How to Darn Socks: The Woven Darn and Swiss Darning

There is a particular smugness that comes from wearing a sock you have mended yourself. It is a small skill, learned in an afternoon, and yet it quietly undoes one of the most wasteful little habits of modern life: throwing away a whole pair of socks over a single hole the size of a five-pence piece. Darning is the old craft of weaving new fabric across that gap, thread by thread, so the sock lives on. It costs almost nothing, it uses up oddments of wool, and it is genuinely satisfying in the way that all make-do-and-mend jobs are, part thrift, part quiet handiwork on a dark evening.

This guide covers the two techniques worth knowing. The woven darn rebuilds fabric where a hole has already opened, and it is the heart of the whole business. Swiss darning, or duplicate stitch, reinforces knitting that is still whole but wearing thin, so the hole never forms in the first place. We will also look at visible darning, the modern, deliberately decorative version, where the repair becomes a feature rather than a secret. Darning sits alongside the other clothes repairs in our guide to mending clothes, and if you are working with wool it is worth reading up on working with wool too, since matching the fibre and weight is half the battle.

When to darn, patch or bin

Darning is at its best on knitted socks and jumpers, where the fabric is stretchy and a woven patch blends in. A single hole, or a worn patch up to roughly the size of a two-pound coin, is a perfect candidate. Around that, you have choices.

• Darn when the fabric immediately around the hole is still reasonably sound. You are anchoring the darn into that good fabric, so it needs something to hold onto.
• Patch when the hole is larger, or the fabric around it is thin and tired over a wide area. On woven cloth like the seat of trousers, a stitched or ironed-on patch is usually the better repair, and we cover that in mending clothes.
• Retire the sock only when the fabric has gone thin and papery over most of the foot, so there is nothing solid left to stitch into. Even then, worn-out wool socks are useful as cleaning cloths or stuffing, and pure wool can go on the compost.

The little kit

You need remarkably little, and you very probably own most of it.

• A darning needle. A blunt-tipped tapestry needle or a long-eyed darning needle is ideal, blunt so it slips between the sock's own threads rather than splitting them. Match the eye to your yarn.
• A curved former to hold inside the sock. The traditional tool is a darning mushroom or a wooden darning egg, which stretches the fabric gently over a smooth dome so you can work with both hands free. You do not need to buy one to start: a smooth jam jar, a tennis ball, a smooth pebble, a small bowl or even an orange all do the job. The light bulb is the classic make-do substitute, but treat it with care (see the warning below).
• Yarn or thread that matches the sock. Match the weight and fibre: a fine sock wool or darning wool for a woollen sock, matching thread or embroidery cotton for finer socks. Ordinary thick knitting wool tends to end up hard and lumpy. Choose a matching colour to hide the darn, or a contrasting one to show it off.
• Small scissors or snips, and a scrap of spare yarn to tie the sock to the mushroom handle if you like.

The woven darn, step by step

This is the core method. You are doing two things at once: reinforcing the worn area around the hole, and weaving a fresh little patch of fabric across the hole itself. Work on the right side of the sock, turned the way you wear it, so the neat face of the darn ends up on the outside.

How to work a woven darn

1. 1

   Set up the former

   Turn the sock so the hole sits over the curved surface of your darning mushroom, jar or ball, with the fabric stretched gently taut but not pulled out of shape. If it helps, tie the sock loosely around the handle or neck with a scrap of yarn so it stays put.

2. 2

   Thread up, no knot

   Thread a length of matching yarn onto the darning needle. Do not tie a knot. Instead, start a few millimetres out from the hole in the sound fabric, running the needle in and out a couple of times, or making a small backstitch, and leave a tail hanging that you will weave in at the end.

3. 3

   Stitch a frame around the hole

   Work a line of small running stitches in a rough square or circle around the hole, a few millimetres out into the good fabric, taking in any thin, weak areas as well as the hole itself. This frame anchors the darn and stops it pulling away. Come back to just outside one edge of the hole.

4. 4

   Lay the warp threads across the hole

   Carry a long stitch straight across the hole, from one side of your frame to the other, and take a small stitch into the fabric at the far side. Turn and lay another long thread back alongside it, and so on, filling the width of the hole with parallel threads set close together. These are your warp, the threads the weave will lock onto.

