How to join crochet squares with a flat sewn seam

Prepare matching edges

Wash and dry both squares by their yarn labels before checking dimensions. Lay them side by side, right sides up. Match the corners and count the edge stitches between them.

This page covers joining flat squares edge to edge. Finishing a round with a needle join is a different use of “invisible join”; that method is described below. No seam is guaranteed to disappear in every yarn.

Sew a flat join

1. Thread a yarn needle and anchor its tail through the back of the first square. Align both corner spaces without stretching either square.
2. Pass under the inner loop of the next edge stitch on the first square. Pass under the matching inner loop on the second square.
3. Continue alternating between edges, taking one matching pair at a time. Leave the thread loose enough to inspect the path.
4. After a short section, gently draw the thread until the edges meet. Flatten the squares and check that the seam does not shorten them.
5. Continue to the far corner. Weave the tail through the backs of stitches, change direction and secure it without a bulky knot.

Needle finish for a joined round

Cut the yarn and pull the tail fully through the last active loop. Thread it onto a needle. Pass under both top loops of the first counted stitch, then back down through the top of the last stitch where the tail emerged. Adjust the new loop to resemble a top V.

The sewn loop finishes the round; it is not an extra counted stitch. Keep the pattern’s starting-chain convention. For an actual gap or damaged fabric, use the repair guide instead.

If the edges do not match

A missing stitch and different gauge are different problems. Correct a count error before joining. If the counts agree but sizes differ, remeasure the washed squares and remake the one whose fabric does not suit the project.

Do not force a long edge into a short edge by pulling the sewing yarn tighter. That gathers the seam and hides the cause until the piece is laid flat.