Cleaning
How to Get Mold Out of Outdoor Cushions (and When to Replace the Foam)
Surface mildew on outdoor cushions usually scrubs off in half an hour with Sunbrella's bleach-and-soap solution. If it keeps coming back, the mold is likely in the foam, and that's a replacement job.
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Gray or black specks on your patio cushions usually show up after a wet spring or a few weeks under a damp cover. On most outdoor fabric, surface mildew comes off with a bucket, a soft brush and about half an hour. If the spots keep coming back after every wash, the problem is usually in the foam, not the fabric.
Quick answer
To get mold out of outdoor cushions, brush off loose growth, then spray the fabric with 1 cup of bleach and 1/4 cup of mild soap per gallon of water. Wait 15 minutes, scrub with a soft brush, rinse well and air dry. This is Sunbrella's method; spot-test other fabrics. If mold is inside the foam, replace the foam.
This post covers mold and mildew only. For everyday washing and stains, see our main guide on how to clean Sunbrella cushions, or our step-by-step guide to cleaning outdoor cushions.
What is the difference between mold and mildew?
Mildew is a type of mold. People use "mildew" for flat, powdery growth on top of the fabric, often white or gray. "Mold" usually means fuzzy black or green patches that can grow deeper, into the foam.
For cushions, depth is what matters. Surface mildew scrubs off. Mold in the foam can't be scrubbed out through the cover.
Why does mold grow on outdoor cushions?
Mold grows on outdoor cushions because of two things: dirt on the fabric and water that stays in the cushion.
The EPA says molds "can grow on virtually any substance, providing moisture is present." Sunbrella's own care page explains that its fabric doesn't feed mildew, but mildew "may grow on dirt and other foreign substances if not removed from the fabric." Pollen, sap, sunscreen and spilled drinks are the real food.
Water is the other half. Standard polyurethane foam soaks up rain like a kitchen sponge. The EPA advises drying wet furnishings within 24 to 48 hours to prevent mold, and a thick seat cushion lying flat after a storm often stays wet much longer.
What safety gear do you need to clean mold?
You need gloves, goggles and a mask, and you should work outside.
The CDC recommends gloves made of rubber, nitrile or vinyl, goggles that fully cover your eyes, and at least an N95 respirator. The EPA's guide to mold and moisture says most people can clean a moldy area smaller than about 10 square feet on their own.
One rule matters more than the rest. Never mix bleach with ammonia, vinegar or any other cleaner. Poison Control says bleach and vinegar together release chlorine gas, which irritates your airways, eyes, nose and throat.
Which cleaner is safe for which fabric?
For mildew on Sunbrella, a diluted bleach solution is what the maker recommends. For any other fabric, test every cleaner on a hidden spot first.
Solution-dyed acrylic is fabric where the color is added before the fiber is made. Sunbrella says its fibers are "saturated with color and UV-stabilized pigments before they're spun into yarn," which is why bleach doesn't fade them.
| Cleaner | What it does | Sunbrella (solution-dyed acrylic) | Polyester, printed or unknown fabric |
|---|---|---|---|
| Bleach solution (1 cup bleach + 1/4 cup mild soap per gallon of water) | Removes mildew stains and kills surface mold | Yes. This is Sunbrella's own mildew recipe. | Only if the fabric is colorfast. Spot-test first. |
| White vinegar (about 4–7% acetic acid) | Mild acid cleaner for light stains | Safe. Sunbrella lists it for stains like beer and urine, not for mildew. | Spot-test first. Never mix with bleach. |
| Oxygen bleach (powders like OxiClean) | Lifts stains and musty odors, but does not disinfect | Not part of Sunbrella's guide. Spot-test first. | Usually safe on colorfast, water-washable fabric. Spot-test first. |
| Enzyme cleaner | Breaks down dirt, food and other organic residue; does not disinfect | Not part of Sunbrella's guide. Spot-test first. | Made for water-safe fabrics. Spot-test first. |
Oxygen bleach is a chlorine-free bleach made with ingredients like hydrogen peroxide or sodium percarbonate. Clorox says it is safe for most fabrics but is not registered to disinfect.
An enzyme cleaner uses natural enzymes to break down organic messes like food and grime.
OxiClean's cushion directions say to leave its solution on for 5 to 30 minutes, rinse with cool water, and use it only on colorfast fabric. Colorfast means the dye won't run or fade when cleaned.
How do you get mold out of outdoor cushions, step by step?
