i placed my tape measure at the folded edge and used a sharpie to mark 9 inches all the way around the half circle. for a smaller pumpkin try 7 inches or for a larger just increase to 12 inches or whatever you like.
once your pattern is marked, cut out your circle and unfold it.
now, take your needle and thread it with a thread at least a similar color to the fabric. then knot the end of the thread and begin to sew about half an inch from the edge of your circle. weave the needle back and forth to make half-inch stitches.
don’t forget to tighten the stitches so it 