The Secrets to Flat Borders on Quilts
Measure Twice, Cut Once
Lay the quilt top on a flat surface. To determine the border strip width to cut, decide the width you want the finished border to be, then add 1/2" for seam allowances.
The length of the side borders is determined by measuring through the center of the assembled quilt center, from top to bottom, and adding a 1/2" seam allowance.
To determine the length of the top and bottom border, measure through the center of the quilt from side to side, remembering to add the side border measurements plus the 1/2" seam allowance. To make it easier, sew on the side borders first.
Plain Blocks or Pieced Corners
The easiest corner block to insert into your border is a plain block. The dimensions of your corner blocks are determined by the width of your borders. For instance, if your borders are finished at 4", your corner blocks also will finish at 4". Unfinished measurements will be 4- 1/2". This measurement is crucial if you are going to be constructing an actual quilt block for the corner.
For a pieced corner block, you can use a leftover block from your quilt, or piece a smaller version of that block to fit the border width. Something as simple as a Four-Patch or Pinwheel block adds a lot of pizzazz to your quilt. Determine what size of a block to make based on how big your borders are, your piecing skills, and how you want your quilt to look when it's finished.
Bringing It All Together
Cut the border strips on the lengthwise grain of the fabric whenever possible. It has less stretch and more stability than the crosswise grain. Crosswise grain is when you cut the fabric from the fold to the selvedge, or from selvedge to selvedge. With a crosswise cut, you'll need to piece border strips together for larger quilts.
Fold each side border strip, fold in half crosswise and press lightly to mark the center.
Fold the quilt center in half and press lightly to mark the center of the side edges.
With the right sides together, and raw edges aligned, pin and sew the side border strips to the side edges of the quilt with a 1/4" seam allowance, matching the center fold lines. Press the seam allowances toward the border.
Sew a corner stone or block to each end of the top and bottom strips. Press the seam allowance toward the border strip.
Pin and sew the borders to top and bottom edges of the quilt center, matching center fold lines, ends, and seams. Press the seam allowances toward the borders.
Compare the measurements of your assembled quilt top with the mathematical dimensions of the finished quilt top given in the pattern. Do this by taking the finished width-or length-times the number of blocks, and the finished sashing width-or length-times the number of pieces. Are your measurements the same as the pattern's instructions? If the two numbers are similar, use the pattern recommendation for the border sizes. If the figures are quite different, use your actual quilt center measurements and make any necessary adjustments.