planted them out into big pots with six foot canes. However, although they seem quite healthy and are growing the leaves have been eaten and I cannot see from what. Is there anything I can do to prevent further damage. The plants are still growing and have produced new shoots


Hi, The most likely suspects are slugs and snails. They will hide under pots and pot rims during the day and then come out to feast at night(especially when it is wet). To check out this theory have a really good look around the pots and the area around them. Look for places where the slugs and snails can hide. Little piles of leaves can shelter them. If there is any debris on the surface of the soil in the pots slugs and snails can hide under it. Slugs can also shelter just under the surface of the soil. If you find slugs and snails your best bet is slug traps, gravel around the pots and copper tape around the pots.

Pinching out

Hi, Do you pinch out growing tip at any time?


Pinch out the growing tips when the plant reaches the top of the canes.


We live in South Australia, hottest state in the hottest country they say. We are located in the Barossa Valley and were advised not to plant until all chance of frost is gone... end of october, we have had magnificent scarlett runner plants, but not one bean. we are told that it is too hot and the pollen dries prior to the bees arriving. MY QUERY is, how early can we plant?? Thank you in anticipation of a reply!
#28 - - 02/14/2018 - 02:59
I have been growing runner beans successfully for several years in the same spot ( against a SW facing wall, on canes ). However, in the last two years I have had no plants grow to maturity. With no sign of any pests ( aphids, slugs, snails etc. ) as soon as the plants grow to more than 15 cm. or so something is eating the leaves and particularly the top bud so that all I'm left with is a naked stem. This year I've even waited until the plants are 30/40 cm. high before planting out without any success. I've tried putting old BBQ ash at the foot of the plants in case it's slugs/snails but with no effect.
#27 - Andy Callaby - 06/03/2017 - 05:33
Should I pull up my runner beans, let them die back, or do something else. We are getting to the end of the season. They are still green and still producing, but our warm days are behind us. I am in Washington State.
#26 - Cyndi - 09/28/2016 - 19:18
Hi, is it possible to grow runner beans out of season in a greenhouse in England.
#25 - John - 08/30/2016 - 08:15
We grow runner beans in large ipots, about five plants in each pot. They have produced a good supply of beans until yesterday when we noticed that the leaves on one plant are showing signs of getting limp and some are turning yellow. The other pots which have been watered and fed in the same way as the other plants which still look healthy and producing. Could you let me know what I have done wrong please?
#24 - P.J.Whitehouse - 08/27/2016 - 03:56
Hello why does immature runner beans keep falling of the parent plant,there is plenty of growing leaves and flowers thanks for any advice you can give me Bernard Moran
#23 - Bernard Moran - 07/25/2016 - 10:07
Help ! We have planted peas and runner beans in pots in greenhouse and something is eating them some were right out of the pots and chewed the peas just had the pea skin on thetop of soil !!!is it mice
#22 - Jenny.ellis - 04/17/2016 - 06:02
i would like to know if it is best to plant two or three beans together or a single one for each cane
#21 - les - 08/10/2015 - 04:46
We have two problems that we need help with please
1 Tomatoes flower and flower stems dying but plant in good health
2 Runner bean are setting flowers but plants are not climbing up canes. They are 4ft 6ins high [Aug 2015]
Can anyone advise please.
#20 - mick j Langridge - 08/07/2015 - 03:57
Can you tell me what is eating my runner bean flowers
#19 - chris england - 07/04/2015 - 10:41
My runnerbeans have been wonderfull but now the foliage is covered in a black sooty powder --help please .
#18 - Colin Timms - 09/15/2014 - 05:24
Hi. Although we've had about 15 pounds + of Runner Beans, which is quite a good crop, when my husband planted them they came to nothing, he then planted a second lot of seeds. The thing is they all came up after all and because they are so close, there are SO MANY leaves I can hardly see to get in to pick the beans hiding at the back of the crop. There is a solid foot thick, wall of leaves - 2"-5" across. Will it hurt if I pick some off? The flowers and beans are getting no sun at all although they are in partial sun if it's kind enough to shine. Can anyone help please? Blanche.
#17 - Blanche Martin - 09/14/2014 - 10:04
