Garden & Lawn

5 Best Decking Cleaners For Removing Algae, Moss & Dirt

Last updated on January 5th, 2022

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We look at some of the the best cleaners for wooden decking. Unlike decking oil and paint, a decking cleaner is used before treating with oil or paint or as a general cleaner between yearly decking treatments

Decking cleaners are crucial when trying to keep your decking in shape. These cleaners help strip away layers of dirt and keep mould and algae from invading your deck, the best part is that in most cases, all you need to do is apply and walk away and within a few days you will see good results. They can be used together with a pressure washer for removing the dirt and moss first before applying the cleaner. Decking cleaners are used to prepare the deck for other processes, for example, staining and repairs. Finding the best decking cleaner means finding the one that works the best for your specific kind of deck. But as you will learn, any of our picks will do the job but we do have a personal favourite.

There are a number of decking cleaners on the market that you can purchase. Below are examples of some notable decking cleaners that have proven effective. You can read through our buyer’s guide to understand which factors to consider before purchasing a decking cleaner.  By the end of this guide, you can confidently select the best deck cleaning solution like a professional.

In a hurry? The ULTIMA-PLUS XP Mould & Algae Killer Remover is probably a good choice for most people and it can also be used on a range of other surfaces too. An economical option compared to the rest, this 5-litre concentrate produces 50-95 litres of cleaning solution that covers a vast 400m2 area.

Best Pick

ULTIMA-PLUS XP Algae & Mould Remover

  • Provides protection from moss & algae for up to several months by forming a protective barrier once dry.
  • The product is biodegradable and 100% safe as it contains no bleach or caustic substances, this means once dry it save for children and pets.
  • Has high concentrations of moss/algae/mould killer to ward of re-growth.
  • The 5-litre container can be diluted to create 50-95 litres which can cover a very impressive 400m2.
  • The solution is suitable for all hard surfaces such as driveways, sheds, fences, wooden garden furniture and even caravans.

The top 5 decking cleaners that we reviewed, including our top picks

  1. ULTIMA-PLUS XP Mould & Algae Killer – OUR BEST PICK – Super strong concentrate, apply and walk away and see results in around 3 days
  2. Ronseal Decking Cleaner – Ready to use, ideal for applying before treating decking with oil or decking protector
  3. Jarder Spray & Leave Concentrate Cleaner
  4. Pro-Kleen Moss, Algae & Mould Killer
  5. Dirtbusters Spray Today Gone Tomorrow Cleaner – Professional grade cleaner


Ronseal Ready to Use Decking Cleaner
Although you do not have to dilute the concentration, you will be able to get the best out of the solution when combined with a scrubbing brush. It deals with more than removing dirt but also removes moss, mould, mildew, fungus and algae. The 5 litre container will let you cover an area of approximately 20-24 square meters. Those looking for value for money will have noticed that it's much more expensive to treat per square meter than the concentrates, however, it does come ready to use and is perfect for anyone looking to clean their decking before applying your decking with a treatment of decking oil or protector. if you only have a small decking area to clean and no paths or fences etc, this could be the best option.

Also great

Jarder Spray & Leave Decking Cleaner
This is another very popular spray and leave cleaner, it is effective against moss/mould growth. Five litres of concentration makes 30 litres after dilution and you will be able to cover a staggering 240m2 per 5-litre container. With a strong formulation, this decking liquid will also be effective on other hard surfaces around your property so is a good multi-use cleaner. Simply apply with a sprayer or watering can and walk away. Like all the cleaners we have picked, it's also safe around children and pets once dry.

If you also have issues with moss growing on your patio, paths, driveway or any other hard surface, check out my best moss killers for this here.

