Outdoor furniture does not get dirty the way indoor furniture does. It gets colonised. Those grey green streaks on the arms of your chairs are not dust, they are mildew, and scrubbing harder is not what removes them. Knowing how to clean outdoor furniture comes down to two things: identifying what you are actually looking at, and knowing what the material can survive.
Quick answer: To clean outdoor furniture, start with warm water and mild dish soap and a soft brush, which handles most dirt on any material. For the grey green mildew that soap will not shift, use a diluted chlorine bleach solution of about 2 tablespoons per quart of warm water, but never on wool, silk, or spandex, and never mixed with anything containing ammonia. Rinse thoroughly, dry completely, and store cushions somewhere ventilated, because mildew comes back wherever it stays damp, warm, and still.
Key takeaways
- Most of what you are scrubbing is mildew, not dirt. It is a living growth and it needs killing, not just wiping.
- Mild soap first, always. Start with the gentlest thing that works and escalate only if it fails.
- Never mix bleach with ammonia or anything containing it. The combination produces toxic gas.
- Never bleach wool, silk, or spandex. Extension guidance is explicit, and it destroys the fibre.
- Drying is the actual cure. Mildew needs damp, warm, poorly lit, still air. Remove any one of those and it stops.
- Pressure washers wreck most patio furniture. They tear wicker, drive water into wood, and strip finishes.
Mildew is why your furniture looks like that
Before reaching for anything, work out what you are looking at. Dirt sits on the surface and wipes off with a damp cloth. Mildew is embedded, patchy rather than even, usually grey, black, or white, and it has a musty smell. If a damp cloth barely touches it, it is alive.
University of Missouri Extension describes mildew as a thin, black, or sometimes white, growth produced by mold that produces a musty odour and causes discoloration. Their list of what it needs is the useful part, because it doubles as your prevention plan: moisture, certain temperatures, and conditions that are damp, warm, poorly lighted, and where air is not circulated. It especially likes natural fibres such as cotton, linen, wool, and leather.
Read that list again and look at where your cushions spend the winter. Stacked in a corner of a shed, damp from the last rain, no light, no airflow. That is not storage, it is a culture dish. The same reasoning is why how to stop condensation in a shed matters here: a shed that sweats every night will bloom mildew on everything stored in it.
What to use on each material
| Material | Use | Avoid |
|---|---|---|
| Resin wicker | Mild soap, soft brush, hose rinse | Pressure washing, stiff brushes |
| Natural wicker or rattan | Damp cloth, minimal water, dry fast | Soaking, any hosing |
| Teak and hardwood | Mild soap and a soft brush along the grain | Bleach at strength, pressure washing |
| Powder coated aluminium | Mild soap, soft cloth, dry after | Abrasive pads, which open the coating to corrosion |
| Wrought iron | Soap, dry immediately, touch up chips | Leaving it wet, which is rust |
| Plastic and resin | Soap, or diluted bleach for mildew | Solvents, which cloud the surface |
| Cushions and fabric | Soap first; diluted bleach only if the fibre allows | Bleach on wool, silk, or spandex |
The teak question comes up constantly. Teak greys because UV bleaches the surface, not because it is dirty or rotting. That grey is a cosmetic layer a few cells thick and the wood underneath is fine. If you like the silver look, wash it and leave it. If you want the honey colour back, that is a light sand or a teak cleaner, not a scrub.
How do you clean outdoor furniture step by step?
- Dry brush first. Get the loose grit, cobwebs, and leaf litter off before water turns it into mud you then grind into the weave.
- Start with mild soap. Warm water, a squirt of dish soap, a soft bristle brush. This removes ordinary dirt on every material listed above, and on a lot of furniture it is the whole job.
- Work top down and section by section. Do not let soap dry on the surface, especially in sun. Rinse as you go.
- Escalate only for mildew. If patches survive the soap, mix roughly 2 tablespoons of liquid chlorine bleach per quart of warm water, which is the dilution MU Extension gives for fabrics. Test on a hidden spot first, every time.
- Let it dwell, do not scrub it. Bleach kills the growth chemically. Give it a few minutes rather than attacking the surface with a wire brush.
- Rinse properly. Bleach residue left on fabric or metal keeps working on it long after you have walked away.
- Dry it completely, in the sun if you can. This is the step people skip and it is the one that decides whether the mildew comes back next week. Sunlight and moving air are both hostile to it.
- Protect what wants protecting. Touch up chips on wrought iron, oil teak if you want the colour, and check that cushion covers are properly dry inside the foam, not just on the surface.
