Our family uses scallions from the grocery, but sometimes not all of the bunch is used before they are past their prime. Not rotten, but often yellowed instead of green, and sometimes developing odd curves. I think of these as "zombie scallions" because they aren't dead, but getting close.
I was getting ready to toss some of these into the compost heap with the coffee grounds and fruit peels, when I noticed some were sprouting roots. Instead of tossing them, I took them to a corner of one of the garden beds, poked a few holes in the ground with an old tire iron, and put a zombie scallion in each hole. After a couple weeks, they are growing again (the growing dead!
). I put another few in the same garden bed last night. They are spindly because they are shaded now by larger summer-season plants, but I expect the scallions will grow better once frost hits the summer vegetables and I cut those summer plants out. I am hoping to harvest them from time to time during the winter and spring.