"Two Knuckles of a Pinkie"
When I saw the flowers, I wondered if it meant the potatoes were ready to pick. Or did it mean we should deadhead the flowers and just let the plants keep growing? In the end, we decided to sacrifice one plant for the purpose of testing.
The exciting news is that we indeed have potatoes growing under there, and they look beautiful. They are, however, still very tiny. The largest one was no longer than "two knuckles of a pinkie" by Michael's calculation, which seemed like an appropriate measurement for a fingerling potato!
They still need more time to grow, but don't they look like they're off to a great start?