How to Dye Sport Weight Wool Yarn with Black Walnuts

Materials & tools you'll need

Step 1 — Scour the yarn

Fill a large pot with water and add a splash of dish soap. Submerge the wool yarn skeins in the soapy water and gently agitate to work the soap through the fiber. Soak for about 30 minutes, or until the water becomes visibly murky with released oils and impurities. Drain, then rinse the yarn thoroughly under cool water and squeeze out the excess — this scouring step is what allows the black walnut dye to absorb evenly in later steps.

Step 2 — Mordant the yarn with alum

Fill a large pot with water and mix in alum powder according to the package instructions. Submerge the scoured yarn skeins in the mordant bath and let them soak for approximately 30 minutes. Drain and rinse thoroughly under cool water, squeezing out excess moisture. The alum mordant helps the black walnut dye bind more permanently to the wool fibers, giving you a longer-lasting colour.

Step 3 — Tie the yarn for a speckled effect

Fold or twist each mordanted skein into a pattern, securing the folds with rubber bands, string, or cloth ties. The tied-off sections will resist the dye and stay lighter than the rest of the skein, giving the finished yarn a speckled, one-of-a-kind look. Once each skein is tied, it's ready for the dye bath.

Step 4 — Simmer the black walnut dye bath

Simmer black walnuts on the stove, letting the liquid reduce down into a deep, dark dye bath. The longer and slower the simmer, the richer the brown tones you'll get once the yarn goes in to soak — plan for this step to take a few hours on low heat.

Step 5 — Dye the yarn

Add the tied, pre-treated yarn skeins to the pot with the simmering walnut dye. Stir gently and let the yarn soak in the bath for several hours, or until you've reached the depth of brown you're after. Remove the yarn and let it cool before rinsing under cold water, squeezing out excess moisture without wringing. Repeat the tying and dyeing process as needed for each remaining skein, then let all the dyed yarn dry completely before untying.

Step 6 — Rinse, dry, and finish

Once the yarn is fully dry, untie all the ties to reveal the speckled pattern underneath. Weave in any loose ends or tails with a tapestry needle, and block the yarn gently if you'd like to even out its tension and dimensions. For a final wash, hand-wash the yarn in cold water with a mild detergent, rinse thoroughly, and allow it to air dry before using it in your next project.

Frequently asked questions

How can I achieve a speckled effect when dyeing wool yarn with black walnuts?
Fold or twist each skein of bleached white sport weight wool yarn into a pattern using rubber bands, string, or cloth ties before adding it to the simmering black walnut dye bath. The tied-off areas resist the dye and stay lighter, creating a speckled, one-of-a-kind pattern across the yarn.

How do I prepare wool yarn so it absorbs black walnut dye evenly?
Start with a scouring bath: soak the yarn in warm soapy water for about 30 minutes to remove oils and impurities, then rinse well. Follow with a mordant bath using alum powder mixed according to the package instructions, soaking the yarn for another 30 minutes and rinsing again. This two-step prep helps the dye bind evenly to the fiber.

How do I simmer black walnuts into a rich dye bath?
Simmer black walnuts on the stove for several hours, letting the water reduce down into a deep, dark liquid. The longer and slower the simmer, the richer the resulting brown tones will be once the yarn is added to soak.

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