Curvy Seam Allowance, Straight Seams

Recently a knitter asked me about how to seam the Peacock sweater. Great question, Beryl! Especially since the seams are all wavy as the peacock lace stitch distorts the rows of knitting, making them move and dance across the row. Naturally you don’t want a scalloped shoulder seam; the same goes for the armholes. The ideal is for the seams to be straight.

Lacy baby cardigan with self-patterning yarn on sleeves and border on hem in a scalloped stitch pattern.

To avoid unsightly scalloped seams, literally sew a straight line across the shoulder seams and sleeve tops. Don’t be tempted to follow the bind-off edges. For these seams I really like crocheting them together with slip stitch because it’s easier to match the two sides up stitch by stitch. When I open the seam the two pieces match up perfectly with a mirror image of all the increases and decreases in the lace stitch pattern.

Shoulder Seam

Wrong side of knitting showing with two pins; the bind-off edge is scalloped; a crochet hook has one stitch on it and is held horizontal, drawing a line across the knitting showing where to stitch a straight line.

Pin the pieces with right sides together. Lie the crochet hook along the seam to see where the path for your stitches should be.

Crochet hook is inserted in knitting several rows below the bind-off edge, but in line with the straight line of seam stitches.

Insert the hook into a stitch (it’s fine if it’s a few rows below the bind-off edge). In this photo, the hook is going through the stitch between the two yarnovers and it’s about five rows down.

Two pieces of knitting pinned together but seam allowance opened up to show crochet hook about to go through back piece in same location as it when through the front piece.

Insert the hook into the same stitch on the back piece.

Crochet hook inserted through two pieces of knitting and finger holding seam allowance open to show location of hook; yarn is wrapped around the hook.

Draw the yarn through both pieces of fabric with the crochet hook and slip it through the loop already on the crochet hook.

Left hand holding knitting and tensioning yarn for crochet hook that's being used for seam.

One stitch completed.

A turquoise slip stitch seam being worked with a crochet hook on a rust piece of knitting with a zig-zaggy top edge.

Here are front and back views of a line of stitches in a contrasting colour so they’re easier to see.

Wrong side of crochet seam showing short straight stitches in a contrasting colour all lined up one after another.

Back view of the same slip stitch crocheted seam.

Wrong side of garment with scalloped seam allowance on shoulder seam spread open.

Straight shoulder seam of a back and front opened up and viewed from the right side.

Completed shoulder seam, both inside and out.

Sleeve Top Seam

Joining the bind-off edge at the top of the sleeve to the armhole selvedge is similar to the shoulder seam. The seam line should create a straight line across the top of the sleeve and should not follow the meandering bind-off edge.

Wrong side of armhole seam showing edge of armhole with the top of the scalloped sleeve seam allowance popping up behind it.

Armhole seam viewed from the other side showing just the scalloped sleeve top and the straight stitches created on the back side of the crocheted slip stitch seam.

Here are front and back shots of the armhole seam.


Take special care to follow along the space between columns of stitches along the straight selvedge edge on the body. Be sure to join the pieces one stitch in from the edge.

Beautiful seam showing a clean, straight armhole seam.

Poorly worked seam showing that the seam stitches have jumped back and forth between the columns of knit stitches.

Here’s a shot of a messy seam that sometimes goes in an extra half stitch or more from the edge. See how much nicer the carefully stitched seam is by contrast?