5. 5

   Leave a small loop at each turn

   As you turn at the end of each warp thread, leave a tiny loop of slack rather than pulling the thread tight. Socks stretch every time you put them on, and these little loops give the darn the give it needs so it flexes with the sock instead of puckering or snapping. Gentle tension throughout is the single most important habit in darning.

6. 6

   Weave the weft through the warp

   Now turn the work ninety degrees and weave at right angles across the warp threads: take the needle over one warp thread, under the next, over, under, all the way across, then anchor into the frame at the far side. This is a true weave, not sewing through the sock.

7. 7

   Brick each row so it locks

   On the next row back, reverse the pattern: go under the threads you went over, and over the ones you went under. Push each new row of weft up snug against the last with the tip of your needle. Row by row, an alternating over-under weave builds a small square of new fabric across the hole, exactly like the knit it replaces.

8. 8

   Fill, then fasten off

   Keep weaving until the hole is completely covered and you are back into sound fabric all round. To finish, run the needle and both tails back through the darn and the surrounding fabric several times, following the threads so nothing shows, then snip the ends flush. No knots anywhere.

Do not aim for perfection your first time. A slightly uneven early darn still works perfectly well, and darning is a craft that rewards a few goes, so your third sock will look far tidier than your first.

Swiss darning: reinforce before it holes

The neatest repair is the one you make before there is anything to repair. Swiss darning, also known as duplicate stitch, is worked over knitting that is still whole but going thin, typically at the heel, the toe or the ball of the foot where socks wear first. You trace over the existing knitted stitches with fresh yarn, following the little V-shape of each stitch, so the new yarn sits exactly on top of the old and doubles the fabric.

Because it copies the knitting stitch for stitch, a Swiss darn in matching yarn is nearly invisible, and it adds a whole second layer of wear exactly where you need it. The technique is simple in principle: bring the needle up at the base of a knitted V, pass it behind the two "legs" of the stitch in the row above, then take it back down where it came up, and move on to the next stitch. Worked across a thinning patch, it lays a fresh grid of yarn over the tired fabric. Reinforce the stitches all around the worn area, not just the thinnest spot, so the new layer is well anchored into sound fabric.

Visible darning: the pretty version

For a long time the aim of darning was invisibility, a repair so discreet nobody would know. The modern visible mending movement cheerfully throws that out. Here you darn in a bright, contrasting wool, or several colours, and let the woven patch stand proud as a little embroidered badge, a dot of mustard on a grey sock, a cluster of coloured darns like scattered sweets. It is exactly the same woven darn described above, simply worked in a colour you want to see.

There is nothing to lose by trying it. The technique is identical, the wool is often oddments you already have, and a visibly mended sock quietly announces that it was worth saving. If you are nervous about a matching darn looking messy, a visible one is oddly freeing, because a little wonkiness reads as character rather than a mistake.

Common mistakes, and how to avoid them

• Pulling the thread tight. The commonest fault by far. A tight darn puckers, stops the sock stretching, and tears out at the edges. Keep every stitch gently slack, and leave those little turning loops in the warp.
• Using knots. They lump up under your foot and work loose. Anchor with running stitches or a backstitch and weave the tails in instead.
• Yarn too thick. Heavy knitting wool makes a hard, lumpy darn that chafes. Match the sock's weight: fine sock wool or darning wool for wool socks, thread or embroidery cotton for finer ones.
• Not framing wide enough. If you only weave across the hole itself and ignore the thin fabric around it, the darn soon pulls away as that weak fabric gives next. Stitch your frame out into genuinely sound fabric.
• Splitting the sock's threads. Use a blunt needle so it slides between the existing threads rather than piercing them.
• Leaving it too late. A thumbnail-sized hole is a pleasant fifteen-minute job. A hole the size of a heel, with thin fabric all around it, may not be worth saving. Darn early, and Swiss darn earlier still.

A last word on wool and thrift

Darning pays for itself at once and then keeps paying: a scrap of wool and twenty minutes against the price of a new pair, over and over across a winter. It is calm, portable handwork to keep in a basket by the chair. Match your yarn well (our guide to working with wool will help you choose), keep your tension kind, and reinforce the thin spots before they open. Do that, and a good pair of woollen socks can last years longer than it has any right to.