I have tried and failed so many times to re-grow green onions but finally found some success, and I want to share this tidbit with others. I tried half a dozen times to re-grow green onions but they always rotted. I tried different containers – same result. On a whim I put the one inch bottom stem pieces that I had cut off the long green onions into a vintage glass floral frog and this kept the onion stems from rotting, like they had so many times before. I have to change the water out every couple of days, but I just use tap water and that has worked out fine so far. Just so you get a better idea of what a vintage floral frog looks like – click here. I have no association with that page, I’m just including the link so people can get a better idea of what floral frogs look like. Hope this helps somebody!