This uses the combination of clusters and spaces as in a traditional granny square, but creates a straight line of stitches instead of a square. Rather than give a specific pattern, these are basic instructions that can be used to make different-sized blankets. The stripes can go lengthwise or the width of the blanket.
It is a good project to use leftover yarn with. The rows can be alternated with black yarn or it can all be done in colors. Once the first two rows are done, it is a repetition of two rows that are slightly different from each other. One row has a single double crochet at the beginning and end of the row. The other has two double crochets at the beginning and end of the row. Change colors at the end of a row, when there are two loops on the hook for the last stitch, finish the stitch with the new color. You can fasten off the old color or carry it along. If you carry the yarn along, do an edging around the finished blanket to cover the carried along yarn. Adding picot stitches to the edging will give it a nice look. To do the picot edging, chain three and then single crochet into the bottom chain and attached to the next stitch.
There is no set hook size, though CeeCee likes using a J-10 (6mm) or K-10-1/2 (6.5mm).
Chain a multiple of 3, plus 1.
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Row 1: Sc in second ch from hook, sc to the end. Turn.
Row 2: Ch 3 & dc in the same stitch (the ch3 counts as a dc), *skip 2 stitches, 3dc in the next stitch*, repeat from *to* until there are 3 stitches left, skip two stitches 2dc in the last stitch. Turn.
Row 3: Chain 3 (counts as dc), 3 dc cluster in the space, continue 3 dc clusters in spaces, dc in last stitch. Turn.
Row 4: Ch 3 (counts as dc) dc in same stitch, 3 dc cluster in space, continue 3dc cluster in spaces, making 2dc in last stitch. Turn.
Repeat Rows 3 & 4 until desired length or width.
Last Row: Sc across, fasten off. Weave in the ends.
Edging as desired.
To make different-sized blankets, make a swatch and figure out the gauge of how many stitches per inch, then multiply depending on the finished size desired.
Approximate sizes for blankets.
Toddler: 42" by 52"
Lapghan: 40" by 48"
Small Throw: 52" by 60"
Large Throw: 60" by 72"