How to Clean Outdoor Cushions and Remove Mildew

Few things age an outdoor space faster than dingy, mildew-spotted cushions. The good news is that outdoor cushions are made to be cleaned, and with the right method — matched to your fabric — you can lift dirt, kill mildew, and bring tired cushions back to looking fresh. Even stubborn mold usually comes off without much trouble once you know the approach.

This guide walks through how to clean outdoor cushions step by step, how to remove mildew and mold safely on different fabrics, how to wash removable covers, and how to keep mildew from coming back for good.

How to clean outdoor cushions: routine care

Start with a regular cleaning routine, because most grime — and the damp, dirty conditions mildew loves — builds up gradually. A light clean every few weeks, plus prompt attention to spills, keeps cushions fresh and makes deep cleaning rare. Spot-cleaning a spill the moment it happens, rather than letting it dry, is the single easiest habit and stops most stains from ever setting in.

The routine itself is simple. First, brush or vacuum off loose dirt, pollen, crumbs, and cobwebs — doing this dry, before adding water, stops surface dirt from turning to mud. Next, mix a few drops of mild dish soap into a bucket of warm water and work it into the fabric with a soft brush or sponge, paying attention to seams and piping where dirt collects. Let the solution sit for a few minutes, then rinse thoroughly with a hose until the water runs clear, since leftover soap attracts more dirt. Finally, and most importantly, stand the cushions on their edge and let them air-dry completely before putting them back or stacking them, so no moisture is trapped inside.

How to remove mildew and mold from outdoor cushions

When mildew or mold shows up as black, green, or grey speckling, the right method depends entirely on your fabric, because what's safe on one can damage another. Use the table below as a quick guide, then follow the steps for your fabric type. A quick word on safety before you start: work in a well-ventilated spot, wear gloves when using bleach, and never mix bleach with vinegar or other cleaners, since combining them can release harmful fumes. Use one or the other, rinse well, and you'll be fine.

On solution-dyed acrylic (bleach-safe)

Solution-dyed acrylic — Sunbrella and similar performance fabrics — is the easiest to rescue, because its color is locked into the fiber and chlorine bleach won't harm it. Mix roughly a cup of bleach and a squirt of mild soap into a gallon of water, spray or sponge it onto the mildewed areas, and let it soak for around fifteen minutes. Scrub gently with a soft brush, then rinse thoroughly and stand the cushions up to air-dry. For most mildew, a single treatment does the job.

On printed polyester and delicate fabric (gentler methods)

If your fabric is printed, an unknown polyester, or anything chlorine bleach might fade, reach for a color-safe option instead. White vinegar — used straight or diluted with an equal part of water — is a natural mildew killer: spray it on, let it sit for ten to fifteen minutes, scrub, and rinse. Oxygen bleach, the active ingredient in many fabric-safe stain removers, dissolved in warm water works the same way without stripping color. With either one, test on a hidden area first and rinse well so no residue is left behind.

Removing common stains from outdoor cushions

Beyond mildew, a handful of everyday stains turn up on outdoor cushions, and most lift easily if you act before they set. Three universal rules apply to all of them: blot rather than rub, work from the outside of the stain inward so it doesn't spread, and rinse and dry fully afterward.

For food and grease, a few drops of mild dish soap in warm water is ideal, because dish soap is made to cut grease — work it in, let it sit a few minutes, and rinse. Sunscreen and body oils respond to the same soapy solution, though heavier oil marks may need a second pass. Bird droppings are easiest once dry: let them harden, gently scrape away the bulk, then clean the spot with soap and water. Drink spills and wine come up with a soapy solution, and for a lingering tannin tint, oxygen bleach is the color-safe follow-up. Tree sap and sticky residue loosen with a little soap and patience rather than hard scrubbing. Whatever the stain, the sooner you treat it the less likely it is to become permanent, and a quick blot at the table often saves a full cleaning later.

How to wash outdoor cushion covers

Many outdoor cushions have removable, zippered covers, which makes deep cleaning easier — but wash them only the way the care label allows.

If the label permits machine washing, use a cold, gentle cycle with a mild detergent, adding oxygen bleach for mildew if needed. The cardinal rule is to air-dry, never machine dry, for the same reasons above. A useful trick is to put the slightly damp covers back on the foam and let them finish drying in place, which helps them keep their shape and fit snugly rather than shrinking. If the covers aren't removable or are hand-wash only, clean them in place using the soap-and-water routine or the appropriate mildew solution, rinse thoroughly, and stand the cushions on edge to dry. Whatever the method, make sure both the cover and the foam inside are completely dry before the cushions go back into use. If you're between washes, a quick wipe of the covers with a damp, soapy cloth keeps them looking presentable without a full soak, which buys time until you can give them a proper wash.

Cleaning foam and deep-set mildew

Sometimes mildew works its way past the cover and into the foam, especially if cushions have sat damp for a while. Surface cleaning won't fix that, so you'll need to treat the foam itself.

Unzip and remove the cover, then clean the foam with the same bleach or vinegar solution that suits the situation, working it in and rinsing thoroughly. The critical part is drying: the foam has to dry all the way through, or the mildew simply returns. Stand it somewhere with good airflow and let the sun help, since sunlight is a natural mildew killer and speeds drying. Quick-dry, open-cell foam handles this well and bounces back. Standard foam that's been deeply colonized by mold, though, can hold the smell and spores no matter how you clean it, in which case replacing the insert is the more reliable fix. To avoid reaching that point, treat any musty smell early, before visible mold has a chance to spread through the foam.

Mildew feeds on the dirt and damp on a cushion, not the cushion itself — keep it clean and dry, and mildew has nothing to grow on.

How to prevent mildew on outdoor cushions

Cleaning mildew is satisfying, but preventing it is far easier — and it comes down to denying mildew the two things it needs: moisture and food.

Keep cushions dry above all else. After rain, stand them on edge so water drains and air circulates, and never store them while they're damp. When they're not in use for a stretch — overnight in wet weather, or over the off-season — tuck them into a deck box, garage, or indoors, since time out of the elements does more to prevent mildew than anything else. Clean them regularly so there's no dirt or organic film for mildew to feed on, and keep the fabric's water-repellent finish fresh by re-treating it periodically, so moisture beads off rather than soaking in. Starting with quick-dry foam and a solution-dyed performance fabric makes all of this dramatically easier, because the cushions dry fast and shed water by design. It also helps to give cushions airflow and a little sun rather than leaving them permanently in deep, damp shade, since stagnant, humid air is exactly where mildew thrives.

That combination — a performance fabric like the Cranbrook's, plus a simple habit of cleaning and drying — is what keeps outdoor cushions looking new season after season, even in the humid, mildew-prone climates that are hardest on them. Browse the full outdoor collection for pieces built with quick-drying, easy-clean cushions.

Outdoor cushion cleaning questions, answered