As an Amazon Associate, Decks.com earns from qualifying purchases from the links in this post.
Removing Moss & Algae from Your Deck
![Moss](/media/z3uoujhh/moss-feature-photo.png?width=500&height=333.33333333333337&format=webp)
Moss and algae growth can be detrimental to the integrity of your deck if left untreated. It can also be slippery in damp conditions. And because moss and algae can spread and multiply very quickly, it’s vital to get rid of it at the first sign of growth.
The main catalyst of moss and algae growth is the accumulation of leaves and debris on your deck, which will build up and retain moisture, especially after storms and inclement weather. This trapped moisture begins to spawn mold, mildew, moss, and algae – and the damper and darker the environment – for example, if your deck has natural shade or cover from trees – the more fertile the breeding ground.
If left untreated, your deck will not only look unsightly, it could pose a slipping hazard for your family and guests. Just as bad, that retained moisture will slowly begin to penetrate into the wood, causing cracks, splinters and ultimately, wood rot. And while less prone to wood rot, composite decking isn’t immune to the hazards of moss and algae; it can be as slippery and dangerous as a wood deck if moss and algae are left unchecked.
As the saying goes, an ounce of prevention is worth a pound of cure. Don’t let debris build up on your deck in the first place. Keep it swept clean and make a point to regularly clear out any debris from cracks or gaps. Keep the surface as dry and openly exposed as possible to prevent moisture retention, bacterial growth and more.
Steps for Cleaning Moss & Algae from Your Deck
Cleaning your deck annually will help prevent moss and algae growth while increasing its longevity, in general. You can use a commercially available deck cleaner, such as #1 Deck Wood Cleaner, or you can easily create your own with a few simple household items that you probably already have.
Here’s a quick step-by-step guide for how to remove moss and green algae from a wood deck:
Step 1: Make your cleaning solution
Fill a bucket with one gallon of warm water and ¾ cup of chlorine bleach. You can also add ⅓ cup of powdered, ammonia-free laundry detergent for extra cleaning strength.
Step 2: Apply the solution
After the solution has been mixed, pour it onto your deck and allow it to sit for 10-15 minutes.
Step 3: Scrub
Next, thoroughly scrub the deck to remove all the moss and algae. We recommend using a scrub brush attached to a pole or broom handle, however, a hand brush can also be used (the latter will make for a more labor-intensive process).
Step 4: Rinse
Finally, rinse the deck surface with a garden hose to remove any lingering residue and allow the deck to dry completely.
You may also opt to use a power or pressure washer to save time and labor. It’s best to use a fanning nozzle, which will safely and effectively clean the algae and moss from your deck without damaging the wood or removing paint or stain. You can use the same detergent recipe described above, but may want to tweak proportions to ⅓ cup of powdered laundry detergent (ammonia-free), 1-quart of bleach and 3 gallons of water, depending on your washer’s capacity.
This page contains affiliate links. If you choose to purchase after clicking a link, Decks.com may receive a commission at no extra cost to you.
Can You Paint or Stain Composite Decking?
Most composites don’t require painting or staining. However, if you are considering staining or painting your deck, you can learn how to do so and what you’ll need at Decks.com.
What is Dry Rot and How Can You Prevent Your Deck From Rotting?
Dry rot is a serious problem for wood decks because it compromises its structural integrity. Learn the signs and causes for deck rotting, as well as how to prevent or fix it, at Decks.com.
Capped Composite Decking
What is capped composite decking? It's a great option if you like the look of wood but not the maintenance. Learn about capped composite at Decks.com.
Pressure Treated Wood: Types, Grading Standards & More
Wondering if pressure treated wood is right for your project? Learn more about the different types of pressure treated lumber as well as how long they last at Decks.com.
Pool Decking Options
When choosing a pool deck material, you should consider slip-resistance, heat absorption and more. Find the best material for your pool deck with Decks.com.