same problem as Natalia to many leaves to see the beans. they have grown really well with loads of beans and flowers but I seem to have far to many leaves. need to know is it ok if I remove some nothing wrong with them,nice and green
#16 - lynne - 08/10/2014 - 10:50
I've planted 3 lots of seeds now & only 1 beans grown, ice wire netting over bed so it's not squirrel or mice, however 1 did grow for a week then I found it pulled up with the leaves & stem in tact but the seed pod & roots gone! Please help, any suggestions welcome. Liz
#15 - Liz probyn - 06/11/2014 - 14:34
Hi, i have a problem with my runner beans. They are flowering lovely, but the flowers are falling and the bees seem to be going round the back of the flower and piercing the back.
#14 - carla c crossland - 07/29/2013 - 07:52
hello.slugs or snails have been eating my runner beans and they have eaten the growing shoot,because the little leaves are more tender up there.Is there anything I can do to get the plants to grow a new growing shoot?Cheers.Simotec
#13 - simotec - 06/30/2012 - 07:02
i planted 5 runner bean plants growing up a trellis everthing is growing well until 3 days ago the stem on one plant was snapped from the point were it comes out of the soil,today checked the remaing 4 plants all the stems have been snapped or eaten,dont have any cats ,dogs in the area anyone had anything similar happen to them
#12 - k irwin - 07/11/2011 - 14:54
I raised my runner beans from seed. I planted out 3 days ago in sandy soil. Today several are reduced to stalks. Is this birds? It's not rabbits as I,m fenced in. Please help before I loose them all.
#11 - carole - 05/17/2011 - 12:54
Hi, I live in the south of Spain. It is very hot here during the summer months so I thought i would plant some beans last month so they would be flowering in the cooler winter months. They are now about a foot high and are already flowering.. I am assuming the flowers wont set as its still very hot and very sunny. The plants and leaves look a healthy green colour. What has gone wrong?
#10 - Rod - 09/22/2010 - 10:46
My Runner beans have been growing very well, flowered and now the buds have started to form. I appear to have somthing nipping away at the buds any suggestions ??? there are no signs of slugs
#9 - Julie Taylor - 07/23/2010 - 10:55
My runner beans look very healthy but the beans themselves are bulbous at one end and thin at the other - what am I doing wrong
#8 - john thorn - 07/11/2010 - 04:55
We are first-timers for runner beans and they are looking good but I have just noticed an infestation of black insects mainly on the underside of the leaves. We are organic growers and wish to find an organic way of resolving. We have been told that soapy water will do but is this really an organic way to resolve as soaps presumably have chemicals that could be absorbed?
#7 - Linda P - 07/07/2010 - 06:21
hi, please help, i am growing runners for the first time and have done them from seeds. Looking very good so far, lots of flowers, however i have so many leaves, almost blocking the flowers. Will it damage the plant if i remove some leaves?? Also was gutted to see that some flowers have dropped off with the bud. I water them daily and have them outside. Many thanks :)
#6 - natalia - 07/01/2010 - 02:03
My runner-beans are growing just the stalks
and no leaves,as if something has chewn them
off in the ground.Can you offer some advice
#5 - Paula Tapp - 06/16/2010 - 01:25
my runners are being decimated by something! The new shoots are nipped off and can be seen lying on the ground. There are also shredded leaf parts on the ground, which I guess would suggest pigeons? Any thoughts? Luckily plants are still producing new shoots.
#4 - richard tofts - 06/13/2010 - 04:26

my green beans havealot of holes in them could u tell me if there is anything eating them they out in the garden not in a green house. and what should i do.

thank you
#3 - jacqui - 06/11/2010 - 17:29
My Runner beans have started well and are just coming into flower, watered regularly, the leaves have suddenly wilted, not dis-coloured at all. I have been growing them for years with no problem. They are from my own crop last year.
#2 - Linda - 06/10/2010 - 08:40
I am a first time grower of Runner Beans and although they are growing (very slowly it seams) the leaves are fading to yellow. Is this normal for beans? Should I be feeding them with anything?
#1 - Sarah - 05/30/2010 - 09:01
The soil/compost in 15" tubs looks OK from last year -even underneath (for my ENORMA runner beans OK to use again?
#0 - David Keightley - 05/30/2010 - 05:29
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