How to Crochet Blanket Edges
To crochet the edge of a blanket with a shell stitch, start by single crocheting the first stitch. After you've skipped the next stitch, make 5 double crochet stitches into the same stitch so your work grows vertically. Then, skip a stitch before single crocheting the next stitch to attach the shell. To complete your blanket, repeat this pattern on all of its edges. To use a moss stitch instead, skip the first stitch, single crochet the second, and chain the third. Repeat this pattern until you reach the corner, then single crochet around the corner.
Insert your crochet hook and single crochet (sc) 1. To begin the shell stitch, push your hook into the first stitch on 1 side of the blanket's edge. Make 1 chain on the hook and then wrap the yarn around the hook. Pull the hook through both loops to make 1 single crochet stitch. Skip 1 stitch (skip 1) and make 1 double crochet (dc) stitch. Skip the stitch after your single crochet stitch and wrap the yarn over the hook. To make the double crochet stitch, insert the hook and wrap the yarn around your hook again. Pull through the loops so you have 3 on your hook. Yarn over again and pull the hook through the first 2 loops on the hook. Yarn over and pull the hook through the last 2 loops to finish the dc stitch. Do 4 more double crochet stitches. Remember to work into the same stitch so the work begins to grow vertically. You should have a total of 5 double crochet stitches. Skip 1 and single crochet 1. Skip the stitch that's immediately after the shell and insert your hook into the following stitch. Wrap the yarn around the hook and pull it through to make a loop. Finish making the single crochet stitch to secure the shell to the border. Repeat the shell stitch across each edge of the blanket. Skip the stitch after your shell and single crochet 1. Skip 1 and then double crochet 5 stitches to make the shell. Skip 1 and single crochet 1 to secure the shell. Continue doing this along every side of the blanket. The pattern for shell stitch is: sc1, skip 1, 5 dc, skip 1 Insert the hook with the yarn into the blanket's edge. Wrap the yarn you want to use for the edge around your crochet hook. Push the hook through a stitch on the edge of the blanket. You can start at a corner or on the side of the blanket. Skip 1 stitch (sk1) and single crochet 1 (sc1) stitch. Skip the stitch first stitch and insert your crochet hook into the loop of the next stitch. Wrap the yarn around the hook and pull it through the loop so you see 2 loops on your hook. Wrap the yarn around the hook again and pull it through both loops to make a single crochet stitch. Chain 1 (ch1) and skip 1 stitch. To make 1 chain stitch, wrap the yarn around the crochet hook and pull it through the loop that's on your hook. Skip the next stitch on the edge of the blanket. Single crochet 1 and chain 1. Continue crocheting the moss edge along the side of the blanket. Make 1 single crochet stitch and then chain 1 stitch. Continue to repeat the following pattern until you come to the corner of your blanket: sk1, sc, ch1 Single crochet around the corners. To keep the corners laying flat, stop crocheting the moss stitch and switch to a single crochet stitch. If your blanket is small you may only need to make 3 to 5 single crochet stitches. Keep making single crochet stitches until you work around the corner. You can continue to moss stitch the next side of the blanket until you reach the next corner. Insert your crochet hook into the blanket's edge. Wrap the yarn for your blanket edge around the crochet hook. Push the hook through a stitch on the edge of the blanket. You can start at a corner or on a side of the blanket. Chain 1 (ch1) stitch and insert the stitch into the previous stitch. Since you'll be reverse single crocheting every stitch along the edge of the blanket, make 1 chain loop. Instead of inserting the crochet hook into the same stitch, push the hook into the stitch before your chain stitch. Yarn over and pull through both of the stitches. Wrap the yarn around the hook and pull it through both loops. Keep in mind that you'll be working this stitch from left to right instead of right to left. Repeat the crab stitch along the blanket edges. Continue to work from left to right by inserting your crochet hook into the previous stitch. Yarn over and pull through both of your loops to create a reverse single crochet stitch. Insert the hook and chain (ch) 3. Start at the beginning of 1 of your blanket sides. Insert your crochet hook into a stitch and wrap the yarn around your hook. Pull through to make a loop. Continue to wrap and pull through to create 3 chain stitches. Single crochet (sc) 1 stitch into the first chain stitch. Insert your hook into the first chain stitch that you made. Wrap the yarn around the hook and pull it through the loop. Wrap the yarn around the hook again and pull it through both stitches to make 1 single crochet stitch. Skip 1 stitch and single crochet 1 stitch. Skip the following stitch on the blanket edge and insert your hook into the next stitch. Wrap the yarn around the hook and pull it through the loop. Wrap the yarn around the hook again and pull it through both of the loops on your hook to make the single crochet stitch. Repeat the picot stitch edge for every side of the blanket. Continue the repeating following picot edge pattern: ch3, sc, skip 1, sc 
Insert your crochet hook and single crochet (sc) 1. Skip 1 stitch (skip 1) and make 1 double crochet (dc) stitch. Do 4 more double crochet stitches. Skip 1 and single crochet 1. Repeat the shell stitch across each edge of the blanket. Insert the hook with the yarn into the blanket's edge. Skip 1 stitch (sk1) and single crochet 1 (sc1) stitch. Chain 1 (ch1) and skip 1 stitch. Single crochet 1 and chain 1. Single crochet around the corners. Insert your crochet hook into the blanket's edge. Chain 1 (ch1) stitch and insert the stitch into the previous stitch. Yarn over and pull through both of the stitches. Repeat the crab stitch along the blanket edges. Insert the hook and chain (ch) 3. Single crochet (sc) 1 stitch into the first chain stitch. Skip 1 stitch and single crochet 1 stitch. Repeat the picot stitch edge for every side of the blanket. 