Originally Posted by
bradleycpa
Thanks for the info. By bunching, I mean that the bottom has extra fabric between the rows of quilting. the top is nice and smooth, but the bottom isn't.
So, your backing fabric has gathers, I take it? This would be caused by not keeping the backing fabric taut and smooth as you're quilting. You might want to check it every time you advance the quilt, get a mirror or crawl underneath to look and make sure everything is smooth and not loose before you resume quilting.
Of course, I'm assuming you were using cotton and not something stretchy, such as Minkee.