This is a comprehensive list of healthier alternatives to bleach and toxic deck cleaning formulas that still work to get your deck clean even if it’s covered in mold, stains, and debris.
I cover deck and outdoor furniture cleaners that are safe for you, your kids, your pets, and your plants.
Some are simple DIY natural recipes and others are ready to use soaps that are eco-friendly (and biodegradable).
I list which options are appropriate for wood decks, painted decks, composite decks, and vinyl decks.
The same solutions that work on decks also work on fences, siding, and outdoor furniture.
This post contains affiliate links. Upon purchase, I earn a small commission at no extra cost to you.
Oxygen bleach works well to clean decks. The usual recommendation is to use the brand OxyClean, but an all-natural alternative (without acrylic polymers, dyes, fragrance, or unknown surfactants) is Nellie’s Oxygen Brightener Powder.
Oxygen bleach products are safe for the environment (unlike bleach and some other cleaning products). Nellie’s powder is biodegradable and doesn’t harm plants or pets.
Performance: This does work on algae and mold. It might not get rid of deep-seated mold and algae in wooden decks, but it does work well on surface-level growth and it prevents mildew and algae build-up if it’s used often.
It also works on dirt build-up, rust, and other stains. It doesn’t bleach wood but it does help to reduce the graying out of wood, restoring some of its original color.
Use on: Most wood decks and composite decks. (Not for use on wooden decks finished with linseed or tung oil).
DIYRecipes:
Without Soap: Dissolve 1 cup of Nellie’s Powder in 1 gallon of water. Apply this to the deck and scrub.
With Soap: In 2 gallons of warm water, dissolve 2 cups of Nellie’s all-natural oxygen bleach. Add 1/4 cup of a natural, biodegradable liquid dish soap. (This dish soap is plant safe)
With Soap & Alcohol: Add 2 tablespoons of natural dish soap, to 1 gallon of water, with 1 pint of rubbing alcohol, and 1 quart of oxygen bleach.
Note: A specialized deck scrub brush that gets into the grooves between boards works best to clean decks.
i. Borax (sodium borate), another bleach alternative, is a highly effective homemade cleanser, degreaser, stain remover, and anti-mildew cleaner.
Performance: It works to remove algae, moss, mold, and mildew. It also helps slow down the return of algae and mold.
Use on: Wood decks, siding, and roofing. It works on stone patios or other exterior stone, concrete brick, and slate (like pavers). Not ideal on painted surfaces.
DIY Recipe:
Mix one cup of borax into one gallon of water and scrub the surface with a deck brush.
ii. TSP (trisodium phosphate), is another DIY powdered cleaning product that really works well at killing mold and mildew.
And although the substance is biodegradable and does not give off VOCs it does require some skin and eye protection and the phosphate does throw off the natural balance of the environmental biome. You should use it with caution especially around plants you want to keep alive or around streams, ponds or lakes.
You could use it occasionally if you really let the algae and mold go on for too long or if you don’t have precious plants nearby. To avoid having to use TSP, use the other options on this list more regularly.
Use on: Wooden decks. Not for use on painted wood like paint decks, fencing, or outdoor furniture, unless you want to remove the paint.
DIYRecipe:
Dissolve 1/2 cup of TSP in 2 gallons of warm water. For mold and mildew, you can mix 1 cup of TSP with 3 quarts of warm water. The solution can be used in a spray bottle or applied with a stiff scrub brush or sponge. Rinse thoroughly with plain water.
i. ECOS dish soap is a top pick for a non-toxic biodegradable soap. It works well on all types of decks, fences, and outdoor furniture. It’s pet-friendly and doesn’t harm plants.
They have scented and fragrance-free versions.
It can be used alone or in a formula with vinegar and/or baking soda, or oxygen bleach.
iii. RMC Exterior Soap is an exterior soap to clean and nourish oil-treated exterior wood.
Use on: To clean external wooden surfaces, which have been treated with linseed oil (like Rubio Monocoat Exterior Hybrid) and Tung Oil.
Directions:
Mop the patio, shake the bottle, pour 1 liter of RMC Exterior Soap into 3 liters of clean water. Clean with a floor cloth or fluff-free duster. Allow the surface to dry for approx 30 minutes.
