The potato grow bags with the flaps near the bottom worked for me.
Potatoes are an extension of the stems of potatoe plants so this encourages stem growth.
Similar to what we do to encourage long roots on tomatoes.
The flaps on the bags allow you to reach in and take early ones.
I intend on keeping a bag of potting soil beside the potato bag---that way I'll remember to keep adding soil.
It works for us who are too lazy to "hill" them up.
