Mattress mould: What it is – and how to get rid of it

Mattress mould is one of the last things you want growing around you as you sleep. As well as being unsightly and smelly, mould in your bed can affect your sleep quality and seriously damage your health.

Mouldy mattresses are a common problem in the UK. While you’ve probably dealt with mould-related issues in your home before, you may be shocked to discover what’s lurking beneath your mattress.

The good news is that most cases of mattress mould are easy to treat by yourself. Mattress mould is not necessarily a sign that your bed is on its last legs, and even the best mattresses we review here at Expert Reviews are vulnerable to mould and mildew.

In this article, we’ll explain what mattress mould is, how to spot and how to remove it. We’ll also reveal what you can do to prevent it coming back, even in our damp British climate.

Feeling the heat at night? Check out our roundup of the best cooling mattresses for hot sleepers

What is mattress mould?

Mould is a type of fungus that thrives in moist, dark environments – and that includes your bed.

It’s fairly easy to spot, thanks to its distinctive rash of black or brown spots that may look furry on closer inspection.

Mould reproduces by releasing thousands of microscopic spores that float through the air and land on surfaces around your home. Once it takes root, it continues to grow and becomes harder to get rid of.

How common is mattress mould?

The government has estimated that 3-4% of homes in England have “significant damp and/or mould”, but this only counts cases severe enough to trigger a surveyor’s health safety assessment.

In practice, mould affects far more people than this. According to the Uswitch Mouldy Nation Report 2023, 58% of people in the UK say they’ve had mould in their homes. These statistics aren’t limited to cases of mattress mould, however.

Is mould dangerous?

A 2022 report by the UK’s chief medical officer Chris Whitty noted that children who grow up with mould in the home are up to three times more likely to suffer asthma and other respiratory illnesses. The risk is so great that we’ve even seen household mould described as the “asbestos of the 21st century”.

The spores released by mould can also trigger allergic skin reactions and conditions such as eczema.

According to the NHS, mould is particularly dangerous in the bedroom for elderly people, young children and babies and anyone with a weakened immune system, such as those going through chemotherapy.

Is my mattress mouldy?

It’s important to know how to spot mattress mould before it becomes a problem.

If you have a conventional sprung mattress, you should be in the habit of turning it often (according to the retailer Mattress Online, this is at least once every three months) to help keep it in shape. When turning, check for small black spots on the mattress’s underside. These indicate the start of a mould infestation.

Most hybrid mattresses are not designed to be turned, but you should lift them regularly to check for those telltale black spots.

If the spots are off-white or pink, they may be mildew instead of mould. That’s good news, because mildew is easier to clean and doesn’t grow into the mattress like mould.

However, if the spots are purple, brown or green, it suggests that the mould growth is well established and you may need to replace your mattress.

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How can I remove mattress mould?

Mould at the “black spot” stage is fairly easy to remove from a mattress by yourself. Start by removing all the bedding, then stand the mattress up so you have easy access to the mouldy area. Then follow these steps:

1. Vacuum your mattress

Thoroughly vacuum all surfaces of the mattress, focusing on the underside but not ignoring the top and sides. Use your vacuum cleaner’s nozzle attachment to get into the creases of your mattress. Empty your vacuum cleaner afterwards to prevent mould spores spreading.

2. Put your bedding on a hot wash

Wash your duvet cover and other sheets at the highest temperature their labels allow. The hotter the wash, the better your chance of killing any spores that transferred from your mattress to your bedding.

3. Scrub all areas affected by mould

Clean the affected area with a soapy solution. Don’t go overboard with water, because excessive moisture can aggravate the problem. Rub in a circular motion on the mould spot and go well beyond the area of visible mould.