Top 5 Decking Cleaner Reviews

1. ULTIMA-PLUS XP Mould and Algae Remover

MY BEST PICK – The strongest green mould & algae remover currently available

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ULTIMA-PLUS XP MY1356 Patio Cleaner & Green Mould And Algae Remover,Blue


  • Features high concentrations of moss/algae/mould killer to ward off re-growth and provide protection for several months.
  • See the results in as little as 2-3 days. Simply apply with a sprayer and walk away.
  • The 5-litre container can be diluted to create 50-95 litres. This can cover an area of 400m2.
  • The solution is suitable for all hard surfaces such as concrete paths, drives, fences, sheds and even caravans and boats if you are lucky enough to own one.
  • Safe for children and pets once the area has dried.
  • The product is biodegradable, which means its 100% safe as it contains no bleach or caustic substances.
  • Offers excellent value for money as it is sold as a concentrate.
ULTIMA-PLUS XP MY1356 Patio Cleaner & Green Mould And Algae Remover,Blue

The ULTIMA-PLUS XP Mould & Algae Killer For Hard Surfaces has been designed to clean different hard surfaces, such as large decked areas, driveways including tarmac, resin, block paving, sheds, boats and even caravans amongst other surfaces. If the surface is hard, it will clean it.

It contains a powerful moss and algae cleaner that prevents regrowth for up to a very impressive 6 months before re-application is needed. For 5 litres you can cover an area of 400m2 once the solution is diluted, but this will be nearer 200m2 when it is diluted to its strongest recommended rate. Depending on the concentration you need, you can produce between 50 to 95L from the 5 litre concentrate.

ULTIMA-PLUS XP MY1356 Patio Cleaner & Green Mould And Algae Remover,Blue

After you are done with the application, you can expect to see visible results within 2-3 days. Remember to only apply this solution when it is dry and no rain has been forecasted for 24 hours to be on the safe side. If you apply this solution in wet conditions then the application will not be effective.

This product will take care of your deck as it contains no bleach, no acid and non-caustic substances. With a PH of 8, this biodegradable decking cleaner is one of the best deck cleaning solutions on the market. You can be sure that your children and pets are safe when coming into contact with the surfaces as the product is non-toxic.

One last tip, as with most cleaners you can use either watering can or a garden sprayer, we would highly recommend using a garden sprayer as you can cover much more of an area. When applying this cleaner with a watering can it can be fairly wasteful because it simply runs off the decking, whereas with a sprayer, it sits on the decking and is usually more effective. We have recently reviewed some of the best garden sprayers (and we talk about them here) and you can pick them up much cheaper than you might think so it is well worth investing in one.

Compare the best prices from available sellers below

2. Pro-Kleen Green Mould and Algae Remover Concentrate – Simply apply and walk away

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Pro-Kleen MY16 Patio Cleaner Simply Spray and Walk Away Green Mould and Algae Killer for Patios, Fencing and Decking 5 Litre Concentrate (Makes 25 litres)


  • It is a ‘spray and walk away’ product that doesn’t need a pressure washer.
  • Offers quick results, even when dealing with severe cases of moss, mould and algae.
  • For every 5 litre container the solution can be diluted to produce 25 litres.
  • Functional in cleaning other hard surfaces like pavements and fences, roofs, artificial lawns and garden furniture.
  • Offers protection for 6 months before needing re-application.
  • The product is non-acidic, non-caustic and non-toxic making it safe for our much loved pets and children once the treated area is dry.

The Pro-Kleen Cleaner Moss, Algae & Mould Killer is supplied in a 5-litre container with a PH of 8. To give you an idea, water is usually rated at PH 7 so it is slightly more acidic than water but only just. This decking cleaner offers you a convenient way to clean your hard surfaces without using a pressure washer or needing to spend hours scrubbing away with a brush. 

Pro-Kleen MY16 Patio Cleaner Simply Spray and Walk Away Green Mould and Algae Killer for Patios, Fencing and Decking 5 Litre Concentrate (Makes 25 litres)

The idea is that you apply the concentrate and just walk away expecting results in a few days. For those without a pressure washer, this concentrate proves to be a quick fix and it offers great results on wood decking.

Appropriate for even the most severe cases of algae or moss infection, this cleaning solution can be sprayed across different surfaces including fences and outdoor furniture. You do not need to dilute this concentration much as it may not be effective. For every 5 litre container, you should get about 25 litres of decking solution that should cover a very large area. We were not sure just how large an area, but when you think that most backpack sprayers hold 20 litres max, you could spray a considerable area with backpack sprayer filled to the top.