4. DIY Recipe for Composite Decks: Vinegar and/or Baking Soda
White vinegar is a degreaser and has some anti-mold and mildew properties. You can use natural white vinegar or organic apple cider vinegar as a deck wash.
Baking soda acts as a wood brightener on weathered wood and is a good all-purpose cleaner.
Baking soda is plant safe, the dish soap below is plant safe, but vinegar can harm plants in high concentrations.
Use on: Wood decks, composite decks like Trex. Vinegar is not to be used on painted decks or decks finished with linseed or tung oil.
DIY Recipes:
Just Vinegar: 1 part water and 1 part vinegar and spray onto your deck.
Vinegar & Soap: Add a teaspoon of natural liquid dish soap to 2 gallons of the vinegar/water solution.
Vinegar & Baking Soda: Add 1 cup vinegar with 1 gallon of water. Sprinkle the baking soda on the wood and then add the vinegar and warm water and scrub.
Vinegar, Baking Soda & Soap: Add 1 cup of vinegar and 2 tablespoons of natural dish soap to 1 gallon of water. Add one box of baking soda to the affected areas of the deck. Then add the vinegar, soap, and water solution to the deck, one section at a time. Scrub!
Just Baking Soda: Add 1 cup of baking soda to 1 gallon of water. Stir until dissolved. Brush onto the deck and scrub. Rinse after.
You can also add 1/2 cup of lemon juice to 1 gallon of water with baking soda and vinegar.
5. Brighten Wood, Remove Stains & Restore Color Naturally
i. Oxalic acid, an organic compound found in plants, works to remove iron stains and tannin stains that are common with cedar and redwood decks.
Oxalic acid used as a deck wash helps to remove the graying of the wood and restore its color. It does have a bleaching effect on the wood.
It’s biodegradable and won’t kill your grass or nearby plants (it’s not easily absorbed by other plants), but especially in concentrated form and in powder form, you do want to be careful not to breathe it in, or get it on your eyes or mouth.
ii. RMC Exterior Wood Cleaner is a product to remove the gray color and restore the wood to its natural color. It also removes green deposits and regular old dirt. This is used before sealing (or resealing) a deck.
This is an excellent product and folks report it working really well.
Directions:
Dampen the surface with water using a hose, apply Exterior Wood Cleaner using a wide brush or similar. For light cleaning, the product can be diluted with water at a ratio of 1:2. Scrub the treated area. Repeat if necessary. Rinse. Let it dry before treating it with the Exterior Hybrid Linseed oil.
First, rinse the wood deck with water to soften the wood. For tough stains, use a stiff bristle brush with your cleaning solution to remove the dirt, mold, or algae. Avoid power washing that can splinter wood unless you are experienced with this. If you are re-sealing make sure your deck is dry first (give it 24-48 hours).
Some wood deck cleaners can be too harsh for composite decks. Brightening ingredients can strip the sheen, dulling it.
The best eco-friendly composite deck cleaner is soap, water, and vinegar. Baking soda can be used for mold. A gentle pressure power washer can be used up to 3100 psi or a soft bristle brush.
Harsh cleaners can damage the paint, dull the sheen, or lead to cracking and peeling. A gentle soap/surfactant that is free of ammonia works well on painted decks and porches (as well as outdoor furniture).
Not Recommended: Ammonia, vinegar, TSP, or borax could damage a painted deck or other painted outdoor wood in higher concentrations.
Deck Cleaners for a Vinyl Deck
Many companies recommend Cascade Powdered Dishwasher Detergent as a good household option, but this is not the healthiest choice for people or the environment. Some more options below.
Recommended: Natural dish soap and water, Cascade Powdered Dishwasher Detergent is recommended by a couple of companies but a more natural and environmentally friendly alternative is Nellie’s Dishwasher Powder. You can also use Simple Green or AFM Super Clean.
Ammonia mixed can be used against mildew and leaf stains. Not the most eco-friendly option though!
Not Recommended: Bleaching ingredients, no-rinse formulas, abrasive cleaning products like powdered abrasives, scrubbing pads, steel wool.
Composite deck cleaners such as Corte Clean, Thompson’s Water Seal-Oxy Action, Olympic Deck Cleaner, or other powder or liquid composite deck cleaners should not be used with vinyl decks according to the company that makes AZEK Decks.
Corinne Segura is a Building Biologist Practitioner with 8 years of experience helping others create healthy homes.
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