This little trick seriously never gets old with me. Whenever I buy scallions from the supermarket, I re-grow them at least once. Re-growing scallions is so easy. I've done it in soil here and here. I usually can only get it to re-grow properly for me once in water, but if you plant these, you can cut off the tops and have them continue to regrow throughout season. If you have kids, it's a fun experiment for them to try. I have to try to regrow ginger one day, I heard that is pretty fun and easy too!