Just like most other products that made it onto our list, it provides protection for up to 6 months and this cleaning solution is safe for pets and children once the concentration is dried. Non-acidic, non-caustic and no bleach, this biodegradable decking cleaner will leave your deck in tip-top condition and is well worth trying. At the time we looked into this cleaner, it had over 2900 reviews which further confirms how good this product is.

Compare the best prices from available sellers below

3. Ronseal Ready To Use Decking Cleaner

Ideal for use before applying a decking treatment of oil or protector

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Ronseal DC Decking Cleaner 5 Litre


  • Ready to use, no mixing with water, simply pour into a sprayer or watering can.
  • Designed to protect and revive decking wood.
  • Appropriate for use before applying deck finishes like decking oil or staining.
  • It is a powerful concentration needing no dilution to work optimally.
  • Able to cover 20-24m2 per container.
  • This product is non-toxic and will not harm the grass as well as being safe around pets and children once dry.
  • Opens up wooden pores to ensure that other floor finishes stick to the wood effectively.

The Ronseal DC Decking Cleaner 5 Litre is the product you need when looking to revive timber or if your surfaces are infected with moss and algae. It has been designed more as a pre-treatment before applying decking oil or protector that allows the oil to get into the timber more effectively.

This decking cleaner needs no dilution as you have to use it as a concentrate. This also means that there is no mixing to worry about, simply pour it into a watering can or a sprayer (ideally, a sprayer to reduce waste) and apply.

This decking cleaner works by opening up the wood and removing grime that would prevent decking finishes to be soaked up by the wood. If you are planning on staining or applying decking oil, this product will be an effective way of reviving the wood before you begin this process. Effective against stains, algae, moss, fungus, grease and mildew, this decking cleaner is able to cover an area of 20-24m2 per single container, so compared to other cleaners it does not offer as much value for money. Remember our best pick will cover up to 400m2 and make up to 95 litres of spray.

If you have a large deck you may need several of these but the fact that there is no mixing involved does make it a good alternative to the usual concentrates available. If you are cleaning your decking in preparation to apply decking oil, this is certainly worth considering.

Compare the best prices from available sellers below

4. Jarder Spray & Leave Concentrate Cleaner

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Jarder Spray & Leave 4 x 5 Litre Concentrate Cleaner - Patio Fencing Decking - Green Mould & Algae Killer (20L)


  • Features a spray and walk-away formulation, therefore, needing no pressure washer or scrubbing.
  • Every 5 litres offers a minimum of 30 litres of cleaning solution that is able to cover a 240m2 area.
  • Can be used on multiple surfaces as do all the cleaning solutions on this list.
  • Shows visible results within 2-3 days, offering surface protection for up to 6 months.
  • The solution is 100% safe for human contact once it dries up.
Jarder Spray & Leave 4 x 5 Litre Concentrate Cleaner - Patio Fencing Decking - Green Mould & Algae Killer (20L)

The Jarder Spray & Leave Concentrate Cleaner is another spray and walk decking solution on the market. All you need is to dilute the concentrate, spray the mixture, walk away and wait to see the results. For application purposes, the solution has to be diluted to make it effective without harming the surface. From every 5 litres you purchase, you should be able to make a minimum of 30 litres. These 30 litres are able to cover an area of 240m2 easily so isn’t too bad, however, we have seen cleaners with better coverage.

Apart from using it on your decking, this cleaner can be used on other surfaces too including terracotta pots, driveways, greenhouses and roofs amongst others. You will be able to make use of this solution for more than just cleaning your deck, therefore, making it a convenient purchase.

Jarder Spray & Leave 4 x 5 Litre Concentrate Cleaner - Patio Fencing Decking - Green Mould & Algae Killer (20L)

Once you have applied the solution you can expect to see visible results within 2-3 days, which you will have noticed is becoming the norm for spray and walk away cleaners. The solution will offer protection from moss, algae and of course mould for up to 6 months. If you notice some regrowth, a new application may be required and as with all cleaners, it sometimes can take a couple of treatments to really get it looking like new.

This product is not toxic to humans or pets, therefore, making it 100% safe and this is one of the factors the decking cleaners needed to have to make it onto our list. With a PH of 8, the non-caustic, non-acidic and no-bleach solution will not strip your surfaces of colour. Avoid using this product in aquatic settings as it is dangerous to aquatic life.

