I planted seed potatoes in sacks back in April but I can't remember what variety. They are like triffids now with abundant leaf growth and some with flowers on. When do you think it's safe to pull them out as I don't want to do it too soon
earlys will be ready now. maincrop won't
Have they flowered yet? If they haven't flowered it is unlikely they will be ready. The only method is to have a gentle feel around the outside of the bags to see if you can feel the potatoes.
They have a few flowers so I will leave them a bit longer
As long as they don't get blight or show other signs of disease, you can leave them until the leaves go yellow and start to die back i.e. treat them as a maincrop which, if they are just flowering now, they most likely are.