Best time to harvest potatoes

InTheMoorlands

This is my second year of growing potatoes in tubs and has been somewhat more successful than last year.  Sometime around August (just before the heatwave) I planted 10 Maris Peer seed potatoes in four tubs.  All the potato tops have now collapsed, although they are still greenish.  I intend leaving them until they have gone yellow or died off but wondered how long I could leave it before I extract the potatoes from the tubs.  Ideally, I would like to spread this over a few weeks until, say December, but wonder if this would be wise.  Would there be much difference to the crop if I harvested them today or in say four weeks?

Hostafan1

you risk them being attacked by slugs

Dovefromabove

The crop would not be improved by leaving them in the soil.  Take them out, dry them off, store them in a cool dark place.  

Busy-Lizzie

I leave Charlotte potatoes in the ground until December, so I would have thought that leaving them in the tubs would be fine. They are in a cool dark place. I wouldn't water them, maybe cover the tubs to keep the rain out.