I stumbled across this info online and thought I would share. "Scallions" or green onions are well known, but one thing I didn't realize is that they are typically the thinned plants from operations where they are growing yellow or white onions. Also, they are amazingly resilient and you can definitely plant them in your garden to grow into full size onions.
In addition, there is no need to leave the greens on when you go to plant. My grocer has them for 74 cents for a bunch of five. Knowing that I could use the greens I went looking for a way to use them and settled on making scallion pesto! It's exactly the same as basil pesto (pine nuts, garlic, olive oil, and parma) with the scallion standing in for the basil.
Sure enough, after 24 hours in the ground the shoots are already jumping:
You can also just plant them and use them for perpetual scallions whenever you need them. I am actually going for the full size onions.