I decided to dig a trench for the potatoes this year. As it turned out, I had to dig two trenches--about 15" deep, 20 feet long, 7" or so wide. (I had a lot more seed potatoes than I thought.) I've been burying the greenery that sprouts up as I go . . . actually, it got socked pretty good two weeks ago by the first wave of the big thunderstorms that made it our way. But, I've been continuing to bury the green leaves that have been emerging from the ground. When should one stop? When the level of the trench meets the level of the ground around it? Or should I continue to bury the stuff, mounding the dirt up?