A bleach/water solution can help to clean mould, but bleach is corrosive and may damage the fibres of your mattress as well as cause colours to fade. Instead, we suggest using one or more of the following:

• Laundry liquid diluted in warm water;
• Rubbing alcohol mixed half and half with water;
• A dedicated mould remover such as Furniture Clinic Mould Remover Spray (around £10 on Amazon), which featured in our list of the best mould removers as the best mould remover for fabrics, furnishings and carpets;
• Baking soda (bicarbonate of soda), whose high alkaline pH (around 8) is too high for mould to thrive. Soda also absorbs moisture and removes unpleasant odours;
• White distilled vinegar which, like baking soda, has been used as a mould cure and natural disinfectant for generations.

4. Dry the mattress out

Let the mattress dry out completely before you put any sheets back on it. The best way to dry it is in direct sunlight, because UV light kills mould spores as well as dust mites. A dehumidifier may also help (more on these below).

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How can I stop my mattress getting mouldy?

The main cause of mould is damp air, so the best defence against mattress mould is a dry and well-ventilated bedroom. Here are a few ways to achieve this:

Keep your bedroom cool

Mould prefers warmer bedrooms than humans do. It thrives in temperatures between 21 and 30°C, while humans sleep best at temperatures of up to 19°C. By coincidence, 19°C is the recommended maximum temperature for libraries to avoid mould in their books.

During a heatwave, a fan or air conditioner may be the only way to keep your bed down to 19°C at night. Keeping your curtains or blinds closed by day helps, because this stops the sun heating up the room.

Use a dehumidifier

Our breathing and perspiration at night means moisture on our sleeping surface, putting bedrooms in second place behind bathrooms as a hotspot for mould in our homes.  Given how wet it can get in the UK, leaving a window open all year round is not a practical fix for damp indoor air, so we recommend using a dehumidifier to keep the air dry and clean.

The best dehumidifiers we’ve tested offer a quiet, low-energy way to reduce humidity, filter your bedroom’s air and cut the risk of mould.

Switch to a slatted bed base

Solid divan-style bed bases may be less squeaky than slats, but they come with a higher risk of trapping damp air and letting mould thrive. If mould is a potential problem where you live, switch to a slatted base that gives the air more space to circulate. Our roundup of the best beds you can buy includes beds with slatted bases for under £250.

For similar reasons, we don’t recommend keeping your bed on the floor or stacking one mattress on top of another.

Consider a latex mattress

Latex mattresses are naturally resistant to mould and bacteria as well as being very comfortable. These mattresses have an open-cell structure that makes them breathable as well as cushioned and supportive.

Latex can be pricey, but if you have struggled with mould and breathing problems and you’re looking to upgrade your bed it may be a wise investment.

Turn your sprung mattress regularly

As mentioned above, sprung mattresses should be turned every three months to keep their support consistent and help them last. Turning has the added benefit of airing your mattress’s surfaces, keeping them healthy and mould-free.

Give your bed-in-a-box some air

Bed-in-a-box mattresses such as the hybrid mattresses we review here at Expert Reviews are not usually designed to be turned, but they should still be aired regularly, especially when the weather is damp.

When you’re cleaning your sheets, stand the mattress up and inspect its underside for signs of trouble. Let the sun’s UV rays get to its underside for a few hours if you can.

Don’t get your bed wet

Spills happen, but there are ways to cut the risk of a spill turning into a vicious circle of mould on your mattress:

• Avoid putting newly-washed bed sheets back on the bed until they’re completely dry. Even in hot weather, damp sheets can provide a nice breeding ground for mould.
• Don’t go to bed with wet hair. If you like to bathe or shower before bed, dry your hair or wear a shower cap.
• Don’t get into the habit of drinking coffee, hot chocolate or whatever takes your fancy in bed. One spillage can take a long time to dry.

Buy a mattress protector

Spills aren’t always avoidable, so we’d also recommend a good waterproof mattress protector to help reduce the risk of damp and mould.

Mattress protectors are the hidden heroes of the bedroom, guarding against dust mites, allergens and stains as well as mattress mould, and potentially saving you a lot of money on professional cleaning or a whole new mattress.