How to Wash Children's Jumpers: A Knitwear Care Guide for Wool, Cashmere and Cotton

Children rarely wear out a good jumper. What usually ends its life is the washing machine: a wool jumper that comes out two sizes smaller, a cotton cardigan that has stretched down to the knees, or a cashmere knit covered in small bobbles after a month.

All of these can be avoided with a few habits. Here is how to wash, dry and store children's knitwear so it lasts through a second and third child. We've also included what to look for when buying jumpers pre-loved.

 

Start with the fibre

Before anything goes in the machine, check the label. How you wash a jumper depends almost entirely on what it's made of.

Washing wool and merino

Wool shrinks when heat, agitation and sudden changes in temperature combine. The fibres lock together, a process called felting, and once that happens it can't be undone. Avoiding it is simple:

• Use the wool or hand-wash cycle at 30°C or below, with a low spin.
• Use a detergent made for wool. Many everyday biological detergents contain enzymes designed to break down protein stains. Wool is a protein fibre, so those enzymes gradually weaken it too.
• Wash inside out, with other knits or delicates, not with jeans and towels.
• Keep the temperature consistent. A cold rinse after a warm wash is one of the most common causes of accidental shrinking when hand washing.

Wool also needs washing far less often than you might expect. It naturally resists odours, so unless there's a visible mark, airing a jumper overnight is often all it needs. Small marks can usually be spot-cleaned.

 

Washing cashmere

Cashmere is finer and more delicate than wool. Hand washing in cool water with a little wool detergent is the safest method. Squeeze the water gently through the fabric, never rub or wring it, and rinse in water of the same temperature. If the label allows machine washing, use the wool cycle and a mesh laundry bag.

Cashmere and cashmere blends, such as those from Peuterey or Jacadi, become softer with careful washing. A well-kept cashmere jumper on its second child often feels better than it did new.

Washing cotton knits

Cotton knitwear is the most forgiving to wash and can usually go in the machine at 30°C. The risk is stretching rather than shrinking. Wet cotton is heavy, and a cotton cardigan hung on a line will slowly drop in length and widen at the shoulders. Wash inside out and dry flat. Organic cotton knits, which labels such as Molo and Hust & Claire use widely, respond especially well to gentle washing.

 

How to dry any jumper

Almost every knitwear disaster happens during drying rather than washing.

1. Never tumble dry. It is the fastest way to shrink wool and stretch cotton.
2. Remove water by rolling, not wringing. Lay the jumper on a clean towel, roll the two up together, and press gently.
3. Dry flat, on a fresh towel or a flat drying rack.
4. Reshape while damp. Ease the sleeves, hem and neckline back to their proper shape and size. This is your chance to correct any stretching.
5. Keep it off the radiator. Direct heat can shrink wool and make cotton stiff.

 

Dealing with pilling

Pilling is those small bobbles of fibre that form on the surface of knitwear. It happens where the fabric rubs, typically under the arms, along the sides, and wherever a school bag strap sits. It isn't necessarily a sign of poor quality. Cashmere and merino often pill early on as loose fibres work their way out, then settle.

Remove pills with a fabric comb or an electric de-bobbler, working gently over a flat surface. Avoid pulling them off by hand, which draws more fibre out of the knit. Washing inside out and reducing friction in the machine will slow new pilling considerably.

 

Fixing common problems

Stretched cuffs or necklines. Dip the stretched area in warm water, gently ease it back into shape, and leave it to dry flat. Ribbing often recovers a surprising amount of its spring.

Snags and pulled loops. Don't cut them. Use a crochet hook or blunt needle to push the loop through to the inside of the jumper, then gently stretch the surrounding fabric to even out the tension. This matters especially on pointelle and Fair Isle knits.

A jumper that has shrunk slightly. Mild shrinkage can sometimes be eased by soaking the jumper in lukewarm water with a little hair conditioner, then gently stretching it back into shape as it dries flat. Results vary, and a fully felted jumper won't recover. Remember that a jumper that has shrunk a size may simply fit a younger sibling perfectly.

 

Storing knitwear

• Fold, don't hang. Hangers stretch the shoulders and leave bumps in the fabric.
• Store clean. Clothes moths are drawn to wool and cashmere, particularly pieces that have been worn and not washed.
• Use breathable storage. Cotton bags or boxes are better than sealed plastic, which traps moisture. Cedar blocks or lavender sachets can help deter moths.
• Check stored knits before they go back into rotation. Small holes clustered in one area are a sign of moth damage. If you suspect moths, placing the garment in a sealed bag in the freezer for a few days is a common way to deal with any larvae.

For wider advice across your child's whole wardrobe, see our care guide to making kids' clothes last longer and our tips on children's clothing storage.

 

What to check when buying knitwear pre-loved

A few points worth checking on any pre-loved jumper or cardigan:

• Pilling under the arms and along the sides.
• Felting. Areas that feel thicker, matted or stiffer than the rest, often at the cuffs, suggest the jumper has been washed too warm.
• Small holes. Hold the jumper up to the light and look for tiny holes, especially where the knit is fine.
• Cuffs, hem and neckline. Check that the ribbing still springs back.
• The inside. On Fair Isle and motif knits, check that the loose strands on the reverse are intact and not snagged.
• The care label. Knowing the fibre tells you how to wash it.

At Blueberry, every item is checked by hand before it is listed and graded on our clothing conditions scale, with any wear or defect noted on the product page. We explain the process in how we quality check every item.

 

When they are outgrown

Well-cared-for knitwear is one of the easiest things to pass on. If your child's jumpers and cardigans are clean, free from holes and stains, and not felted or heavily pilled, they may be ready for their next family. Through our Sellback program, you send us your outgrown pieces and we make you an offer. You can choose a bank transfer or a higher value in store credit.

Frequently asked questions

Can I machine wash a child's wool jumper? Often, yes. Use the wool or hand-wash cycle at 30°C or below, with a low spin and a detergent designed for wool. Always check the care label first. Some wool and most cashmere pieces are best washed by hand.

Why did my child's jumper shrink in the wash? Wool shrinks when heat, agitation and changes in water temperature cause its fibres to lock together, which is known as felting. Tumble drying is the most common cause. Washing too warm, or rinsing in much colder water, can also do it.

How do I stop a jumper from pilling? Wash it inside out, on a gentle cycle, away from rough fabrics such as denim and towels. Pilling can't be prevented entirely, but existing pills can be removed with a fabric comb or electric de-bobbler.

Should jumpers be hung or folded? Folded. Hanging knitwear stretches the shoulders and can pull the whole garment out of shape over time, particularly heavier cotton and chunky knits.

Can you unshrink a wool jumper? Sometimes, if the shrinkage is mild. Soaking it in lukewarm water with a little hair conditioner and gently stretching it as it dries flat can help. A jumper that has fully felted, becoming thick and stiff, cannot be restored.

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Browse our pre-loved jumpers and cardigans, from fine merino and cashmere blends to everyday cotton knits, each piece checked and graded by hand.