It’s true. You can regrow shallots in a glass of water. Here’s the results of a couple of days, actually it could be a week or more as I forget when I actually ‘planted’ this bunch. Since then I have simply been changing the water each day. You can see where they were cut and the fresh green regrowth.
I only recently read about this technique on a number of websites and thought that I would try it out for myself. As you can see, the results speak for themselves. If you already have a vegetable garden planted, or a spare pot lying around, plant them in the soil and apparently they’ll grow back indefinitely (ApartmentTherapy).