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5. Dirtbusters Spray Today Gone Tomorrow Professional Cleaner

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Dirtbusters Spray Today Gone Tomorrow 5 Litre Patio Decking Fence Drive Cleaner extra strength formula which removes Mould Mildew Moss Algae Lichen Killer Green Growth Remover (1)


  • The product is sprayed and left alone to work without the need of a pressure washer.
  • Has no harmful chemicals that may strip the surface or cause health damage to the user.
  • Possesses a strong chemical formulation to kill off moss/ algae/ mould.
  • The 5-litre container produces a minimum of 20 litres when diluted, allowing you to cover significantly large areas.
  • It is a commercial-grade product that is able to cover an area of 200m2 per container.
  • A great option if your are on a budget. 

The Dirtbusters Spray Today Gone Tomorrow can be fetched at an affordable price and is described as a professional-grade detergent disinfectant treatment. Featuring a strong formulation, this decking liquid is capable of getting rid of dirt, moss, algae and mould from your surfaces. Not limited to decks only, you can use this solution on your patio, shed, fences or uPVC structures to keep them in good condition.

This cleaning solution is to be sprayed and left alone to do its work. It is worth noting that it cannot be applied using a watering can. There is no need to get extra scrubbing equipment or add any other cleaning solution as it does a great job on its own.

For every 5 litres of this solution, you should be able to acquire a minimum of 20 litres after dilution. This is enough to cover an area of 200m2 with the cleaning solution, which is a fairly good coverage overall.

Avoid using this product 24 hrs before or after the rain. The surface should be dry for the cleaning solution to work optimally. Once the solution is dry, it is safe for children/pets to come into contact with the cleaned surface, which is obviously a concern for most people. As with all the products on our list, this product contains no bleach, acids or caustic substances that may harm your surfaces.

Being that it is a commercial strength product, you can expect nothing but excellent results from this, it’s not as well known as some of the other cleaners on our list but it is well worth a try and should not disappoint.

Compare the best prices from available sellers below

Decking Cleaner Buyer’s Guide

Purchasing the right decking liquid is not hard at all. When you look at your deck you want to see clean wood that has retained its appearance. Before you start any yearly treatments on your deck, such as applying a decking protector or a coat of decking protector or decking paint restorer, employ the use of the best deck cleaning solution. Depending on the level of dirt on the deck you can use a pressure washer or brush to remove dirt and thick moss from your deck. If you have layers of algae, moss or even lichen (that become very slippery and unsightly) then applying a walk away cleaner as they are often known, can have it spotless in a few days without the hassle of having to use a scrubbing brush or pressure washer.

Factors to consider

What are some of the factors to consider before you purchase a deck cleaner? Apart from how much you are willing to pay, there are a few factors such as:

Area to be covered

How large is your deck or how hard is the surface that needs cleaning? Smaller areas take up less cleaning solution compared to larger areas. Larger areas may require one or two containers of cleaning liquid. You also need to factor in the level of dirt so as to understand the intensity of cleaning required. Large areas that need intense cleaning may benefit from the use of a pressure washer instead first and maybe even 2 coats of decking cleaner afterwards.

Concentration of the cleaning solution

There are decking cleaners that need to be diluted to work effectively. As well, we have decking cleaners that do not need to be diluted, such as the Ronseal DC Decking Cleaner. Depending on the scale of dirt you may settle for either kind. It is all a matter of personal preference. One thing to remember though is that the more concentrated a cleaning solution is, the more likely it is to be effective. Ready to use cleaners can just be applied using a garden sprayer and you are ready to go straight away, whereas concentrates need measuring and mixing with water first but often offer better value for money.

Pressure washer vs spray and leave

Choosing how you will apply the cleaner for an effective cleanse matters. If you have the energy to do it, you can choose decking cleaners that need brushes or alternatively a pressure washer to clean the deck. Pressure washers are more effective if there is a serious dirt/mould build-up. Alternatively, you can pick the “spray and walk away” deck cleaners, which is probably what most people prefer just for pure ease of use. All you have to do with these is spray them and let them work their magic.


