My husband is an interesting guy...when he makes enchiladas or other things that he uses scallions or green onions in, he doesn't use the white part, just the tops. Soooo...he decided, rather than let them go to waste, he'd stick them in the ground.
Ah ha, indeed they DID grow new tops...outdoors.
Winter came, and we decided we were fond of those fresh, always-ready scallions, so we put them in a pot indoors, in the kitchen.
....and that worked, too. Recently, our CSA, Fresh Connect, offered organic green onions, so of course we got them. And now we have too many onions for the pot above! We got a long, rectangular, terra cotta pot, and now we REALLY have an onion farm.
We cut them back whenever we need a bit of garnish...and so far, we've never run out of green onions, free and fresh. Doesn't get much better than that.