What Is Quilt Binding?A quilt's binding is the fabric that's used to cover the raw edges of the quilt sandwich (top, batting and backing) after the quilt is quilted. Binding is one of the last steps before you can finally say it's finished.
Quilt binding can be narrow or wide, depending on the look you're trying to achieve. You can bind with a fabric that's already in the quilt or you can choose something different. Binding can be made from a single layer of fabric, but two layers are lots more more durable.
Which Fabric Grain Is Best for Binding?Lengthwise grain strips have threads that tend to run fairly straight along their length, ending up parallel to the edges of the quilt. If a single thread becomes weakened and breaks, it could split the binding along one entire side of the quilt, traveling as far as the weakened thread travels.
That scenario is most likely to be a problem for quilts that are used and laundered, both actions that make the raw edges under the binding rub against it abrasively.
Crosswise grain fabric strips are a good choice for binding. The grain isn't usually perfectly straight, so there's less risk that a split would damage an entire side -- it would be more likely to travel a short distance then stop when it butts into the quilt's front or back. Crosswise strips are also stretchy enough to wind around large curves along a quilt's exterior.
The grain in bias binding strips runs at an angle, so it moves from front to back after the binding is sewn to the quilt. A split would affect a fairly small area of the quilt's edge, giving you more time to make repairs.
Stretchy bias strips are the best choice for binding tight curves and deep angles, but crosswise binding is perfectly fine for most quilts.