Ribbing for waistband?

I'm making N a whole stack of these shorts for kindy from some french terry sweatshirting that I had in my stash. I've got ribbing that matches the terry and I'm wondering if it might work to make the waistband from that. Would I still need to put some elastic in the waistband? I can just do a trial run and see what happens but I thought I would ask the question first just in case anyone has already done that using this pattern. The terry has almost no stretch to it if that makes any difference.