Two safety rules that are not optional. Never mix bleach with ammonia or any cleaner containing ammonia: the reaction produces toxic gas and people have died from it. And never use chlorine bleach on wool, silk, or spandex, which MU Extension warns against explicitly, because it destroys those fibres rather than cleaning them. Check the care label on cushion covers before anything stronger than soap touches them.
Why not just pressure wash it?
Because most patio furniture is softer than the tool. A pressure washer will strip the finish off powder coated aluminium, blow apart the weave on wicker, drive water deep into hardwood where it swells and cracks, and force water into cushion foam that will then take a fortnight to dry, which is precisely the condition mildew wants.
If you insist, the only defensible use is on solid plastic or resin furniture at genuinely low pressure with a 40 degree tip from a couple of feet back. Everything else gets a brush. The general principle, that surface material dictates pressure rather than the other way round, is the same one running through how to pressure wash a deck and how to pressure wash siding: wood and coatings need far less force than concrete, and furniture needs less again.
Stopping it coming back
Cleaning is a symptom fix. Mildew needs four things, and you only have to remove one of them.
- Bring cushions in, or stand them on edge. A cushion lying flat holds water in the foam for days. On edge it drains and dries.
- Store dry, never damp. Putting a wet cushion into a storage box in October guarantees what you find in April.
- Ventilate the storage. Air movement is on MU Extension’s list of prevention methods for a reason. A sealed box with no airflow is the ideal habitat.
- Let light in. Poorly lit is one of the four conditions. Furniture that sits in permanent shade under a tree will always be the first to bloom.
- Breathable covers, not plastic sheeting. Plastic traps condensation underneath and creates the exact microclimate you are trying to avoid.
- Wash before storing, not after. Organic matter left on the surface over winter is food.
If the furniture is past saving, and waterlogged foam and rotted natural rattan often are, that is worth knowing before you spend a Saturday on it. Our roundup of the best outdoor furniture covers what holds up outdoors, and the best wicker outdoor seating is worth reading if you are replacing natural wicker with resin, which survives weather far better. For cushions specifically, the best outdoor seating with cushions covers the sets with fabrics designed to shed water, and the best outdoor seating with storage solves the where do the cushions live problem directly.
Frequently asked questions
How do you get mildew off outdoor furniture?
Try mild soap and warm water first. For patches that survive, use about 2 tablespoons of liquid chlorine bleach per quart of warm water, let it dwell a few minutes rather than scrubbing, then rinse thoroughly and dry completely. Test a hidden area first, and never use bleach on wool, silk, or spandex.
Can you pressure wash patio furniture?
Generally no. It strips powder coating, breaks up wicker weave, drives water into hardwood and cushion foam, and leaves furniture wetter for longer, which encourages mildew. Solid plastic furniture can take low pressure with a wide 40 degree tip from a couple of feet. Everything else wants a soft brush.
Why does my outdoor furniture keep going mouldy?
Because the conditions have not changed. Mildew needs moisture, warmth, poor light, and still air, and it thrives on natural fibres like cotton and leather. Cleaning removes the growth but not the habitat. Dry cushions properly, store them somewhere ventilated and lit, and stand them on edge rather than flat.
Is bleach safe on outdoor cushions?
On many synthetics, diluted and rinsed, yes. Never on wool, silk, or spandex, which extension guidance warns against directly. Always test a hidden spot, and never mix bleach with ammonia or an ammonia based cleaner, since the combination produces toxic gas. Check the care label before you start.
Should you clean teak furniture that has gone grey?
Only if you dislike the colour. Grey teak is UV bleaching of the outermost surface, not damage or rot, and the wood beneath is unaffected. Wash it with mild soap to remove dirt and mildew and leave the silver patina, or use a teak cleaner and light sanding if you want the original honey tone back.
How should you store patio cushions over winter?
Clean them, dry them completely including the foam inside, then store somewhere ventilated rather than sealed. Air circulation is a documented mildew prevention measure. Avoid plastic sheeting, which traps condensation, and avoid a damp unventilated shed, which is exactly the warm, dark, still environment mildew needs.
Final thoughts
Cleaning outdoor furniture is mostly restraint. Identify whether it is dirt or mildew, start with soap, escalate to diluted bleach only where the material allows, never mix it with ammonia, and put the effort into drying rather than scrubbing. Then fix the storage, because mildew is a habitat problem and the habitat is usually a damp cushion in a dark corner. If the furniture itself has given up, the best outdoor furniture guide covers what actually survives a winter outside.