If the knot is not tight, the pompom won't hold together. Get creative with this lovely Rico Creative Pompon Yarn This popular yarn can be used in lots of different ways: whether for knitting unique, thick scarves. 110y Needle size:4mm Tension:8 sts,4 pompoms,to 16 rows,garter stitch,on 4mm. Pull both ends of the yarn towards yourself, then tie them together into a tight knot over the center of your yarn bundle.