Borders are puckering when I'm quilting them
 

Help! How do I prevent this! I'm doing straight lines with a walking foot. Is my presser foot too hard? Is there some magical trick? Did I not baste enough

How did you measure your borders? Did you just cut a long strip and sew it on, then cut off the rest? Or did you measure the center of the quilt and then cut the border to that measurement? Did you starch the fabric before cutting it? That will help prevent stretching.

If you didn't cut the border to match the quilt, sometimes this will happen. If you did measure it, did you pin it in place and avoid stretching the border?

Sometimes that happens to me when I've cropped the backing & batting before quilting. If that's the case, you could try fusing/gluing some batting to a 4" strip of fabric & stitch with a quarter inch seam to your backing fabric.

It could be the way you made the borders. Bonnie Hunter on quiltville.com has a excellent tutorial on putting on borders. I never have one pucker since I do it this way.

I do the same way! works for me.