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Mold in a mattress is a fungus that thrives in damp conditions. Mold shows as dark spots, a musty smell, and causes allergy-like symptoms.
Surface mold can be cleaned off, but when mold grows deep in the foam, you need to replace the mattress.
The longer you leave mold untreated, the deeper it spreads and the more spores you breathe in each night.
We researched the symptoms, treatment, and causes of mattress mold, and how to stop it from coming back.
This guide is for anyone dealing with mold in a mattress, or trying to prevent it.
The symptoms of mold in a mattress include physical signs you can see, smell, or feel, and health symptoms that develop in the sleeper.
A moldy mattress shows physical signs you can spot before any health symptoms appear, such as a musty smell, dark patches, or a damp surface.
Check for the following signs.
Mattress mold can also cause health symptoms, mainly allergic and respiratory reactions to the spores it releases into the air.
Watch for the following reactions.
Spotting these signs early is important because mold that spreads deep into the foam is far harder to remove than a fresh patch on the surface.
To get mold out of a mattress, vacuum away the loose spores, treat the surface with hydrogen peroxide or diluted white vinegar, then dry the mattress completely.
A mattress is porous, and porous materials that grow mold can be impossible to clean fully and may need to be thrown away (EPA).
Act as soon as you spot the signs, while the mold is still on the surface.
Vacuum and air the mattress first, then pick one of the surface treatments below to suit the mattress material. Call in a professional if the mold is severe or a home treatment fails.
Vacuum both sides of the mattress with a HEPA-filter cleaner to lift loose spores off the surface.
Wear a face mask while you work if you are sensitive to mold, because vacuuming can stir spores into the air.
Stand the mattress outside in direct sun for several hours on a dry day. Sunlight and moving air dry the mattress and reduce surface mold and musty odors.
Sprinkle baking soda over the mattress, leave it for a few hours, then vacuum it off. Baking soda absorbs the stale, musty smell that mold leaves behind, though it does not kill the mold itself.
Spray a mix of equal parts white vinegar and water onto the moldy area, leave it about 10 minutes, then blot it dry. White vinegar reduces surface mold and lifts light stains.
Mist the moldy area with equal parts lemon juice and water, leave it 20 to 30 minutes, then blot it dry.
Lemon juice can bleach fabric, so take care not to get it on your carpet, headboard, bed frame, or any other fabrics.
Test a 3% hydrogen peroxide solution on a hidden patch first, because it can discolor some fabrics.
If the color holds, spray the solution on the moldy area, leave it about 10 minutes, then scrub gently and blot dry. Hydrogen peroxide kills mold on the surface.
Steam clean only a traditional innerspring mattress, never foam or latex, which can be damaged by heat and moisture.
The heat of the steam kills surface mold, so dry the mattress fully afterward to stop new growth.
Mix a few drops of tea tree, clove, or lavender oil into water, mist the moldy area, leave it for 30 minutes, then wipe it clean.
Tea tree, clove, and lavender oils carry mild antifungal properties that treat surface mold.
Dab moldy spots with a cloth lightly dampened in rubbing alcohol, then let the mattress dry fully. Rubbing alcohol kills surface mold on contact.
Do not soak the mattress, because trapped moisture invites new mold.
Hire a professional cleaning service if the mold is severe or the home methods fail. A cleaning service uses specialized tools and solutions to remove mold and its spores from the mattress.
Removing the mold clears the problem for now, but mold comes back unless you identify the cause.
Mold grows in a mattress when excess moisture collects and cannot dry out. Moisture that causes mold on mattresses has various sources, listed below.
Damp air is the leading cause of mattress mold, and it gets worse in humid climates and during humid seasons.
Poor ventilation traps moisture and heat around the mattress, which happens when the mattress sits against a wall, on a solid platform, or in a room with little air movement.
As you sleep, your body gives off heat and sweat that soak into the mattress. Excessive sweat can cause damp that enables mold growth.
A spill that soaks in and is not dried out gives mold the moisture it needs to grow.
When you place a mattress directly on the floor, it has no airflow underneath it, and the cold floor draws condensation, both of which feed mold.
A dirty mattress collects dust, dead skin, and other debris that give mold more to feed on.
Damp clothing on the bed, or going to bed with wet hair, adds the moisture mold needs.
