Make it last
How to Prevent Moths in a Wardrobe
Adult moths do not eat your sweaters. Their larvae eat keratin. Cedar is a scent, not a strategy. Wash, freeze, or trap — in that order of seriousness.
Updated 16 Aug 2026 · 7 min read · how to prevent moths in wardrobe
The moth you actually have
Webbing clothes moths are small, straw-gold, and bad at flying. They scuttle along baseboards and the dark undersides of shelves. The casemaking clothes moth is less common in apartments and leaves a little portable case. Pantry moths (Indian meal moth) are a kitchen problem; they do not eat knitwear. If you are spraying the closet and the cereal, you have two pests.
You will see the damage before you see the insect: irregular holes, not the even graze of a cigarette burn, often at the underarm, collar, or fold where a knit sat dirty. Fine webbing or granular frass in a dark corner of a drawer is the larva at work. A cashmere or merino sweater is a denser keratin buffet than a Superwash tee, which is one reason the expensive knit gets hit first. Surface balls are not moths — that is pilling.
Larvae eat keratin. Adults just fly.
Keratin is the protein in wool, cashmere, angora, fur, feathers, piano felts, and hair in the vacuum bag. Cotton, linen, and polyester are not food unless they are heavily soiled with sweat or food, which is why a dirty wool blend is more attractive than a clean one. The adult moths live to mate. Killing the ones you see in the air does almost nothing to the next generation already in the cuff.
Larvae like dark, still, slightly humid folds. A tightly packed rail of unworn wool is a hotel. A capsule wardrobe you actually rotate is a worse habitat, which is an underrated argument for owning less knitwear and wearing it.
Cedar is weak. Freeze, wash, or trap.
Cedar oil is mildly repellent when the wood is freshly sanded and the closet is small and closed. A $12 block from 2019 is furniture. Refresh by sanding, or do not bother. Lavender sachets are the same story: a smell you like, not a kill step. Mothballs (naphthalene or paradichlorobenzene) work in a sealed chest and are toxic in a bedroom; they are the wrong tool for a closet you open every morning.
Wash kills. A 50–60°C cycle on anything that can take it, or a real dry-clean, destroys eggs and larvae. A 30°C wool cycle is not a guarantee — it may leave eggs. For pieces that cannot take heat, bag them (the bag must be sealed) and freeze at −18°C / 0°F for 72 hours, then thaw in the bag so condensation stays off the knit, then wash or air. A home freezer that is opened all day may not hold the temperature; do not count a three-hour “chill.”
| Method | What it kills | What it does not |
|---|---|---|
| Wash 50°C+ or dry-clean | Eggs, larvae, adults on the garment | Moths living in the carpet edge |
| Freeze, sealed, −18°C / 72h | Eggs and larvae on that piece | The closet itself |
| Pheromone trap | Adult males, as a census | Larvae, eggs, or females |
| Cedar / lavender | Almost nothing once the scent fades | An active infestation |
| Vacuum + airtight off-season bags | Habitat and leftovers | A moth already in a dirty sweater |
Closet habits that starve an infestation
Never store a knit dirty. Sweat, food, and dead skin are the buffet. Follow the care label or the merino method in how to wash merino wool, then bag off-season wool in a zip or vacuum bag, not a breathable cotton sack in a warm loft. Vacuum the closet floor, the rail ends, and under the dresser every time you swap seasons — eggs live in dust.
Pheromone traps ($10–15 for a pack of two) go low, in still air, not up on a shelf in a draft. Replace them on the printed schedule. If they fill up, you still have a population: repeat wash/freeze on every keratin piece, then trap again in two weeks. A clean, rotated closet with no dirty wool on the floor is more effective than any oil.
Questions, answered
- Do cedar blocks kill clothes moths?
- No. Fresh cedar can mildly discourage adults in a closed chest. It does not kill larvae or eggs, and the oil fades in months. Sand the block or treat cedar as décor.
- How long should I freeze a sweater to kill moths?
- Seventy-two hours at −18°C in a sealed bag, then thaw in the bag. A quick overnight in a freezer that you open for dinner is not a protocol.
- Do pheromone traps get rid of moths?
- They catch adult males so you can see activity. They do not catch larvae, which is the stage that eats the knit. Use them as a monitor after you have washed or frozen the clothes.
