Start with the material your cover is made from

The first step is checking what your cover is actually made of, because the cleaning method changes based on the fabric. Most patio furniture covers are polyester, vinyl, or canvas — and each one handles water and soap differently. Look at the tag sewn into the cover or check the manufacturer's website if you still have the receipt. If you cannot find that information, polyester is the safest bet for most covers sold in the last ten years.

Polyester covers can handle a scrub brush and mild detergent. Vinyl covers need gentler treatment — a soft cloth and the same detergent, but no stiff brushing. Canvas covers are durable but can absorb water, so they need to dry completely after cleaning or mildew will grow inside. The difference matters because using a stiff brush on vinyl will wear through the protective coating, and skipping the dry step on canvas means you are storing mildew in your garage.

Key Takeaways

  • Check the cover's material tag first — polyester, vinyl, and canvas each need different cleaning methods and drying times.
  • A mixture of one part mild dish soap to five parts water works for all three materials and removes dirt without damaging the fabric.
  • Scrub polyester covers with a soft-bristled brush, wipe vinyl covers with a cloth, and use a brush gently on canvas to avoid pushing water into the weave.
  • Let the cover dry completely in the sun or in a well-ventilated space before storing it, or mildew will develop inside the folds.
  • Hose off loose dirt before you start washing — this cuts the scrubbing time and prevents you from grinding grit into the fabric.

Rinse off loose dirt first with a garden hose

Before you explore any soap, spray the cover with a garden hose on low or medium pressure to remove leaves, dust, and loose debris. This step saves you time because you will not be scrubbing dirt into the fabric, and it means your soapy water stays cleaner longer. Spray from a distance of about three feet and move the hose across the entire surface, including the underside if the cover is draped over furniture.

Do not use high pressure — that can push water into seams and under the protective coating. If the cover is very dirty or has been sitting all season, let it sit for five minutes after the initial rinse. The moisture will loosen stubborn dirt and make the next step easier.

Mix a cleaning solution and scrub the surface

Combine one part mild dish soap (like Dawn or store-brand equivalent) with five parts water in a bucket. This ratio is weak enough not to damage any of the three common cover materials, but strong enough to cut through grime and mildew stains. Avoid bleach, which can weaken polyester and vinyl over time, and skip the pressure washer — the force will damage the fabric and the seams.

For polyester covers, use a soft-bristled brush — the kind you would use on a car — and scrub in circular motions. For vinyl covers, use a soft cloth or sponge instead; a brush will scratch the coating. For canvas, use a soft brush but explore light pressure and work in one direction rather than scrubbing hard, because canvas weaves can trap water if you push too hard. Pay extra attention to seams, corners, and any areas where mildew or mold is visible — these spots need a few extra passes.

Rinse thoroughly with clean water

Once you have scrubbed the entire cover, rinse it again with the garden hose using low pressure. Spray until the water running off is clear and you no longer see soap bubbles. Soap left on the cover will attract dirt and can break down the fabric over time, so this step is not optional. If the cover is very soapy, you may need two or three passes with the hose.

For vinyl and polyester covers, you can wring out excess water gently with your hands or a soft cloth. For canvas, do not wring — instead, let it drip dry for a few minutes before moving it.

Dry the cover completely before storing

Hang the cover in direct sunlight or in a well-ventilated space like a garage with the door open. The sun is the fastest and best option because UV light also kills mildew spores. If you are hanging it outdoors, use a clothesline or drape it over a railing so air can circulate on both sides. Do not fold it up while it is still damp — even slightly damp covers will develop mildew inside the folds within a few days.

Drying time depends on humidity and temperature. In dry weather, most covers dry in four to eight hours. In humid conditions, it may take a full day or longer. If you are storing the cover indoors, make sure it is bone dry before you fold it and put it away. A moisture meter (available at hardware stores for under twenty dollars) can tell you if the fabric is truly dry, but the straightforward test is to touch the inside of the cover — if it feels cool or damp, it needs more time.

Treat mildew stains before they spread

If your cover has black or green spots that do not come off with soap and water, you have mildew. Spray the affected area with a solution of one part white vinegar to three parts water, let it sit for ten minutes, then scrub gently with a soft brush. Rinse thoroughly and dry completely. Vinegar is safer than bleach for most cover materials and works well on mildew.

If the mildew is extensive or the cover smells musty even after cleaning, the damage may be permanent. Mildew that has grown deep into canvas or polyester can weaken the fibers and is difficult to remove completely. In that case, replacing the cover is often cheaper than trying to save it, especially if the cover is more than five years old.

Store the cover properly to prevent mildew next season

Once the cover is completely dry, fold it loosely and store it in a cool, dry place — not a damp basement or an uninsulated garage where temperature swings can cause condensation. A plastic storage bin with a lid works well if you add a desiccant packet (the kind that comes in vitamin bottles or shoe boxes) to absorb any moisture. Do not store the cover in a sealed plastic bag without ventilation, because trapped moisture will cause mildew to grow.

If you live in a humid climate, consider storing the cover indoors during the off-season rather than in an outdoor shed. Check on it once a month during storage — if you see any sign of moisture or smell, take it out and dry it again. Proper storage prevents you from having to deep-clean the cover every season.

Frequently Asked Questions

Can I use a pressure washer to clean patio furniture covers?

No. Pressure washers force water into seams and under the protective coating of vinyl and polyester covers, which causes leaks and breakdown of the material. A garden hose on low pressure and a soft brush are all you need.

What if my cover has mold that smells bad even after cleaning?

Mold that has grown deep into the fabric is difficult to remove completely and can weaken the material. If the cover is more than five years old or the smell persists after vinegar treatment and drying, replacing it is usually the better choice than trying to save it.

How often should I clean my patio furniture covers?

Clean covers once a season before storage, or more often if you live in a humid or dusty area. A quick rinse with the hose every month during use keeps dirt from building up and makes the seasonal deep clean faster.

Can I use bleach to remove mildew stains?

Bleach can weaken polyester and vinyl over time and may cause discoloration. White vinegar mixed with water is safer and works just as well on mildew. Spray it on, wait ten minutes, scrub gently, and rinse thoroughly.

What is the best way to dry a canvas cover?

Hang it in direct sunlight or a well-ventilated space without folding it. Canvas absorbs water, so it needs more drying time than polyester or vinyl — usually a full day in humid conditions. Do not store it until it is completely dry or mildew will grow inside.