Q.When Rooting A Poinsettia, What If I Don’t Have A Rooting Hormone? Is There A Substitute Or Something Else I Can Use?
The piece in the glass is a piece that broke off about a week ago. I’ve never messed with poinsettias, this one belongs to My Lady Reeves. I wasn’t sure how to root it or if I could even. So, I just done what I would do with just about any plant. I put it in some moist potting soil and gave it just a little bit of water. It has been inside until yesterday.

Certified GKH Gardening Expert
There are quite a few options that you might have around the house, already! Aspirin is a good one that can act a little like willow water for helping the plant establish roots. Honey is another of my favorites, and you can mix it with a little cinnamon for added protection.
https://www.gardeningknowhow.com/garden-how-to/propagation/cuttings/natural-rooting-methods.htm