Runner Beans good and bad

[Marb67]

I have a very healthy, vigorous runner bean plant that is producing well. What I am finding though are good beans and thin, whispy sickly looking ones. Is this normal ? I feed with comfry and always water well. It is in a large container and some of the plants came back from last year.

[veggiechicken]

The thin sickly ones have probably not been pollinated.

[bearded bloke]

Have you got a picture of the "whispy sickly looking ones" please,how long do they get ?

[Marb67]

About 2-3 inches and a yellowy green.

[Hazel at the Hill]

Yes, I get some of those too, Marb - I don't know what it is (but would guess that VC is right about pollination), but I have plenty of good 'uns so I don't worry about it.

[Potstubsdustbins]

Yep same here, it happens every year. I just take them of and throw them in the compost bin and there is always plenty left.

[Big Gee]

If the flowers have set (small runner bean pods appear) then pollination has taken place. If there was no pollination the blossom would drop and no bean pod at all would be produced.

Suspected causes could be cold weather or an over rich nitrogen soil and a deficiency in Potash. If you're feeding heavily with comfrey then you will be feeding masses of nitrogen. This produces greenery but if the potash level is low then the pods (fruit) could be stinted.

[Marb67]

It isnt nitrogen in comfrey, it is potash.

[Potstubsdustbins]

^^^^^^^^^^^^^^ Correct Marb typical values are N 0.014, P 0.0059 and K 0.0340

[Big Gee]

As you all probably already know, comfrey’s deep roots work to bring nutrients up from the subsoil. These nutrients are then made available in the abundant number of leaves it produces every year (4-5 lbs of leaves per established plant per year). The leaves are rich in nitrogen AND potassium with a decent amount of phosphorus as well.

The leaves have an average NPK ratio of 1.80 - 0.50 - 5.30.

The soil could still be potash 'poor' even though there are high levels of potash in the comfrey fertilizer applied. Comfrey is ALSO considered to be nitrogen 'rich'. Over rich nitrogen soil CAN cause runner beans to develop smaller than usual pods with an exaggerated green leaf development.

Sorry if I caused some confusion with my bad grammar and lack of clarity!

[Knight of Albion]

I'm very glad to hear that you've had success with your runner beans, dear Marb. Good on you.
We're coming to the end of the season now, diminshing hours of sunlight and getting chillier at night (a frost in Northern Ireland and parts of Yorkshire the other night) so some beans are going to fail and others are going to get tough, too tough to eat. But perservere, you should still get a few for the pot and the rest you can let run to seed, to gather for next year.

[Greenleaves]

Hi Marb, Comfrey is also high in nitrogen. Have you considered trying self fertile varieties? I find Firestorm a great runner to grow. I dont fuss with preparing a trench as I find it makes absolutely no difference

[Kristen]

Comfrey is also high in nitrogen

I think that depends on your reference point?

Relative to Potash then Comfrey has relatively little Nitrogen ... compared to Cow Manure, weight for weight, it has more.

I prefer to think of fertilisers as the relative values they have of N, P and K rather than the absolute amounts - the absolute amounts are a guide to how much/little needs to be applied, but to me they don't help with whether a particular fertiliser is predominantly Nitrogen or Phosphate or Potassium

But maybe I misunderstood your point?

[Alison]

Hi Marb, Comfrey is also high in nitrogen. Have you considered trying self fertile varieties? I find Firestorm a great runner to grow. I dont fuss with preparing a trench as I find it makes absolutely no difference

I find putting something under my beans really helps but it may depend on soil type. I usually dig a good sized hokey under where each wigwam will go, line with cardboard then normally add a load of Bokashi mix and comfrey leaves before back filling. Keeps the moisture in too.

[Big Gee]

The biggest advantage of filling a trench under a runner bean row is to provide a layer of moisture retention, rather than providing nourishment (assuming the soil is relatively fertile - if it isn't well a layer containing a higher proportion of nutrients - like comfrey - will obviously also be a bonus)). That is why a burried layer of just newspaper will enhance the environment the runners grow in because a thick newspaper layer will provide a resorvoir of dampness that the runner bean roots can tap into.