Has anyone had much success with sweet potatoes? I've tried growing them two years on the trot, in a relatively warm part of the country, and have followed all the information I could find about the conditions that they like. However, despite this, the tubers that I get are rarely much bigger than my thumb. They still taste lovely, but it would be nice to get something approaching a bit more of a standard sweet potato size, as otherwise it's a lot of time for not much return. I am debating just growing something else next year and sticking to getting my sweet potatoes from the greengrocer. What are people's experiences? And have people found any tricks or tips that have reversed experiences like mine? Thanks.