Mouldy Outdoor Cushions: How to Clean Them and Keep Them Dry Through the Wet

Sunday 1 November is the official start of the tropical cyclone season, according to the Bureau of Meteorology, which counts it from 1 November to 30 April. In the north, that also means the build-up: heavy, sticky air, afternoon storms and a daily dose of humidity that gets into everything. Anyone who has opened a cupboard in January and found a furry grey patch on the back of a cushion knows exactly how quickly it happens.

Mould on outdoor cushions is one of the most common problems we hear about, and it's almost always preventable. With a bit of planning before the wet arrives, you can keep your cushions fresh, or rescue the ones that have already turned.

Why Does Mould Grow So Fast on Outdoor Cushions in Humid Weather?

Mould grows on outdoor cushions because they stay damp and carry a thin film of food. Warm, humid air keeps the surface and the foam moist for days, and mould spores are floating around all the time. Add a coating of dust, pollen, sunscreen, skin oil and the odd spilt drink, and you have everything mould needs to take hold.

The foam is usually the real culprit. Ordinary foam acts like a sponge. It soaks up rain and sprinkler water, and then it holds on to it long after the fabric on top feels dry. By the time you can see spots on the cover, the problem has often been growing inside for weeks.

What Is the Quick Answer for Stopping Mould on Outdoor Cushions?

Keep the foam from holding water, keep the fabric clean, and give the cushions a way to dry out. In practice that means fast-draining foam, a mould-resistant fabric such as Sunbrella, a regular wash with mild soap, and storing cushions somewhere ventilated before a big storm. Our Sunbrella cushions are made to handle sun and rain, though no fabric will stay clean if the foam inside stays wet.

What Does Mould on Outdoor Cushions Look Like?

Mould shows up in a few different ways, and it helps to catch it early. Here are the signs to look for:

• Black or grey specks: Small dots, usually along seams and in the creases where water pools.

• Green or white fuzz: A soft, powdery growth, often on the underside of the cushion.

• A musty smell: A damp, earthy odour, especially when you press down on the cushion.

• Dark patches that return: Spots that come back a few days after you've cleaned them.

• A cushion that feels cold or heavy: A sign that the foam is holding water.

If you can smell it but can't see it, check the bottom and the zip. That's where growth usually begins.

Does Sunbrella Fabric Stop Mould From Growing?

Sunbrella fabric resists mould and mildew, but it can't stop dirt from collecting on the surface, and mould can grow on that dirt. The fabric is made from solution-dyed acrylic, which doesn't rot the way cotton does, so the cover itself won't break down. Sunbrella's own care guidance makes the same point, which is why regular washing matters even with a fabric that's built to last.

That's the difference between a cheap cover that mildews from the inside and a good one that only needs a wipe-down. If the fabric stays clean and dry, mould struggles to take hold. If it's coated in a month of dust and sunscreen, it's a different story.

How Do You Clean Mould Off Outdoor Cushion Covers?

You clean mould off Sunbrella covers with a mild soap and bleach solution, a soft brush and a thorough rinse. Sunbrella's cleaning guide recommends one cup of bleach and a quarter of a cup of mild soap in five litres of water. Spray it over the whole affected area and leave it for 15 minutes. Work over the surface gently with a sponge or a very soft brush, then rinse thoroughly and let the cover air dry.

Bleach can mark other fabrics, so keep it away from cushions made from different materials, and protect the surrounding furniture and paving. Avoid hard scrubbing or stiff brushes, which can damage the weave. Our guide on how to clean Sunbrella cushions walks you through the full routine, including everyday dirt that doesn't need bleach.

Can You Clean Mould Out of Cushion Foam?

Usually you can't, and trying to is a good way to waste a weekend. Mould grows deep inside open-cell foam where water, soap and sunlight can't reach it. You can clean the surface, but the spores stay behind and the smell returns the next time it gets damp.

If foam has gone black, sour or heavy, replace it. A fast-draining insert such as our Outdoor Dry Fast Foam lets water pass straight through, so the cushion dries within hours instead of days. It's a small change that makes more difference than any amount of spraying and scrubbing.

Where Does Mould Form on a Cushion, and What Fixes It?

Mould tends to form in the same few places, and each has its own fix:

How Should You Store Outdoor Cushions Before a Storm?

Before a storm or cyclone warning, bring cushions inside, and make sure they're dry when you do. Wet cushions packed away in a closed space grow mould faster than ones left outside, which is why a quick dry-off matters as much as the move.

Stack them loosely in a ventilated spot such as a garage or laundry, off the floor and away from the wall. Cotton or mesh storage bags let air through, whereas a sealed plastic bin traps moisture and invites mould. If you're short of space, store the cushions on their edges so air can move around them, and keep the covers and foam together so you can find them again.

