Thrum knitting is an interesting technique where tufts of fiber are added to knitted fabric. Adding the fiber creates a great deal of warmth, making it the perfect technique for projects like hats and slippers. Michele Lee Bernstein demonstrates how to make thrums and work them into a project in this video.
Michele begins by making the thrums out of a braid of roving. She pulls apart the fiber to get air in between the fiber. She makes lengths of approximately 6 inches, but mentions that you can make your thrums whatever size you like. Once she has the length of fiber, she folds each end to the center. Michele then pinches the center of thrum and rolls it in between her fingers to secure the fibers in place. Dipping your fingers into some water may be helpful to secure the ends.
Once the thrums are made, she demonstrates working them into her knitting. Thrums are typically worked on a Stockinette stitch (knit on Right Side/purl on Wrong Side) fabric. In the swatch used in the video, she is adding a thrum to every fourth stitch. On the Right Side of the work, she knits to the stitch where the thrum will be placed. She inserts the right needle as if to knit into the stitch. She places the thrum over the needle and pinches it in place. The thrum is then knit together with the stitch. This process is repeated for each thrummed stitch.
On the Wrong Side of the fabric, the thrum stitches will need to be worked through the back loops. When she comes to a thrum stitch, the purls the thrum stitch through the back loop, making sure to catch both the fiber and the yarn from the stitch it’s paired with. She notes that when working this technique in the round, the Right Side of the fabric is always facing. If working in Stockinette stitch, the thrum stitches will be knit through the back loop.