I made a Halloween table runner, not my first, and it is super wavy! I've never had this happen. Does anyone know what I did incorrectly? I know the back is pieced and I had difficulty sandwiching it so it was tight. Thank you, any comments appreciated.

Try putting heavy books or dishes on it for a day or two. Dishes - glass 13 x 9 dish for cooking/baking.

When that happened to one of mine, the quilt shop owner lady told me to lightly spray some water on it (the edges) and lay it out flat and let it dry and that did help.

because of the way it's pieced, the edges are on the bias. looks like they got stretched a bit,

Thank you for all your suggestions! I will try the water trick and placing something on it.

it's really pretty. I would put something heavy on it. I use my DH's programming books.

Very pretty

Looks great, anyway! I just bought a quilting magazine and that same pattern is in it :-D

All of the above! To help avoid it next time, starch your fabrics before you cut. That will help when working with bias.

It's cute!

Did you use a walking foot to apply the binding? Did you cut the binding on the bias? I had this type of problem in the early/learning days of quilting. I suggest you remove the binding, press with steam, and then use a long straight edge/ruler to check the longer edges. Once edges are straight, cut your binding on the crosswise, press carefully, and apply with the walking foot. Good luck!