Should You Cover Outdoor Cushions or Store Them?

Store them when you can, and cover them when you can't. A fitted outdoor cover protects against sun, rain and falling leaves, although covers that aren't ventilated can trap humidity underneath. In the tropics, that makes them a good short-term option and a poor long-term one.

The best covers are breathable and fit snugly. Our guide on what outdoor furniture covers actually protect against explains the differences between covers and why a cheap tarp can do more harm than good. For long gaps between uses, cushions inside the house are always safer.

Can You Replace Just the Cover or Just the Foam of an Outdoor Cushion?

Yes, and it's often the smartest fix. If the foam is sound but the cover is stained, a new cover brings it back to life. If the cover is fine but the foam has gone sour, a new insert is the answer. Our Sunbrella cushion covers are made for existing inserts, which keeps the cost down.

Replacing only the part that failed also means less waste. A cushion that's been mildewed three times is usually past saving, but one with a single patch of mould on the cover can often be cleaned and kept. It also pays to keep the old cover for a few weeks after a swap, so you can check that the new foam really is drying faster before you throw anything out.

Margaret ordered ten custom Sunbrella slipcovers for her furniture, and she was impressed with how the process went:

"The seller was helpful, prompt and responsive. She answered all of my questions even on weekends. Once I decided to place the order she kept me informed and the covers arrived quickly."

Margaret Tyler's custom Sunbrella slipcovers. Customer photo.

If the covers are what's worn out on your furniture, the Sunbrella Outdoor Cushion Covers are a sensible place to begin.

Can You Get Replacement Cushions for an Awkward Outdoor Seat?

Yes, and plenty of customers come to us for exactly that. A cushion that doesn't fit its seat leaves gaps and loose corners where water pools, and pooled water is where mould starts, so fit matters as much as fabric. Standard cushions rarely suit older furniture, deep loveseats or seats that curve in unusual ways, which is where our custom outdoor cushions come in. Bini had a seat that no shop could fit, and she told us what happened next:

"I couldn't find an outdoor cushion that was deep enough for my strangely-shaped loveseat. Thank you for making me a perfect set of cushions! Great communication, beautifully well sewn, fast!"

Bini's custom deep loveseat cushions. Customer photo.

For a dark, practical shade that hides the odd mark and suits most outdoor furniture, the Sunbrella Canvas Charcoal Cushion is a safe place to begin.

Is It Worth Replacing Old Outdoor Cushions Instead of Cleaning Them?

It's worth replacing them when the foam has been wet and mouldy more than once. Cleaning a cover is cheap and quick. Cleaning a sponge that's been growing mould for a season is neither, and the smell tends to return as soon as the humidity does.

A good rule is to look at the cost of your time. If you've scrubbed the same cushions twice this year, a fresh set will save you the third round. Our replacement cushions for outdoor furniture are made for the pieces you already own, so you keep the frame you like and lose the cushions that have given up. Pick fabrics and foam that suit the climate this time, and the next set should last several seasons rather than one.

Which Cushion Colours Handle Humid Weather Best?

Mid-tones handle humid weather best because they show fewer marks and dry out well in the sun. Very pale colours show every speck of mould and dust, and very dark ones can look dull when the surface is coated with salt or pollen. Heathered greys, sand and soft blues are forgiving.

A light colour in a shady spot stays damp for longer, so if your seating is under a deep verandah, a mid-tone is a sensible choice. Colours in full sun can go lighter than they started, which is less of a worry with solution-dyed fabrics.

How Do You Stop Mould Coming Back on Outdoor Cushions?

Prevention is mostly routine. These habits make the biggest difference:

• Brush off leaves, dust and bird droppings every week.

• Wash the covers with mild soap and water once a month during the humid season.

• Stand cushions on their edges after rain so the foam can drain.

• Let them dry fully in the sun before storing them.

• Keep storage areas ventilated, and never seal damp cushions into a bin.

None of this takes long, and it saves you from replacing cushions every season. A few minutes after each storm is far less work than a day with a scrubbing brush in February.

When Should You Order Outdoor Cushions Before the Wet Season?

Order before the humid months arrive. Standard Sunbrella cushions usually take two to three weeks to make, and anything cut to a template takes five to six, so there's a window to get new cushions in place before the storms start. If you'd rather have the old ones back in good shape, a refresh with new foam and covers is quicker than most people expect.

Let's Get Your Cushions Ready for the Wet

Mould doesn't have to be part of the wet season. Fast-draining foam, a clean Sunbrella cover, a regular wash and a ventilated spot to store them cover almost everything. The rest is a bit of habit.

Send us your measurements or a few photos of your outdoor seating and our team will help you choose the right fabric, foam and fit. You can contact us here or email business@fabricakraft.com to get started.