How To Clean & Remove Green Algae From A Fence

Remove algae and mildew and clean your wooden fences with ease with our step-by-step guide.
Written By: Richard Morgan | Updated:
How To Get Green Off Fence
Richard Morgan/DIY Works

Wooden fences are a great way to add a natural finish to your garden, and when clean, they look great. However, keeping a fence clean is often neglected, and it can eventually turn green over time, which is caused by dirt, algae and mildew.

Whether you wish to use a pressure washer or bleach to clean your fence, both are very effective. We prefer pressure washing the fence due to how easy it is, but if you don’t own one, scrubbing bleach into the wooden fence panels is the best alternative. To give you an idea of how to clean and remove green algae from a fence successfully, below is a walkthrough of both methods.

How To Clean A Fence

Using a pressure washer to clean your fence and remove green algae is by far the easiest and most effective method. However, you must avoid using a high-powered setting on your machine. This is because the high pressure may cause damage to the wood. Ideally, you want to use a medium power setting and a wide spray pattern.

Depending upon how thoroughly you wish to clean your fence, you may want to use a dedicated wood/fence detergent. These come as spray-on formulas or even bottles that you can plug into your pressure washer. Although this is optional, we have included it as a step, but even without a detergent, you can achieve great results.

With the pressure washer setup, you can proceed to clean the fence using the following steps.

  • Rinse off loose debris from a distance or low-power setting
  • Manually/plug in a detergent into your machine and spray it onto the fence
  • Allow the detergent to get to work and rinse it clear
  • Stand 2 to 3 feet away and set your machine on a medium power setting and wide spray pattern
  • Spray the fence using long and even strokes
  • Avoid spraying one particular spot for too long

As you can see from the photo we took whilst we were cleaning the fence, the results whilst it was still wet were very clear to see.

How To Clean Fence

Richard Morgan/DIY Works

Below is a video that we posted on our YouTube channel that shows the pressure washing of the fence in action.

Before & After Results

how to get rid of green algae on fences

Richard Morgan/DIY Works

The above photo shows how our wooden fence was covered in green algae, and this was primarily caused by an overgrown bush that we removed. However, after using the pressure washing technique discussed above, the green algae was removed, and the fence now looks much better. Although there are areas that could do with additional cleaning, this was the result of pressure washing for only 10 to 15 minutes.

clean green algae from wooden fence

Richard Morgan/DIY Works

Cleaning Without A Pressure Washer

Not everyone owns a pressure washer, and many people may not want to use it to clean their fence due to the worry of damaging the wooden fence panels. However, it’s still possible to effectively clean a wooden fence without pressure washing. This can be achieved using bleach and water or a dedicated fence cleaner.

To clean the fence using this method, dip a bristled brush into the solution (bleach or a dedicated cleaner) and then proceed to scrub the fence. Once you have scrubbed the dirt, allow the solution to sit for up to 10 minutes before rinsing it clean using a garden hose. If you notice that there is still green algae or dirt on the fence, repeat the process.


Whether you clean your fence with or without a pressure washer, cleaning it in the first place can make a huge difference. Over time, the fence can become very weathered and green algae can form, which can ruin its appearance.

Although you can paint the fence, many people (including myself) prefer the natural appearance of a wooden fence and cleaning it from time to time is highly recommended. If you require any advice regarding cleaning your fence, feel free to get in touch with our team.

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