Can you change yarn in the middle of a row?
To join new yarn in the middle of a row, when about 36 inches of the old yarn remains, work several more stitches with the old yarn, working the stitches over the end of new yarn (shown in double crochet). Then change yarns in stitch as previously explained.
What happens when you run out of yarn while crocheting?
When you run out of yarn and need to add another ball to your project, stop when you have about 6″ left of your current ball. Stop your last stitch with two loops left on your hook before completing the stitch. Then place a loop of the new ball tail on the hook and draw through the last twp loops to finish the stitch.
How much yarn should you leave to cast off?
My rule of thumb is to leave 3 times the amount of yarn needed for a row for a regular bind off. JSSBO, I’ll go 4 times or more. So if you used 3.5 yards for a pair of rows, you will need 1.75 yards (half) times 3 or 5.25 yards or 7 yards if you need 4 times.