If you plant a fully mature green onion, can you actually grow more onions?

Question

Ok, so my mom put an old onion in a plastic bag, and sealed it, and put it in the fridge. After a few weeks, we checked on it, and it actually grew scallions!!!!!

So she's wondering: If we actually plant a whole green onion (in soil, not a plastic bag), will it actually cause it to grow more onions?

Answer 1

yes it will spread good luck!

Answer 2

If it went to seed, you could plant the seeds and get LOADS of onions, but it wouldn't be the most efficient way.