My husband’s science experiment

Somewhere AJ heard that he could grow green onions in a jar with water.  For the past month we have had this weird experiment happening on our kitchen windowsill.  He thinks they are growing, but I think they are the same.  The onions are beginning to look creepy and gross, a little bit Alien.  At what point can I throw this experiment out?  Or do I need him to come to his own scientific conclusion that the experiment is dead?  Any hypothesis of your own?