After the leaves have fallen on and around your deck, consider giving your composite wood deck or pressure treated deck a thorough cleaning, especially in colder climates where snow could deter your decision to maintain your decking and outdoor living area. Cleaning your deck late in the year is always a good idea as it helps prevent the buildup of mold and mildew on the deck surface. By making sure all leaves and debris are swept off the deck surface before snow accumulates, your spring cleaning will be much easier.
It's important to clean bird droppings and common spills that happen throughout the deck season. You don't want these cleanable mishaps to turn into stains on your composite or lumber deck because they remained on the surface too long.
Scrub and rinse your deck
Start cleaning your composite decking or pressure treated decking by scrubbing the surface with soapy water. Start at the top of the deck railings and work your way down to the deck surface. It's necessary to remove the dirt and debris that accumulates on the composite deck surface. This will also prevent the build-up of pollen that can cause mold and mildew growth. Pressure washers should only be used at lower pressures to wet and rinse synthetic decking and railing. For ground-in soil you'll need to apply a detergent, scrub the deck surface with a course bristle brush and rinse thoroughly with water.
Apply a quality deck cleaner to the surface
Deck cleaners usually contain sodium percarbonate and a detergent, which is effective on normal dirt and grime and helps bleach out mold and mildew stains. Oxalic acid cleaners are effective on rust stains from metal patio furniture.