How to prevent leggings pilling

A legging pills for one of three reasons — and only one of them is the legging's fault. The other two happen in your machine, on your watch, in ways that are easy to fix once you know they're there.

Pilling is the small ball of tangled fibre that forms on the surface of a knit fabric where it rubs — the inner thigh, behind the knee, the inside of the elbow on a long-sleeve. It is not a sign of poor fabric, necessarily. It is a sign of friction plus weak fibre tips, and the friction is usually preventable.

Here is the diagnostic order, from cheapest to fix to most expensive.

Pilling is a story about friction. Find the friction, remove it, and a 240 gsm legging stays smooth for longer than its warranty suggests.

01. Wash with abrasive items

The most common cause and the cheapest to fix. Zippers, jeans rivets, hook-and-eye closures, hard-edged plastic buttons — every one of them is a small file working against your legging across the length of a wash cycle.

Two rules:

— Wash leggings inside out. This protects the visible outer face and concentrates any friction on the less-visible inside.
— Wash leggings in a mesh bag with other smooth fabrics — t-shirts, soft underwear, other activewear. Never with denim. Never with anything that has hardware.

A mesh laundry bag costs less than a sandwich. A bag of three lasts a year. This single change cuts pilling in half on most wardrobes we've tested.

02. Too much detergent in too little water

Modern washing machines use less water than older models, which is good for the environment and bad for the way detergent rinses. The same dose of detergent in less water means a higher concentration during the wash, more residue left after the rinse, and more friction between fabric surfaces because the water layer that should cushion them is thinner.

Use half the recommended detergent dose for a load that contains activewear. The dose recommendations on the bottle are written for a high-water-volume household wash with mud and a dog. They are not for your leggings.

If the machine has a "delicates" or "wool" cycle, use it for activewear-only loads. These cycles use more water and lower agitation. Both reduce friction. Both reduce pilling.

03. The dryer

The dryer pills more in twenty minutes than a wash does in an hour. The drum tumbles fabric against itself and against the metal walls, the heat softens fibre tips, and the friction lifts those softened tips into the small tangles that become pills.

There is no good way to dry a legging in a tumble dryer. Air dry. Flat or on a hanger, away from direct sun, two to four hours. The wait is the price of the legging looking like a legging at month eighteen.

If you absolutely must use a dryer — travelling, stuck without time — use the lowest heat setting and pull the leggings out while they are still slightly damp. Heat plus full-dry is what does the worst damage.

04. The fabric was always going to pill

Some leggings will pill regardless of how carefully they are washed. The signs are visible at point of purchase.

— Below 200 gsm. A thin fabric has shorter fibre lengths and weaker yarn structure than a denser one. It will pill earlier, full stop.
— A loose, slightly fuzzy hand. Run a thumb across the fabric. If you can feel small fibre ends standing up off the surface, those ends will be the first pills.
— A finish that hides the structure. Some performance fabrics use a chemical softener finish to make a thinner fabric feel like a denser one. The finish washes out in three to five cycles. The pilling appears after that.

The honest test is hand a 240 gsm double-knit and a 180 gsm jersey. The hand difference is visible in seconds. The 180 gsm legging will pill earlier, no matter how careful the laundry. A dense double-knit you can hand-test tells you in three seconds whether the fabric is in the right weight class.

How to remove pills that already exist

A small fabric shaver — battery-operated, twenty dollars — works. Use it on the dry, laid-flat legging, in light passes, in one direction. Do not press hard. Do not use it repeatedly on the same spot.

Do not pull pills off by hand. The pill is a tangle of fibre that is still partly attached to the fabric. Pulling brings the surrounding threads with it and creates a thin spot that will fail in the next wash.

A disposable razor works in a pinch on a flat surface, used very lightly. A piece of pumice can shave pills off a heavier knit. Both are cruder than a fabric shaver, both work.

The simple prevention routine

Inside out. Mesh bag. Half-dose mild detergent. Cold water. Air dry flat. No dryer.

That is the routine. It is the same routine our pillar — what makes the wash routine work — covers in detail, because the things that prevent pilling are the same things that prevent every other premature failure mode of a synthetic-elastane garment. A future post on lifespan ties pilling timelines to total wear count.

A 240 gsm legging washed this way pills slowly enough that most women never need a fabric shaver. A 180 gsm legging washed this way pills slowly enough to outlast its peer washed without care by a factor of two. The wash is the wear. Always.