In Sharon Schambers' excellent video tutorial about hand-basting a quilt (http://www.youtube.com/watch?v=bhwNylePFAA) she stresses the importance of making sure you have several inches all the way around of batting and backing, but never really shares WHY this is important.

While I do follow her basting instructions, and have been VERY pleased with the improvement in the final product of my quilts, I rarely follow her advice about extra backing and batting.

What am I not seeing? What is the importance of having extra batting and backing fabric?

Thanks.

- Jillaine

The quilt top will often "grow" as it is quilted from the center out. If the top and back are exactly the same size, you might end up with the top being larger than the backing.

I love her method! My quilts are much better now! I don't know y either, I've done it with extra and some without both were fine.
I'm just learning to quilt so any suggestions welcome!!

the reason for the need to have extra batting/backing is because as it is quilted the fabric (draws up) just like when you embroider or applique (which is why we cut our squares to be embroidered/appliqued larger-then trim to size)
it also allows for the chance of things not being exactly square- after the quilt is quilted the batting/backing is trimmed to size-the quilt can then be squared.
if your backing/batting is the same size as your top by the time you are reaching the end of the quilt chances are you will have top left-and no backing/batting
it also takes into account the top and bottom being attached to the leaders- loaded for long-arm quilting-

Are you handquilting? I know that's what you do when handquilting- as Lisa said, it will spread as it gets quilted from the center out, and you don't want to be caught short. Also, it's possible that it could shift a bit to one side or the other.

I fold the excess over to the front and baste it down while in the quilting stage, it protects the edges and helps keep them from fraying.

I'll tell you why I like having at least 6" of extra batting on the edges and it has nothing to do with quilting the piece I'm working on.

The bits I cut off are perfect for practicing FMQ on!! Every time I begin a new quilt, or a new quilt pattern I practice practice practice!!

ditto...plus for LA's it gives room to test tension of the batting and the backing being used.

If you ever have one shift on you, you'll remember to leave extra. Nothing worse than tearing out all the quilting to start over with a bigger piece. I never leave less than 4 inches......make that now I never leave less than 4 inches.

Fascinating! Thanks for these answers.

But here's what this raises for me: if the top "grows" when quilting, wouldn't the back grow at the same rate?

Why would the top grow and not the back? They're both being quilted.