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Ask Dr. Laundry

Ask Dr. Laundry

Mildew on Outdoor Furniture

By Dr. Laundry November 7, 2011

Q:  What should I use to clean mildew from the cushions on our porch chaise lounge. The cushions are made of heavy duty cloth.

A:  I can recommend a bleach solution, but in addition to removing the mildew it could also alter the color of the cushions depending on the fabric.  The best thing to do is a quick bleach-ability test:  add 2 teaspoons Clorox® Regular-Bleach to 1/4 cup water and apply a drop of this solution to a less visible part of the cushion.  Wait 1 minute and then blot dry. No color change means you can safely bleach the cushion, and I would proceed as follows:

1.  For a removable cushion cover:  take off the cover and zip it closed.  If the mildew is severe, let the cover soak in a solution of 1/4 cup Clorox® Regular-Bleach per gallon of water for 5 minutes, making sure it is fully submerged.  Wash in hot water using detergent plus 3/4 cup Clorox® Regular-Bleach.  Do not place the cover in your dryer. If after washing you have made some progress, then repeat the treatment.  When washing is complete, you will need to put the cover back onto the cushion before it dries, otherwise the cover may not fit! 

2.  For a non-removable cushion cover that has a water-repellant finish:  working outside, wipe the cushion down with a bleach solution of 3/4 cup Clorox® Regular-Bleach per gallon of water. Reapply the bleach solution as necessary to keep it wet for 5 minutes, then rinse thoroughly using a garden hose.  Be sure to also water any plants near the area you are working before and after you wash the cushions.  Let the cushions air dry in a warm, dry place.

3.  For a non-removable cushion that easily absorbs water:  take it to a launder-mat that has extra-large washers that can handle a bulky item.  Assuming the cushion fabric passed the bleach test, wash the cushion in hot water using detergent + 3/4 cup Clorox® Regular-Bleach.  Repeat the treatment if the mildew is severe and do not place the cushions in the dryer.

If the fabric is not bleachable, it will be more difficult to remove the mildew since the best mold and mildew removers contain sodium hypochlorite (like Clorox® Regular-Bleach).  You could try several washes in hot water using an oxygen bleach (like Clorox2®) and letting the cushions air dry in the sun. 

Anyone else have mildew on their outdoor furniture?