Low temperatures & runner beans

[Primrose]

Can anybody tell me what's the lowest night temperature below which runner beans stop growing and start to shrivel? I keep thinking those still developing on the vine will not grow to picking point because of the cold nights but I'm still harvesting some at the moment.

[Colin Miles]

In my experience they will keep growing until the frosts stop them. Not very fast and if we get winds as promised they won't like that. At the moment mine have quite a lot of bunches which I probably won't develop properly because of the winds and low temperatures, but I keep on hoping. Have had them up to the middle of November before.

[Beryl]

I agree with Colin. I usually find this time of the year they like the cooler temperatures and seem to get their second 'wind' and produce a good crop at least untill the end of October.
They are perennial plants really and I have experimented in the past and cut the vines down leaving roots in the ground over winter and they have grown again the following year. Not a fantastic crop but they will.

Beryl.

[Primrose]

Beryl - that's an interesting comment. I normally cut my vines down after they've finished cropping and leave the roots in as generally advised for the nitrogen but in all the years I've been growing climbing beans (both Runner & French) I've never had them regenerate the following spring. Has anybody else had a similar success doing this?

Would you have to thoroughly cover them with a mound of earth to protect the roots from frost and low temperatures?

[Beryl]

Primrose,
I just gave them their usual generous layer of rotted compost. I suppose about 6" deep.

I can't remember what sort of winter we had but I imagine the usual mix of frost, snow, rain etc.

Beryl.

[PLUMPUDDING]

Three years ago I found a 15 ft bean plant that had grown from the roots I had left in the previous year, growing through my potato bed, but when I've tried to get them through the winter by potting the root up and over wintering it in the frost free greenhouse, nothing has grown, so it is a bit hit and miss. I think the keen, prolonged frosts we've had the past two winters would finish them off even with a good mulch.

[Johnboy]

Hi Plumpudding,
It is my observation that the more modern runner bean varieties do not make the bulbous roots of varieties of yesteryear. The first runner beans that I sowed ended up with quite large bulbous roots and would regrow is left in situ over winter. Over the last forty years I cannot really remember runner beans acting in the same manner with only the occasional large root. Some time back now I did an experiment with half a dozen bulbous roots and although they grew they put out very many shoots from the base but they never really gave me very many beans. I put it down to an experiment not worth pursuing again. I think it is far better to save some of your own seed and the plants resulting are then more vibrant and crop well.
An interesting topic never the less.
JB.

[Beryl]

I have to agree with JB. I did only do it as an experitment along side my usual crop. Unless you have the space to do it not really worth the bother. We do expect such a bountiful crop from our runners don't we?

Beryl.

[Nature's Babe]

I agree with Johnboy, one year my runners grew huge bulbous roots I couldn't remember the variety though, other varieties form much less. So easy to save seeds and heritage varieties breed true. I have saved my wisley magic this year agan.

[Johnboy]

Hi NB,
Just as an aside I picked a Wisley Magic bean the other day that had been missed in previous pickings and was just under 18" long and to my surprise it was perfectly edible without the slightest trace of stringiness. They are a truly wonderful variety and really well worth growing.
JB.