How to Remove Leaf Stains from a Wood Deck
As autumn turns to winter, and the weather cools, trees respond by shedding their leaves by the thousands. Now, most homeowners know the importance of clearing leaves from lawns, driveways and gutters, but it’s equally important to remove leaves from wood decks, and here’s why: As leaves, pine needles, acorns and other types of tree-canopy debris accumulate on the deck, the matted mass will begin to decompose and leach acidic tannins, which will stain the wood with gray and black spots, streaks and silhouettes.
So, the first step in preventing staining is to be proactive: remove leaves as soon as they begin to collect on the deck using a push broom, leaf blower or mulching yard vacuum. And continue to clear away the leaves throughout the fall and early-winter. If you wait until all the leaves have fallen and the trees are bare, it might be too late and the deck may be stained.
Okay, so let’s say your deck is already stained by decomposing leaves, now what?
Well, first be aware that some leaf stains can be stubbornly difficult to remove, so you may need to try a few different cleaning methods. And the condition of the deck plays a key role in how easily stains can be removed. For example, if the deck has been recently stained and sealed or if the finish is in excellent shape, then leaf stains may clean off relatively easily. But, if the deck boards have a badly weathered finish or if they’re severely checked (covered with long, hairline cracks), then the surface will be more porous and the stains will be harder to remove.
Below is a list of five DIY ways to clean leaf stains off wooden decks. However, to prevent damaging the deck, always start with the simplest, gentlest method. If that doesn’t work, move on to the next, slightly more aggressive cleaning technique. And, although composite and PVC decking are much less porous than wood decking, they, too, can be stained by leaves. Before trying any of the stain-removing methods outlined here, check with the decking manufacturer for proper cleaning instructions. And be sure to wear rubber gloves and eye goggles when using any cleaning solution.
1. Scrub with Soap and Water
If the leaf stains aren’t set too deeply into the deck’s surface, you can usually remove them with a good soapy scrubbing. Start by pouring one cup of liquid dish soap or laundry detergent into a two-gallon bucket of warm water. Mix well, then pour the mixture onto the stained deck. Allow it to soak into the wood for about 15 minutes. If the cleaning solution is absorbed into the deck, or if it evaporates in the sun, add more. It’s important to keep the surface wet for at least 15 minutes. Next, use a long-handled, stiff-bristle brush to scrub away the leaf stains. If the stains are lighter, but still remain, rewet the surface and wait another 15 minutes or so. If you eventually scrub off all the leaf stains, finish by hosing down the deck with clean water. If not, move on to the next cleaning method.
2 .Soak Stains with Ammonia
If scrubbing with soapy water doesn’t remove the leaf stains, mix up a slightly stronger cleaning solution: Pour one gallon of water to a bucket, then add one cup of ammonia. Mix well, pour the diluted ammonia onto the deck and wait 15 minutes. Again, as with soap and water, keep the surface wet for the full 15 minutes. Then, scrub away the stains with a stiff-bristle nylon brush. Repeat, if necessary, to remove the last bit of staining, then rinse the deck with plain water.
3. Bleach Out Stubborn Stains
Stubborn leaf stains can often be removed with bleach. But I recommend using powdered oxygen bleach, not liquid chlorine bleach, and here’s why: Oxygen bleach doesn’t evaporate nearly as quickly as chlorine bleach, so it stays on the surface longer and is more effective at lightening leaf stains and killing mold and mildew. Plus, oxygen bleach is less harsh, so it won’t bleach the color out of your clothing or harm surrounding vegetation.
Begin by mixing one cup of oxygen bleach into one gallon of warm water. It’s important to use warm water to dissolve the oxygen-bleach powder. Mix well and pour the solution onto the stains. Wait 15 minutes, and then scrub the surface clean with a stiff-bristle nylon brush. If the leaf stains are lightened, but still visible, repeat with a second scrubbing or mix a stronger solution: Add two cups of oxygen bleach to one gallon of water, then soak and scrub away the stains. When done, hose down the deck.
4. Step Up to TSP
If you’ve not been able to remove leaf stains from your deck with any of the first three cleaning methods, then it’s time to try something a bit stronger: Tri-sodium phosphate, commonly sold as TSP, is a powerful—but safe to use—all-purpose cleaner that’s readily available at hardware stores and home centers. It’s sold in both powder and liquid form, but the powder is much more affordable and just as effective.
Start by pouring three quarts of warm water into a bucket, then add one cup of TSP and mix well. Now, to boost the cleaning power of the TSP, add one cup of oxygen bleach to the bucket. Mix again, then pour the cleaning solution onto the stains. Wait 20 minutes or so, then scrub with a stiff-bristle brush. Rinse the surface with plenty of clean water and check the stains. Repeat, if necessary.
5. Last Resort: Commercial Cleaner
When all other cleaning methods fails, try removing leaf stains with a deck-and-fence cleaner. Mix and apply the cleaner, as recommended by the manufacturer, then scrub the surface clean. To speed up the process, you can use a pressure washer to apply the cleaner and blast off the leaf stains, but be very careful not to damage or etch the wood decking. Use the widest fan-spray tip, stay at least 10 inches away from the surface, and aim the stream at an angle, not straight down.
Once you’ve cleaned all the leaf stains off your deck, remember when next autumn rolls around, get out there and sweep or blow off the leaves as soon as they begin to fall. That’s the surest way to prevent leaf stains.