It been 6 week, and my potatoes are still going like weed.  I have hilled them about 16 inches in boxes and know they are over  a foot tall again.  Is their a problem if i keep hilling them.  Wood for boxes is free, chick poo is free and top soil at walmart couple of bucks.  the plants keep getting flower on top.  How do i know if I am truely growing potatoes?