Once you cut off all your onions then leave your bottom tied together and put it in some water. I used a small dipping sized tupperware container and placed it on a windowsill to get sunlight everyday.
See how much it's grown? That was overnight. This is a very fast process. You'll have more green onions than you know what to do with after buying just one bunch of green onions!
This is about two days of growing green onions. Aren't they pretty fresh and green? I love it!
And here's the good news if you get too many green onions on your hands: you can freeze them! Either fill a water bottle in your freezer door or a small baggie. Then pull them out whenever you want to use some. With just the one bunch of green onions you can fill up for a whole winter without your fresh green onions!
Here's a tip: once or twice a week I would dump out the water and put clean water in. It will get murky.
Enjoy your endless supply of green onions!