I had planted a variety of red onions from seed this past late spring. They were grown in compstable boxes above ground. As we have now had very cold nights and some frosts, I have taken the boxes inside. Most of the onions still have very health and strong green shoots. None of them developed any bulbs of significant size. I would describe them as similar in shape/size to shallots or green onions. As I have never grown onions from seed before, is there a way to over-winter them to see if they will come back next year (such as with garlic)? I know we can use them as is. If I plant in ground outside and give a good layer of mulch, would this work? Should I pull them and store in cool area indoors to replant next season? Any ideas would be appreciated.