First, gather your materials. I used several different "autumn colored" sweaters, but you can use whatever works for you! It doesn't matter what they are made of -- cotton, wool, polyester is all fine.
To make a small pumpkin, just cut the sleeve off the sweater. (You can also make medium- and large-sized pumpkins -- see my tutorial link at the top for where to cut.)
Turn the cut sweater sleeve inside out.
Cut off a long length of thread (at least two yards) and tie the bottom edge of your sweater together tightly. Tie at the cut edge, not the cuff edge.
Glue the bottom edge of the sweater to keep it in place.
Turn your sweater right side out, with the thread hanging out the top.
Stuff your sweater with fiberfill or even just cut up sweater scraps.
Cut a one inch notch at the top of your sweater edge, right next to the seam.
Allow the thread to come out the side at the notch. Pull tightly (but don't break it).
Gather the top edge of the sweater and tie your thread around it tightly, at least one inch down from the edge.
Begin wrapping your thread around the sweater ball, from top to bottom, several times. This creates the segments of the classic pumpkin shape. Pull the thread tightly to create the shape. Aim for 6-8 segments.
Once you've got all your segments defined, wrap the thread around the top section to create the stem of the pumpkin.
Glue the end of the thread in place so it doesn't unwrap.
Cut out leave shapes in a contrasting color of sweater and glue them to the top of your pumpkin.