I don't know if this is common to do, but if not, here's a hint. When I buy green onions and use them in a recipe or whatnot, I plant the bulb end with the little tiny roots in some potting soil in a pot and put it on my kitchen counter. They grow up again and again and we can use them for more things. This seems to work several times, and it's an added bonus to have something growing in the kitchen this time of year.