How to Darn Wool Socks: Step-by-Step Guide 2026

A hole in the heel doesn't mean the sock is finished — 20 minutes with a needle and matching yarn brings a wool sock back to daily rotation, and it's cheaper than replacing a pair every winter.

Why this matters

Wool socks wear at the heel and big toe first because that's where friction concentrates with every step. A £14-£16 pair of wool-blend socks can last several winters if you catch the thin patch before it becomes a hole and reinforce it rather than binning the pair.

Darning isn't a lost skill from your grandmother's era — it's a five-minute maintenance habit that keeps a wardrobe of good wool socks in service for years instead of one season. At Nordic Sock Company, the socks are built from wool-blend yarn dense enough to take a repair, which is exactly why darning them is worth the ten minutes.

What you'll need

• A darning egg, or a substitute with a smooth curved surface — a tennis ball, a light bulb (unplugged, obviously) or a smooth wooden doorknob all work
• A darning needle — blunt-tipped, with a large eye, so it slides between fibres instead of splitting them
• Wool yarn or embroidery thread in a matching or contrasting colour, roughly the same weight as the sock yarn
• Sharp scissors
• Good light and 15-25 minutes uninterrupted
• A sock worth saving — thick wool socks such as Ultra Warm Finnish Wool Socks in black take a darn especially well because the dense weave gives the repair threads something substantial to anchor into

Avoid cotton sewing thread. It's thinner and stiffer than wool, and it saws through the surrounding fibres within a few wears instead of blending in.

The steps

1. Assess the damage and trim loose threads

Turn the sock inside out and look at the hole against the light. Snip away any frayed or curling threads around the edge with sharp scissors — don't pull them, just trim flush. This stops the hole from spreading further while you work and gives you a clean edge to darn around.

Common mistake: cutting too close and widening the hole. Leave a couple of millimetres of intact fabric at the edge.

2. Insert the darning egg or substitute

Push the darning egg (or tennis ball, or bulb) into the sock so it sits directly under the hole, stretching the fabric taut but not overstretched. This gives you a firm, curved surface to stitch against — trying to darn a sock lying flat on a table produces puckered, uneven repairs almost every time.

Expected outcome: the hole sits smooth and slightly domed, with no wrinkles pulling at the edges.

3. Anchor the warp threads

Starting about 1cm outside the hole, weave your needle in and out of the existing sock fabric to anchor the first thread, then run parallel threads straight across the hole, spacing them 2-3mm apart. These are your warp threads — the scaffolding the rest of the darn sits on. Leave small loops at the turnaround points rather than pulling tight, since wool relaxes and tight turns pucker the fabric once you wash the sock.

Common mistake: pulling threads drum-tight. Wool needs a little give or the patch feels stiff underfoot.

4. Weave the weft threads over and under

Working perpendicular to your warp threads, weave the needle over one thread, under the next, all the way across, then reverse the pattern on the way back. This over-under weave is what gives darning its woven-basket strength — it's the same structure as the sock's original knit, just rebuilt by hand. Keep going until the hole is fully covered and the weave feels dense enough to match the sock's original thickness.

Expected outcome: a small woven patch that mirrors the surrounding knit, roughly matching the sock's original density.

5. Reinforce the edge with a whip stitch

Once the weave is filled in, run a row of small whip stitches around the perimeter where the darn meets the original fabric. This is the step most guides skip, and it's the one that determines whether the repair survives ten wears or fifty — without it, the darn's edge is the next place to fray.

Common mistake: stopping after step 4. The weave alone is strong; the edge reinforcement is what stops it unravelling at the seam.

6. Wash and check the fit

Turn the sock right-side out and hand wash or use a wool cycle at 30°C, then lay flat to dry. Try it on before you call the job done — a lumpy darn under the ball of the foot is uncomfortable, and it's easier to unpick and redo a fresh repair than to live with one that pinches.

Worth darning, not replacing

Ultra Warm Finnish Wool Socks - Black

Ultra-thick wool socks made in Finland — dense enough to take a darn and keep going for years.

£16

Ultra Warm Finnish Wool Socks - Charcoal Grey

Certified Finnish wool, knitted thick for repeated winters — and repeated repairs.

£16

Hand Knitted Wool Finnish Socks

Hand knitted in rural Finland by experienced knitters — built to be mended, not discarded.

£28

Troubleshooting

• The darn puckers after washing. You pulled the warp or weft threads too tight. Unpick and redo with slack loops at every turn — wool needs room to relax.
• The hole is too big to darn (more than 3cm across). Cut a small patch from an old sock's cuff or heel and stitch it in place first, then darn over the join for extra strength.
• The wool has felted and shrunk since the hole appeared. This usually means the sock was washed too hot. Darn it anyway if the fit still works, but wash future loads at 30°C on a wool cycle from now on.
• The repair feels lumpy under the foot. Your weave is too dense in one spot. Unpick that section and re-weave with threads spaced slightly further apart to match the original knit tension.
• Matching yarn isn't available. Use a contrasting colour deliberately — visible mending is a legitimate finish and holds just as well structurally.
• The needle keeps splitting the wool fibres. Switch to a blunt-tipped darning needle rather than a sharp sewing needle; sharp points cut through fibres instead of sliding between them.

FAQ

Tools and resources

• Darning needle and darning egg — available from most haberdashery shops or online craft suppliers
• Wool yarn matched to your sock, or a contrasting colour for visible mending
• Guidance on washing merino wool socks without shrinking them — the wash cycle you use after darning matters as much as the repair itself
• A sock worth the effort: thick, dense wool-blend socks hold a darn better than thin cotton-mix ones

What to do next

Once a repaired sock is back in rotation, the next question is keeping the rest of the drawer in good shape between seasons — moth damage does more harm to stored wool socks than everyday wear ever does.

One last thing

The strongest darns rarely use matching thread. Visible mending in a contrasting colour, deliberately placed, holds up better over time than colour-matched repairs because the darner tends to weave it tighter and more carefully when the stitching is meant to be seen — vanity turns out to be a decent quality control mechanism.

Related guides

• How to store wool socks over summer
• How Nordic wool socks are made