Written by Angela Reviewed by Daniel

Why Your Mattress Smells Musty (And The Easy Fix That Works)

If your bedroom smells damp or stale, your mattress could be to blame.

That musty odour isn’t just unpleasant, it’s usually a sign that moisture has built up inside your mattress, creating the perfect environment for bacteria and mould to grow.

The good news? You don’t need to replace your mattress just yet. A simple pantry staple can fix the problem quickly, as long as the smell isn’t caused by deeper damage.

Table of Contents

What’s Causing The Musty Smell In Your Mattress?

The most common culprit is trapped moisture. In the UK, where homes often deal with cold rooms, poor airflow or high humidity, mattresses can easily absorb damp without anyone noticing.

Common causes include:

Night sweats soaking into the fabric
Spilled drinks or water that wasn’t dried properly
Damp clothes or towels left on the bed
Lack of airflow beneath the mattress
Storing mattresses in lofts, garages or basements

Over time, this creates the kind of damp conditions that allow bacteria and mould to grow, especially if the mattress is rarely aired out.

Is It Unsafe To Sleep On A Musty Mattress?

In most cases, a musty smell is a sign of mild dampness, not something harmful. But if the odour is strong, persistent, or paired with black spots, there could be mould growing deeper inside the mattress.

This could trigger allergies, asthma or skin irritation, especially in children, older adults or anyone with a weakened immune system.

If symptoms worsen at night, or you can see visible mould, it’s best to act quickly and consider replacement if cleaning doesn’t solve it.

The Best Way To Remove Musty Smells From A Mattress

For mild smells with no visible mould, bicarbonate of soda is your best bet. It’s a gentle, natural deodoriser that absorbs odour and draws out moisture.

Here’s what to do:

Strip the bedding and let the mattress air out near an open window.
Sprinkle bicarbonate of soda over the entire surface.
Leave it to sit for at least 6 hours or overnight.
Vacuum thoroughly using a brush or hose attachment.

Repeat this process if needed. Flip the mattress and treat the other side if both surfaces smell. Make sure the mattress is completely dry before replacing bedding.

If your mattress is made from memory foam, latex or has special coatings, always check the care label first. Some materials may not tolerate heavy vacuuming or certain powders. When in doubt, test a small patch or contact the manufacturer.

Also, bicarbonate of soda doesn’t kill mould spores or bacteria, but it does reduce surface odours and absorbs excess moisture.

Tips To Prevent The Smell From Coming Back

Once your mattress smells fresh again, a few simple habits can keep it that way:

Let your mattress breathe by folding back the duvet daily and opening windows.
Use a breathable, waterproof mattress protector to block sweat and spills.
Wash your bedding weekly, especially pillowcases and sheets.
Avoid sleeping on the bed with wet hair or damp clothing.
Vacuum your mattress monthly to remove dust and moisture.
If your home is humid, a small dehumidifier in the bedroom can make a big difference.

When To Replace The Mattress Instead

If the musty smell keeps coming back no matter how many times you clean it, it could be a sign that the mattress is no longer fit for use.

Persistent odours, visible black mould spots or dampness deep within the layers often mean the problem has gone beyond surface level fixes. You might also notice sagging, a loss of support or that your sleep has been affected.

In some cases, a smelly mattress can even trigger breathing problems, skin irritation or worsen existing allergies. If you’re experiencing any of these issues, it’s usually a sign the mattress has reached the end of its life.

Most mattresses should be replaced every seven to ten years, depending on their quality and how often they’re used. If your mattress is causing more problems than comfort, it’s probably time to invest in a new one.

Know Someone With A Musty Mattress? Share This Easy Hack!

This effective and low effort hack is perfect for anyone short on time but tired of musty odours. Share it on social media to help others enjoy a fresher, cleaner sleeping space!

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