On 07/08/2017 17:28, Paul Luton wrote:
After producing the usual green beans for a month my climbing french
beans are now forming with purple stripes. Could they be reverting to
one of the varieties used in producing the F1 hybrid ?

The poor devils are probably cold.
Quite a few veg carry a red/purple tinge when they get lower temps.
This evening I could actually see my breath when I was out picking peas.
David@a rain free side of Swansea Bay