I have seen several times on Pintrest that you can regrow some of your veggies from the grocery store. You most certainly can. I did this with my green onions and my romaine hearts.
I have had this vase for years and finally found something to use it for. You can see where the white of the onion stops and the regrowth starts. The onions are about as big as they were when I bout them a little over a week ago. All that is in there is water and beads. We will be putting some miracle grow in there soon just so the plants have some food.
You can see where these were cut off too. This is how tall they grow in a week and it is just barely enough to have on taco night each week. I am looking forward to spring finally settling in so I can grow my favorite french blend of lettuces. Till then, this is a great way to get in some lettuce without having to pick it up every week.