5 Simple Deck Wash Recipes: General Maintenance & Mildew

Wood decks are a nice feature for the back yard but they do require a bit of TLC to keep them looking as good as possible. They can be expensive to build and replace, so it’s smart to want to extend their lifespan as long as possible.

Here are a handful of homemade cleaners you can try including a couple for removing stains and mildew.

First A Few Tips:

  • Use a nylon bristle brush or broom for good scrubbing power.
  • Check a test area first before applying soaps and chemicals to ensure that no damage or discoloration occurs. The type of wood (and the condition it’s in), the type of stain or paint can each respond differently to a treatment.
  • A simple garden hose with a spray nozzle attachment can be used if you don’t have a power washer, though you will need to put a bit more elbow grease into the job. Check your local hardware store for a “fireman” nozzle to amp up the muscle.
  • Don’t forget to do the steps and the rails!
  • Cover prized bushes and landscaping with sheets of plastic to protect from splashes/overspray.

Using A Pressure Washer:

  • These can work well if used correctly and the wood is in good shape (the pressure can cause further damage if it isn’t). Keep it on the lowest setting that will clean the surface without damage (this will depend on how soft the lumber is).
  • You should be able to start safely at a 500 psi setting and work up from there.
  • Select a fan tip setting between 40′ and 60′ tip size and spray with the grain.
  • I found a page of expert tips for using a pressure washer here: Decks.com.

Quick Directions For Cleaning:

  • Spray surface with water first before applying wash recipe, this helps prepare the deck so the solution can work its magic.
  • For ingredient temperature, use quite warm but not so hot that you can’t rest your hand in it.
  • Rinse area well when removing cleaner.
  • Do not let the solution dry before you take it off (you can lightly spritz with water during waiting period if it’s drying too quickly).

DIY Recipes:

General All-Purpose:

1 gallon water
1 C. powdered laundry detergent (no bleach)
3/4 C. oxygen bleach (optional but good to use if mildew stains are present)

  • Directions: Combine well then pour over surface. Scrub lightly with a broom or brush. Leave for 5 to 10 minutes then scour again. Rinse. Repeat if needed.

Homemade Maintenance Spray:

Use this mix for a light jobs where no real problems or staining exists (basically just removing dirt and freshening up the deck).

Combine 1 gallon of water with one of the following:

  • 2 cups white household vinegar. Pour over area, leave for 10 to 15 minutes then brush with a stiff broom. Hose off.
  • You can also try: 3/4 cup oxygen bleach.
  • Or this one: 1 cup powdered laundry detergent.

Heavy Duty Batch:

  • 3 quarts of water, 1 C. oxygen bleach and 1 C. of TSP. Mix well and pour over surface, scour with a stiff bristle broom. Leave for about 10 minutes before scrubbing again. Hose off.

Fighting Mildew:

  • Try a mix of 3 quarts water, 1 C. oxygen bleach and 3/4 C. of liquid dishwasher detergent. Apply to surface, brush with a stiff broom and leave for 10 to 15 minutes. Scour then hose off.

Stain Remover (such as Mold and Rust):

  • Mix 1 tablespoon of oxalic acid crystals (wood bleach) with 1 gallon of water. Apply to trouble spots with a brush and leave alone until discoloration has faded then rinse well.
  • Grease spots can be conquered by applying powdered laundry detergent directly onto the area (use a nylon bristle broom), let it set for a few minutes then rinse.

General Care/Tips:

  • After cleaning and before moving furniture back, inspect all boards for loose nails, splintering edges or rough spots other miscellaneous damage. Do sanding and repairs where necessary.
  • Keep natural debris from gathering into piles such as leaves, branches, etc., to avoid sitting puddles/dampness.
  • Avoid using mats consisting of natural fibers (ie. jute) since these hold moisture which can then attract mildew.
  • Occasionally move furniture and accessories around (such as planters) to prevent discoloration.

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    • andrew gibson

    All great recipes . I want to find a wood / deck cleaner that is flower and tree friendly. Maybe major flushing after the cleaning ..Thanks- Andrew with a 100 year old cedar porch

    • Marta R.

    Wow! Today I used the general cleaner. I used 2 cups of Tide powder, 1-1/2 cups Oxiclean with 2 gallons of water. It was amazing. Cleaned the whole deck and also our resin table and chairs. The table and chairs sparkled afterward. And the deck looks great. A deck brush attached to a broom handle is a must! Made the job so easy. Followed given instructions to let sit 5- 10 min, scrub again and rinse.
    This will be the only cleaner I need for outdoor stuff. It also cleaned up some of my garden statues nicely. Haven’t tried it on any painted statues yet, but plan to tomorrow.

      • Carrie

      Warning – It’s a good thing I spot-tested first! I tried the maintenance mix using OxiClean & water… and it completely removed the finish and left wood fiber “fuzzies”! (It’s a 3-year old cedar deck with Wolman’s F&P oil-based sealer applied a year ago.) It wasn’t from being too vigorous – I used a super soft broom, and even a few places where I accidentally dripped the Oxi wound up discolored and fuzzy. Maybe the OxiClean has some other ingredient that makes it too powerful? After that, we were too afraid to use any cleaner at all. So we just sprayed it with the garden hose on full power and brushed it with the soft broom, and then rinsed it. It took off most of the dirt without removing any finish. Bottom line: I’d look for 100% oxygen bleach, not OxiClean.

    • eileen

    Thks for info…what is tsp that is called for in the heavy duty cleaner?

      • karen

      tri sodium phosphate…..you find it in the paint area of your hardware store…it is used for prepping your walls before painting.

      • Anne Ormond


    • Kathy Lockard

    in the heavy duty mix, what is TSP??

      • Jim

      Tri Sodium Phosphate. You can find it at any hardware store. It is often used to prepare walls for painting.

    • Beverly

    Will the deck cleaners also work on synthetic deck products?

    • Sue Berger

    Does the run off hurt the grass and flower?

    • Joyce Wall

    Never heard of oxygen bleach and wood bleach., where can I purchase these items?
    I have a mobile home with plants surrounding it. I have to pressure wash it at least once a year and am concerned for the foliage I have around it. Will those items harm them?

    • william

    What will remove deck stain sufficiently?

    • paula nadels

    can I use your recepes safely beside our pond (with frogs and salamanders)?

    • Russell Collins

    Good to see someone putting out decent info without trying to push their own “WONDERFUL PRODUCT” keep it up!

    • Mary Howes

    How can I clean a cedar deck without damaging the stain?

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