More Helpful Resources
Explore Articles by Topic
![Footings](/media/3vsas025/all-articles_footings-2x.png?format=webpg&quality=80)
Footings
Information related to installing frost footings for decks
![Framing](/media/5wrarsgy/all-articles_framing-2x.png?format=webpg&quality=80)
Framing
Learn structural framing methods
![Decking](/media/meljt4np/all-articles_decking-2x.png?format=webpg&quality=80)
Decking
Learn about wood and composite decking materials
![Stairs](/media/2sopl0br/all-articles_stairs-2x.png?format=webpg&quality=80)
Stairs
An in-depth look at the complex issue of how to build stairs
![Railings](/media/hpwbuyzr/all-articles_railings-2x.png?format=webpg&quality=80)
Railings
How to install guardrails and handrails to meet IRC code
![Features](/media/tvcahlmk/all-articles_features-2x.png?format=webpg&quality=80)
Features
An overview on water drainage, benches, planters and lights
![Design](/media/3bvpzvtz/all-articles_design-2x.png?format=webpg&quality=80)
Design
The basics of deck design
![Planning](/media/qdenqrqv/all-articles_planning-2x.png?format=webpg&quality=80)
Planning
Learn about permits and working with contractors
![Porches and Patios](/media/sg5bst1z/all-articles_porches-and-patios-2x.png?format=webpg&quality=80)
Porches & Patios
Build a covered deck to enjoy all seasons
![Ledger](/media/0htjl4uu/all-articles_ledger-2x.png?format=webpg&quality=80)
Ledger
Proper attachment techniques
![Care](/media/qdpnwkry/all-articles_care-2x.png?format=webpg&quality=80)
Care
Maintain your deck to maintain your investment
![Materials](/media/zqfflkeo/all-articles_materials-2x.png?format=webpg&quality=80)
Materials
An overview on water drainage, benches, planters and lights
How to Remove Scuffs and Scratches from Composite Decking
Removing scuffs and scratches can help make your composite deck look like new. Learn how to fix and prevent your composite deck from future scratches.
How to Prepare & Protect Your Deck for Winter
Preparing and protecting your deck for the cold weather is important to ensure the longevity of your deck, especially in cold climates. Learn how to prepare your deck for winter at Decks.com.
Average Cost to Stain a Deck
Find the national average costs for staining and sealing a deck per square foot, including sanding and power washing prices. Learn more at Decks.com
Fence Post Spacing: How Far Apart Should Fence Posts Be?
Spending a little more time and effort up front on determining the best fence post spacing for your deck project, could save you a bunch of time and money when it comes time to build it. Here’s how to do it…
Eco Friendly Composite & Wood Decking Options
Looking for the most environmentally friendly way to add a gorgeous deck to your home? Learn how composite decking is made from recycled materials at Decks.com.
Composite vs Wood
Composite and wood decking differ in terms of maintenance, costs, labor, and lifetime value. Compare composite vs wood decking at Decks.com.
Explore Articles by Topic
![Footings](/media/3vsas025/all-articles_footings-2x.png?format=webpg&quality=80)
Footings
Information related to installing frost footings for decks
![Framing](/media/5wrarsgy/all-articles_framing-2x.png?format=webpg&quality=80)
Framing
Learn structural framing methods
![Decking](/media/meljt4np/all-articles_decking-2x.png?format=webpg&quality=80)
Decking
Learn about wood and composite decking materials
![Stairs](/media/2sopl0br/all-articles_stairs-2x.png?format=webpg&quality=80)
Stairs
An in-depth look at the complex issue of how to build stairs
![Railings](/media/hpwbuyzr/all-articles_railings-2x.png?format=webpg&quality=80)
Railings
How to install guardrails and handrails to meet IRC code
![Features](/media/tvcahlmk/all-articles_features-2x.png?format=webpg&quality=80)
Features
An overview on water drainage, benches, planters and lights
![Design](/media/3bvpzvtz/all-articles_design-2x.png?format=webpg&quality=80)
Design
The basics of deck design
![Planning](/media/qdenqrqv/all-articles_planning-2x.png?format=webpg&quality=80)
Planning
Learn about permits and working with contractors
![Porches and Patios](/media/sg5bst1z/all-articles_porches-and-patios-2x.png?format=webpg&quality=80)
Porches & Patios
Build a covered deck to enjoy all seasons
![Ledger](/media/0htjl4uu/all-articles_ledger-2x.png?format=webpg&quality=80)
Ledger
Proper attachment techniques
![Care](/media/qdpnwkry/all-articles_care-2x.png?format=webpg&quality=80)
Care
Maintain your deck to maintain your investment
![Materials](/media/zqfflkeo/all-articles_materials-2x.png?format=webpg&quality=80)
Materials
An overview on water drainage, benches, planters and lights