Update: Growing Potatoes in Straw

Remember our attempt to save space and grow potatoes in straw?
The Magician decided that the green tendrils coming out from the sides were starting to wilt and it was time to harvest our potatoes.
What followed is best depicted in pictures:

Oddly enough, the (now rotten) potatoes that were the original seeds, the tendrils with the leaves, and the tiny potatoes were not even adjacent to each other in the straw.  I thought that was weird.
I thought the potatoes would be nasty, but they actually tasted just fine.  The straw went into the compost pile.
Would it have worked if the pile had gotten more water?  Could we have left the potatoes in longer and had them get bigger?  Is this the strangest use ever of an unwanted laundry hamper? 
I'm calling this experiment inconclusive.