We did this last year using old supermarket potatoes we found in the back of the cupboard, and on Christmas Eve we harvested a very small number of potatoes, this was still more than I expected. This year we have got proper seed potatoes of an “unknown variety” but I am told these have been kept in cold store until now and they should be ideal for a Christmas crop. I must say, they all came through the post individually wrapped in newspaper, very smart. I put these in the same bags as we had our potatoes earlier on in the year and here they will sit until the weather gets colder, at which point I may look into a more sheltered spot.
Growing potatoes at this time of the year allows them to take advantage in their early days of our hot weather so that by the time the cold darker days come they are already up and running. These will need plenty of watering if they are to get that head start. The potatoes can then stay in the ground even after the first frosts and the plant on top has died.