Potatoes in a bucket

My seed potatoes have grown so well in the bucket. They have reached to the top of the bucket and now theoretically they should shoot vines out within the bucket to make potatoes. I hope it works, but so far so good. Looking back what I should have done is add soil to the the vines as they grew each step of the way. for some reason Only one vine grew this tall and the others are slowly coming up. I had to bury the other ones so that I can save this one. Hopefully her buddies can catch up and shoot out the top of the bucket. If I can produce potatoes this year I'm going to be ecstatic.