Trisodium phosphate, or TSP, is a common deck cleaner. The chemical is strong enough to remove dirt and grease from the surface of your deck, but will not harm your plants or lawn when you rinse the deck. Cleaning your deck with TSP is a less expensive alternative to power washing or hiring a professional deck-cleaning company. You can clean your deck with TSP in one day.
Sweep the deck thoroughly with a broom. Unplug any electrical appliances on the deck and move them inside or onto the lawn. Turn off the power to any electrical outlets on the deck at the breaker box.
Cover your deck plants with a plastic tarp. The TSP won't harm the plants, but the pressure from the garden hose might damage the foliage.
Put on protective gloves. Fill a bucket with 1 gallon of water and add 1 cup of TSP and agitate the water with a stiff-bristle brush.
Scrub the surface of the deck with the stiff-bristle brush and TSP solution. Scrub in the direction of the grain of the wood planks. Dip your brush back into the TSP solution after each plank.
Rinse the entire deck surface with fresh water from a garden hose.