- 1). Join the yarn to the hat. If your hat was knit in the round this can be done in any stitch. If it has a seam, join the yarn at the seam. To join a new piece of yarn to the existing hat, pass your crochet hook through the chosen stitch. Loop the new piece of yarn over the hook and pull it through the stitch. Hold the loose end of the yarn secure with your finger until you have made the first single crochet to avoid pulling it all the way through the stitch.
- 2). Single crochet in the next stitch. To do this, pass your crochet hook through the stitch and loop the yarn over the hook once. Pull the loop through the stitch. You now have two loops on your hook. Loop the yarn over your hook once more and draw this loop through both previous loops on the hook. You now have a single loop on your crochet hook and are ready to begin the next single crochet stitch.
- 3). Single crochet in each stitch around the bottom of the knitted hat. If you can’t clearly distinguish every stitch, focus on keeping the single crochet stitches evenly spaced. The spacing will be more obvious than the accuracy of the stitches. Work very loosely so the crochet stitches won’t hinder the hat’s ability to stretch over the head of the wearer.
- 4). Stop when you have worked all the way around and pull the current crochet loop very wide so you won’t accidentally unravel it as you examine the work. Keep the hook or your finger in the loop to keep it from unraveling as well. Carefully try the hat on at this point to make sure your crochet stitches aren’t too tight. If you can’t fit the hat around your head, you’ll need to unravel the work and try again with looser stitches. If the hat fits, proceed to the next step.
- 5). Slip stitch in the first stitch you made. Finish off by trimming the end of the yarn and bringing it all the way through the stitch to make a knot. Weave the end of the yarn into the edging of the hat and trim any remaining excess.
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