How do I clean mildew off of composite wood benches?

You know that moment when you step into your garden, coffee in hand, ready to enjoy a quiet morning—only to find your beloved composite wood bench looking like it’s sprouted a fuzzy green sweater? Yes, mildew. It’s an uninvited guest that creeps in after rain showers and humid nights, clinging to the surface like it owns the place. But don’t worry—I’ve become a bit of a mildew whisperer over the years, and I’m here to share exactly how I clean it off.

First, I never reach for harsh chemicals. My composite bench is a gentle soul—too much bleach or ammonia can make it change color or lose its smooth finish. Instead, I mix a simple, non-scratch solution: one part white vinegar to three parts warm water in a spray bottle. Vinegar is my hero here—it’s acidic enough to break down mildew’s grip without bullying the material. I give the bench a good spray, letting the mixture soak for about ten minutes. You’ll see the mildew start to panic and lift.

Next comes the scrubbing. I use a soft-bristled brush—nothing metallic, please—and work in gentle circular motions. The key is to be patient, not aggressive. If the mildew is stubborn (the kind that seems to mock me), I sprinkle a little baking soda onto the wet surface and scrub again. The fizzing action helps dislodge the deep-down spores. After that, I rinse the bench thoroughly with a garden hose, making sure no vinegar residue stays behind, because I want the wood to breathe again.

Here’s my secret: after cleaning, I dry the bench with an old towel. Sun-drying is fine, but wiping it prevents new mildew from thinking, “Oh, a damp spot! Let’s settle here.” Finally, I apply a thin coat of composite-safe sealant—just once a year—to keep moisture from partying on the surface.

Now my bench looks like it did on day one: smooth, gray-brown, and ready for my afternoon naps. Mildew still tries to visit, but I just give it the vinegar treatment and send it packing. Your bench will thank you—and so will your morning coffee.