I've checked the books but still not sure. Is it cos of soil ph - I have clay soil ? Same happened last year so dosed with seaweed, lots of beans but the plants looked unhappy. I want happy plants :)
Had yellowing leaves on bean plants one year. I'd planted them in an area where either I'd had a bonfire or scattered loads of wood ash, and understand that because the ash is quite strongly alkali, it had the effect of locking up some of the nutrients in the soil and so the bean plants were suffering from a severe nutrient deficiency. You'd get a similar effect in any very alkaline soil, so maybe this is it? Liming might do this as well I would imagine, if the soil doesn't need lime.
mulched ours with grass clippings and got the same effect, they're growing strongly now, must've grown out of it :)
Give em a dose of epsom salts when you next water
thanks all - will try the epsom salts :)
A year or so ago I had yellowing and someone told me to use a weak tomato feed solution which I did and the plants turned green again.