Did you know that grocery store green onions will grow back the part you ate? Neither did I until about a week ago!
In the picture below you see the white part at the bottom of a set of grocery store green onions. I cooked a delicious recipe for Christmas dinner and ate the tops. I planted the roots in a pot under my grow lights.
After only 4 days, the greens were already growing back (below).
The picture is a bit blurry, but you get the idea. Already the tops were growing back about a centimeter on most of the onion root ends.
Update: late February…
I harvested the greens again after 6 or 8 weeks. The bottom white part of the onion had grown weary. It was thin and lifeless and I knew they wouldn’t grow much for me if I tried them again. Some were barely hanging onto the soil and most hadn’t grown any new root length that wasn’t there already . I’m not sure if it was a need for fertilizer or a need for better lighting, or if this is just a trick that works once per set of onions. I chopped and dried mine and put them in a glass jar to use later in soup.