When I lived in the city, I often resorted to unique answers to my gardening problems, and one of those was to grow my green onion tips back.  I would regrow them in water in the sun and then plant them in dirt that I supplemented with pinecones. Pinecones don’t ordinarily resprout unless exposed to heat, but apparently there is a chemical reaction which induces them to sprout, because my onions always grew little baby trees.

Then I would cut the tops off of the onions and let them get fat and then start it all over again.