I grow green onions inside on my den window sill in the winter. I simply started with the root end of a few pieces and put them into potting soil. They grow up like no one's business and the strange part to me...the non green thumber...is that I am now on harvest #6 from the same original onions. I also grow grape tomatoes from one grape tomato slice.
I don't really get a lot...but I like doing it.
Life without onions does not bear consideration.