My first attempt at growing something, I've planted three tubs with runner beans, they have flowered very well and are producing a good crop, but it appears that the leaves are turning yellow and what looks like premature dying, please is ther an answer.

You don't say how deep the tubs are, but one thing I do know about runner beans - they like a nice, deep trench filled with well rotted material and good soil to give the best results - in tubs, especially with the number of plants you have in them, you won't get such good results. That may well be why you've got this trouble. On the other hand, I'm not a veggie expert, my area's more decorative planting - I only know about runners cos I've actually grown them in the past.

Hi Jeffo. welcome to GOY . My runner beans have also gone a bit yellow this year and they are grown in pots, Alzheimer told me yesterday to give them a feed of tomorite, which iv'e done so you could try that.Other years they have been ok ,so it could be a bad year. good luckand don't give up.

I agree with Bamboo...beans of all things need a DEEP root run..and a lot of rich compost - and I suspect that despite your good feeding schedule - they are just struggling to cope as there are too many of them per tub.
Is it just the lower leaves that are affected...and if you are getting a decent crop - just enjoy it. If you want to - you could top dress the tubs with more good compost - but this late in the season it might not make a lot of difference now. In future years- if you have to grow them in tubs - just make sure they are deeper ones!! In the meantime - enjoy your beans!!

Sorry about that jeffo I missed the bit about you already feeding them ,must be my age !