Whatever brand of decking cleaner you select, make sure that its contents are both environmentally and domestically safe. If you have children and pets running around it is even more important and it is better to get a non-toxic deck cleaner. Most decking cleaners adhere to the use of safe chemicals but it is always good to confirm.

Make sure that the product is biodegradable to save the environment from harmful chemicals. Also, check to see the PH of the cleaning solution to ascertain that the chemicals won’t strip the surfaces leaving them dry and bare. That is why most deck cleaner labels state that no bleach, acid or caustic substances are present in the solution.

Multiple uses

There are decking cleaning liquids that can be used on other surfaces such as tarmac, cobblestones, granite, wooden sheds, boats, caravans and greenhouses amongst others. If you want a versatile cleaning liquid then products like the Jarder Spray & Leave Concentrate Cleaner are the ones to look for.

If you just want a simple decking cleaner with one function, you could try the Ronseal DC Decking Cleaner.

User instructions

Most decking cleaners come with user instructions telling the user how to use the solution. Instructions including the ratio of dilution are important, as is the success rate of the solution after application. 

Select products that clearly state what to do and what not to do with the product. Some products provide additional information, for example, that their products may harm aquatic life. This is very important to consider if you are treating areas near to a water source such as a pond or stream.


Are there any safety measures to adhere to?

Yes, there are a few general safety rules that you can follow. Because you are dealing with chemicals make sure that you wear protective clothing and gear, at the very least, gloves and eye protection. Working whilst wearing protective gloves will keep the solution from splashing on your skin, which is especially important if you have sensitive skin. Also, check if the product is safe to use around ponds and keep children and pets clear of the area until it is dry.

Why bother using decking cleaner?

Decking cleaners take off moss and dirt without stripping the surface of its appearance. Manually brushing the dirty surface with basic soap and water takes time and may strip the deck of its beauty. The cleaning solution composition allows the surface to be ready for other treatments by removing elements that may prevent a successful application.

When is the best time for application?

Be sure to apply the solution when the surface is dry. It is advisable not to apply the solution hours before or after it rains. It is advisable to do the application when the sun is out but not glaring. If it is too hot, the solution will evaporate before completing the job. Ideally, you want to see a forecast of no rain for 24 hours, just to be on the safe side.

Our Final Conclusion

As you can see, picking out the best decking cleaner is not that complicated. There are many products on the market that can serve you well, even if you have composite decking. If you want long-lasting protection from moss/mould/algae regrowth, you may have to re-apply the solution every 6 months or so. Other than that, you can keep your decking in tip-top condition by applying a decking cleaner and without having to pay for professional services or put in too much effort, which is always a bonus. 

ULTIMA-PLUS XP MY1356 Patio Cleaner & Green Mould And Algae Remover,Blue
  • Ultima-Plus XP is a max-strength patio cleaner that both wipes out green mould and algae and forms a protective barrier that stops it from growing back, keeping your hard surfaces clean for months after treatment
  • You can use Ultima-Plus XP on your patio, paving, decking, tarmac, stonemasonry, bricks, wood, corrugated asbestos, greenhouse glass, and more
  • 100% safe: biodegradable. PH8. Non-caustic, no acid, no bleach and is totally safe for use around children & pets once the area has dried
  • Penetrates your outdoor surfaces creating an invisible barrier which will help to prevent re-growth for up to 6 months
  • Just one bottle makes up to 25L – covering a huge 200 square metres. This makes this patio cleaner superb value for money with it covering a large area - perfect for patios and driveways!

So have you spotted the best deck cleaning solution yet? Let us know in the comments section below and feel free to share your own experience if you have used any of the products we have mentioned to clean your decking. 

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Welcome to my site, my name is John and I have been lucky enough to work in horticultural nurseries for over 15 years in the UK. As the founder and editor as well as researcher, I have a City & Guilds Horticultural Qualifications which I proudly display on our About us page. I now work full time on this website where I review the very best gardening products and tools and write reliable gardening guides. Behind this site is an actual real person who has worked and has experience with the types of products we review as well as years of knowledge on the topics we cover from actual experience. You can reach out to me at

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