An old mattress has soaked up years of moisture, dead skin, and other material that mold feeds on.
Some materials, such as dense foam, do not breathe well and trap heat and moisture inside the mattress.
Basement bedrooms tend to be cooler and more humid, which makes a mattress there more prone to mold.
In a poorly insulated home, cold walls draw condensation. Beds pushed against cold walls can grow damp enough for mold.
Each of these causes traces back to trapped moisture, so to prevent mold, you need to keep the mattress dry.
To prevent mold in a mattress, keep it dry and let air move around it. Control the bedroom's humidity, air the mattress regularly, guard it against spills and sweat, and replace it once it is old or sagging.
Keep bedroom humidity below 50% with a dehumidifier or an air conditioner, and run one in a basement or any room that stays damp. Check the level now and then with a moisture meter.
Open a window or run a fan to move air through the bedroom, and pull the bed a few inches off the wall.
Rest the mattress on a slatted base, and lift a floor mattress to let air reach underneath.
Blot spills straight away and let the mattress dry fully before you remake the bed.
Keep the bedroom cool to sweat less, dry your hair before bed, and change out of any damp clothes before getting into bed.
Fit a mattress protector to stop sweat and spills soaking into the mattress.
A waterproof mattress protector keeps liquid on the surface, where you can wipe it away.
Vacuum, spot clean, and rotate the mattress every few months to stop debris building up.
Choose a breathable mattress, such as a bamboo one, and replace a mattress that is past the end of its lifespan or sagging.
Kept up together, these habits leave a mattress too dry for mold to take hold. If mold has already appeared, its color and texture tell you which type you are dealing with.
The six main types of mattress mold are Aspergillus, Penicillium, Cladosporium, Alternaria, Stachybotrys, and mildew.
You can tell them apart by their color, texture, and growth pattern.
All six are indoor molds that can trigger allergic and respiratory reactions (Mendell et al., 2011).
Aspergillus can also cause serious lung infections, mainly in people with a weakened immune system or a lung condition (CDC).
Stachybotrys is the mold people call toxic black mold. The CDC says there is no evidence to suggest Stachybotrys causes health effects worse than other molds (CDC).
A wet mattress can turn moldy in 24 to 48 hours. The EPA advises drying water-damaged items within 24-48 hours to prevent mold growth (EPA).
Mold grows fastest in warm, humid, still air, and more slowly in a cool, well-aired room.
Yes, synthetic mattress materials that trap moisture and dry slowly are more prone to mold than healthy mattress materials that breathe well.
To improve your bedroom's air quality, ventilate the room daily, keep humidity below 50%, and clear any mold at its source. Wash bedding regularly and vacuum with a HEPA filter to cut down on dust and spores.
For an extra step, run an eco-friendly air purifier to clear what is left in the air.
Yes, you can shampoo a moldy mattress with an upholstery shampoo.
Check the ingredient list first and choose a non-toxic formula, then let the mattress dry fully so the damp does not feed more mold.
Clean your mattress lightly every month or two, and deep clean it every six months. Increase that if pets sleep on the bed or spills are common.
Our full guide on how to clean a mattress covers the routine step by step.
If you think your child has mold poisoning, see a doctor straight away.
Signs like a lasting cough, wheezing, or a rash need a professional opinion, so do not try to diagnose or treat it at home.
Replace a mattress with mold when it has spread deep into the foam or across a large area, or when surface cleaning does not remove it.
You do not need to replace the mattress that has only a small patch of mold on the surface.
When you replace a mattress, dispose of the old one responsibly, with our guide to recycling an old mattress.
Yes, a waterproof mattress protector helps prevent mold by keeping sweat and spills out of the mattress. Choose a PVC-free protector with no added flame retardants for a non-toxic option.
A protector is one layer of defense, but keeping the whole mattress dry stops mold for good.
Mold in a mattress starts with trapped moisture, and it shows up as a musty smell, dark spots, and allergy-like symptoms.
When caught early, visible mold can be removed with a vacuum and a mild treatment. Once mold reaches deep into the foam, it's safer to replace the mattress.
Keeping mold from coming back is simpler than removing it. Control the bedroom's humidity, air the mattress, guard against spills, and let air move underneath, so the mattress stays too dry for mold and mildew to settle.
Follow these tips to keep your sleep environment healthy and mold-free.
