In message , Nick Maclaren
writes

In article , "shazzbat"
writes:
|
| "compo" wrote in message
| ...
| Runner beans do not grow very well in the far north of scotland so this
| year I decided to try growing them in the polytunnel. The plants are
| growing very well, in fact I'm not sure whether I should pinch out the
| tops to stop them over-growing. My main problem is that the flowers are
| not setting any beans. How do I ensure pollination?
|
| It would seem that by growing them in the tunnel you have separated them
| from their pollinating insects. Can you open the tunnel up on fine days?
| Alternatively, next year I would work out a removable covering to allow
| pollination. Maybe a frame that can be fleeced over, something like that.

Possibly. A more common cause is too little water or too dry an
atmosphere. They like reasonably high humidity and plenty of
water at the roots (but not waterlogging).

I had that problem last year. Lots and lots of flowers but no beans.
Solved by spraying the flowers with water in the late afternoon.

IME it is pretty hard to make a perfect polytunnel that keeps all
insects out - though most of the ones that get in spend their life
bouncing off the roof.

Regards,
--
Martin Brown