How to Knit Thrums

Settlers in the Maritime provinces of Canada were a hardy, resourceful bunch. Facing long, cold winters, they developed a method for using scraps of wool to add an extra layer of insulation to their knitted hats and mittens. You’ll thank them for this when temperatures drop below freezing and you reach for your thrummed mittens or hat! Learn what thrums are and how to make and knit thrums along with us!

What Are Thrums?

Thrums are extra bits of wool incorporated into your knitting to provide a fluffy, warm lining. Originally, knitters salvaged scraps of weaving yarn cut off the loom or bits of roving left over from spinning yarn. These fluffy tufts mat and full with wear, creating a warm layer of felt inside your hat or mittens. Although thrums are traditionally worked into stockinette stitch, the Rose in Snow Hat & Mitten Set from Interweave Knits Gifts 2023 uses multicolored thrums in a cable pattern for a set that delivers both style and warmth.

How Do I Make and Knit Thrums?

Thrums are made with unspun wool, known as roving. With the wealth of beautiful hand-dyed roving available to modern knitters, thrums can add a decorative spark to your winter accessories. Choose roving in 100% wool or a wool/alpaca blend and avoid superwash. You want those tufts to felt!

We’ve worked a flat swatch for these how-to photos; you’ll likely be working in the round for your project. When you come to a thrummed stitch on the next round or row, knit or purl that stitch through the back loop, locking the thrum in place.

Things to Consider

Thrums add bulk to your knitted piece. As you knit your project, it might look like the mitten is so full of colorful wool that you’ll never be able to get your hand inside. Don’t worry—the wool will mat and felt with wear, and thrummed patterns are sized to accommodate the extra bulk.

As you experience the added warmth that thrums provide, you may wonder if you can add thrums to other patterns. The answer is yes, if you size up to account for the extra layer of insulation and if the extra bulk won’t bother you. Imagine how warm your toes would be in a pair of thrummed house socks. You won’t be able to send a text message while wearing thrummed mittens, but nothing is better for building a snowman!

Are you imagining a project with thrums? Tell us all about it in the comments!

Moira Engel lives and designs on the magnificent west coast of Canada. She is an ardent DIY fanatic, but knitting still holds the top place in her heart. Moira also enjoys painting with colored pencil, baking, painting, and three-dimensional print- ing. Being the wife of a tugboat captain and the mother of two provides lots of fun and inspiration.

Sandi Rosner is the technical content editor for all things yarn at Interweave. Over the past 25 years, she has owned a local yarn store, has been the creative director for a large yarn company, and has worked extensively as a freelance designer, technical editor, writer, and teacher. When she isn’t knitting, she usually has her nose in a book. You’ll find new technical content from Sandi nearly every week at www.interweave.com.