I read something somewhere sometime back:
After you cut the last 1/4″ off the base of a grocery store scallions, if you plant this nub with its root remnants directly into the soil, it will regenerate.
So I did…
And it did…
Seriously, these were in an area adjacent to some onion sets last year and I became frustrated when they failed to bulb. Eventually (after the green leaves stayed healthy and green for the entire summer) I remembered that these were my scallion nubs.
So I ate a few and then divided most of the rest last fall to allow for another multiplying cycle; each one becomes a cluster of 3-5 (as in the first picture below) after being given a little room and some time. Also, the individual onion stalks are larger in diameter than I recall the originals being. Note that these are very slow growing, maybe a little more than a full year to reach the current size.
Conclusion: Not bad for a low expectation/almost forgotten experiment.