Judith in England wrote:

Any runner bean growers will appreciate how quickly they do grow.

Yes! Not to mention how quickly the beans (pods) grow following rain.

[...]

The system only comes on for half an hour each day - so much so that the
water runs through the raised bed in to a soakaway. The system works
perfectly (in spite of the doubting Thomases when I was setting it up).

Were the Thomases here? I wonder on what basis anyone would think it
wouldn't work.

I was gobsmacked to find that on average they grew between 2.0 and 2.5 cms
every twenty four hours.

Yes, this doesn't surprise me at all. The do grow amazingly fast once
they get away, especially in spring.

The moral of the story - use soaker hoses on a timer (and don't forget to
"over-water" and have a soakaway ;-)

This is the only part I don't really understand - the need for a
soakaway (unless you are on otherwise incredibly boggy ground even in
the summer) and the need to over-water. If you think you're
over-watering and it is draining away from the beans, why not simply
reduce the time to 20 mins or every other day or something?

I make do hand watering with rainwater and plenty of organic matter and
mulch. Much more on-going effort, but also works.

Peter