Follow Sunbrella's official cleaning instructions for mold and mildew on outdoor fabric.
- Put on your gloves, goggles and mask. Work outside.
- Brush off loose growth. Use a dry, soft brush.
- Mix the solution. Stir 1 cup of bleach and 1/4 cup of mild soap into 1 gallon of water. Dish soap works.
- Protect the area. Bleach can spot decking, grass and clothes.
- Spray the whole panel, not only the spots. Let it soak into the fabric for 15 minutes.
- Scrub gently. Use a sponge, clean towel or very soft bristle brush.
- Rinse thoroughly. Hose until no soap is left. Leftover soap attracts dirt.
- Air dry completely. Stand the cushion on its edge in the sun so the inside dries as well as the cover.
For heavy growth, Sunbrella says you can use more bleach. Clorox prefers repeat washes at standard strength, and so do we.
Is the mold on the fabric or inside the foam?
If the spots come back within a few weeks of a good cleaning, the mold is almost always in the foam.
| What to check | Surface mildew | Mold inside the foam |
|---|---|---|
| How the spots look | Flat, powdery specks on the fabric face | Dark shadows showing through the cover, often in patches |
| Smell once the cover is dry | Faint or none | Musty smell that lingers |
| After a full cleaning | Stays clean for months | Spots return within days or weeks |
| When you unzip the cover | Foam looks clean and even in color | Foam is speckled, stained or damp in the middle |
| What to do | Clean the fabric with the steps above | Replace the foam; clean or replace the cover |
What should you do when mold is inside the foam?
Replace the foam. Foam is absorbent, and the EPA says moldy absorbent materials may need to be thrown away because mold can grow into the gaps and is hard to fully remove.
You can try soaking a foam insert, but on a thick seat cushion it rarely works and takes days to dry.
You don't have to replace the whole cushion. We make every cushion as a complete cushion, a cover only, or foam only. If your cover cleans up well, order custom foam cut to your current size and reuse the cover.
If the fabric is the stained or faded part and the foam is fine, we can make Sunbrella outdoor cushion covers to fit your inserts. When both are worn out, a full set from our Sunbrella cushions range is the simpler fix.
How do you stop mildew from coming back?
Keep the cushions clean and help them dry fast. The EPA puts it simply: the way to control mold is to control moisture.
- Choose foam that drains. Reticulated foam is foam with fully open cells, so water runs straight through instead of soaking in. Our Dryfast foam is reticulated, and it's what we recommend for cushions that live outside, by a pool or on a boat. See our guide to which foam grade belongs in an outdoor cushion.
- Stand cushions on edge after rain. Water drains out and air reaches both sides.
- Rinse them often. A hose-down every few weeks removes what mildew feeds on.
- Store them fully dry. Never bag or box a cushion that's even a little damp.
- Use breathable covers. Plastic tarps trap condensation.
Frequently asked questions
Can I use vinegar to remove mildew from outdoor cushions?
Vinegar is not part of Sunbrella's mildew instructions. Sunbrella recommends a bleach and mild soap solution, or its bleach-based Renew Mold & Mildew Stain Remover. Never use vinegar and bleach together, because the mix releases chlorine gas.
Will bleach ruin my outdoor cushions?
On solution-dyed acrylic like Sunbrella, the diluted solution of 1 cup bleach per gallon of water won't fade the color. On printed or piece-dyed fabrics, bleach can strip the dye. Test a hidden spot first.
Can you save a cushion with mold inside the foam?
Usually the cover can be saved, but the foam can't. The EPA says moldy absorbent materials may need to be replaced because mold is hard to remove from them. Clean the cover, then put it on new foam.
How quickly do wet cushions need to dry to avoid mold?
The EPA advises drying wet furnishings within 24 to 48 hours to prevent mold growth. Standing cushions on edge in the sun after rain helps a lot.
Is Dryfast foam mold-proof?
No foam is mold-proof. Dryfast is open-cell reticulated foam, so water drains through it and it spends far less time damp.
Sources
- Sunbrella: How to Clean Sunbrella Upholstery Fabric
- Sunbrella: Cleaning Guide
- Sunbrella: 5 Reasons to Choose Sunbrella Color to the Core Fabrics
- EPA: A Brief Guide to Mold, Moisture and Your Home
- EPA: Ten Things You Should Know about Mold
- CDC: Mold Clean Up Guidelines and Recommendations
- Poison Control: No, Vinegar Is Not Always Safe
- Clorox: The Difference Between Chlorine and Non-Chlorine Bleach
