5 Best Patio Cleaners to Remove Dirt, Mould, Algae & Moss! (2021 Review)

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The best patio cleaners should see results in just a few days, yet provide at least six months of protection. They should be easy to apply with either a sprayer or watering can, and ideally, not need rising after application.

Moss, algae and mould are common problems on my patio, especially in the damp, colder months. I’ve significantly researched and tested the best patio cleaners, and this is what I recommend…

What is the Best Patio Cleaner?

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Comparing The Best Patio Cleaners

Use the dropdown to sort the table by the feature that's most important to you.

  • Best For
  • Max. Treatment Area
  • Size
  • Time to Visible Results
  • Duration of Results
  • Rinsing Required
  • Cost
  • Our score

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In-Depth Reviews of Our Recommended Patio Cleaners

Pro-Kleen Patio CleanerPro-Kleen Patio Cleaner

Best patio cleaner overall

Speed of Results

Pro-Kleen Patio Cleaner Review


  • Max. Treatment Area: 200 sqm
  • Size: 5 L
  • Time to Visible Results: 2 Days
  • Duration of Results: 6 months
  • Rinsing Required: No

If you look at your patio, paths or decking and curse the algae or mould that seems to always grow back, you might be seeking a long-lasting solution.

The Pro-Kleen Patio Cleaner is a successful remover of mould and algae from patios, paths and decking, with its effects lasting for up to six months.

This cleaner gets to work immediately and within a couple of days your patio will be free of mould and algae – looking its best all summer long! So if you’ve got several garden gatherings lined up, you’ll only have to do one big clean.

It’s good to know that results will appear in a couple of days. So, if you’re cleaning ahead of a party, make sure you use this product a few days before to ensure your patio is looking fresh on the big day.

This product can also be used on fencing, sheds, caravans, conservatories and uPVC windows, so you don’t have to buy separate products for these jobs! It’s a very powerful option, easily removing all sorts of grub and grime.

The concentrated formula is highly effective but safe to use. Although it doesn’t contain bleach or acids, keep kids and pets away until the area is dry.

Take extra care handling this solution, to avoid harm to your eyes and skin.

To use this patio cleaner, dilute 1-part cleaner to 4-parts water, then apply with a garden sprayer or watering can. There’s no need for scrubbing or rinsing (which is always excellent news!).

It’s ideal to use this product when there’s no rain forecast for a couple of days – just to ensure it has time to fully work. This could prove difficult if you’re wanting to clean your patio in winter.

It comes in a 5L bottle which is enough to make 25L of diluted solution. This is a fairly large volume of product, compared to others on the market, making this option quite cost-effective.


  • Does a great of job cleaning your patio and killing moss with minimal effort
  • Can be used on all outdoor hard surfaces including garden furniture
  • Visible results in just a few days
  • Very easy to use with a hand spray pump
  • Provides 25L of diluted solution, which should last you several applications


  • A lot of care is needed when using this cleaner to avoid it making contact with your skin or eyes
  • Need to use during a dry few days - difficult to predict in the UK!
  • Although it contains no bleach and no acid, it is still not safe for children or pets
  • A sprayer will need to be purchased separately
  • Will need to be applied a couple of days before a garden party, if you're cleaning ahead of an event

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Wet & Forget Moss Mould Lichen & Algae RemoverWet & Forget Moss Mould Lichen & Algae Remover

Best for long results

Speed of Results

Wet & Forget Moss Mould Lichen & Algae Remover Review


  • Max. Treatment Area: 300 sqm
  • Size: 5 L
  • Time to Visible Results: 3 Days
  • Duration of Results: 12 months
  • Rinsing Required: No

If you’ve ever scrubbed your algae-fied patio, only for it to grow back in a couple of months, you’ll know true frustration. However, I’ve found an effective product that can prevent this from happening so quickly.

The Wet & Forget Moss Mould Lichen & Algae Remover continues to work in the weeks after you first apply it, preventing the quick regrowth of mould and algae.

Interestingly, the ingredients are actually reactivated each time it rains. And there are plenty of opportunities for that in the UK! The length of time that this product prevents regrowth for is excellent for the market: at least 6 months.

So, if you’ve tried other patio cleaners before, you should find that this product (and its active ingredients) promotes a cleaner patio for longer.

This patio cleaner is safe and effective for use on a wide range of materials, from teak to marble.

It’s non-acidic, contains no bleach and is biodegradable. As is typical for these kinds of products, you must keep children and pets away from the treated area until it’s dry.

One bottle will treat up to 300 m², although this does depend on how porous the material being cleaned is. For example, materials like concrete and granite aren’t very porous, so these won’t waste any product by soaking it up.

However, if your paving is made of permeable clay pavers or dry-laid pavers, you’ll find that more product is lost through the patio itself or through the gaps between the paving stones.

The product is very simple to use, simply dilute and apply with a spray or watering can and let it get to work. You can then head off to have a nice cup of tea because your work here is done!

Although a downpour of rain will reactivate this solution, it’s still important to apply it on a dry day.

It will remove moss, mould and mildew and also gently remove any unsightly stains from all outdoor surfaces. Despite its effectiveness, results take a couple of weeks to appear which is longer than other products.

It’s easily one of the best patio cleaner products available because it’s so effortless to use and effective, plus will cover a really large area.


  • Delivers the results of a pressure washer without damaging your patio or paving
  • Contains no harsh chemicals
  • The active ingredients prevent recontamination, meaning a cleaner patio for longer
  • No scrubbing is required


  • Results are slower than others on the market - generally visible within a few weeks
  • Although it contains no harsh chemicals, this product can still cause eye and skin irritation
  • Needs to be applied on sunny days, when the patio surface is very dry
  • Kids and pets need to be kept off the treated area until the surface has fully dried

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Patio Magic! Mould & Algae KillerPatio Magic! Mould & Algae Killer

Best for moss and algae

Speed of Results

Patio Magic! Mould & Algae Killer Review


  • Max. Treatment Area: 85 sqm
  • Size: 2.5 L
  • Time to Visible Results: 4 Days
  • Duration of Results: 6-9 months
  • Rinsing Required: No

In the past, patios would have to be cleaned every time new mould or algae grew back. But now, new products have been developed with reactivation technology – chemicals that can continue to kill regrowth, weeks after you’ve applied the product.

The Patio Magic Mould & Algae Killer is one such product! It continues to remove the regrowth of mould and algae, even if you applied the solution months ago.

Patio Magic kills green mould in 2-4 days and continues to clean the treated surface in the following months. As a result, the effects of the product last between six and twelve months after the initial application.

So, although one bottle will cover up to 85 m², which is less than other products on this list, it’s likely to last a long time as you won’t need to re-apply it very frequently.

Another of this product’s features is that it doesn’t specify sunny conditions to be essential for application. Though results might not be as effective, you can clean your patio with this product in the winter if you want to.

It’s suitable for use on a variety of outdoor surfaces: patios, decking, driveways and fencing.

Plus, it can also be used to treat mouldy walls and fences before painting them, removing mould that would otherwise ruin the finish of the paint. So, if you’re planning a big garden spruce up, this multipurpose patio cleaner could be super helpful.

It’s worth knowing that this product will not work as effectively on black spot. This is fine if you’re wanting to remove other kinds of mould from your garden, but if you’re particularly plagued by black spot, this might not be the best patio cleaner for you.

With no rinsing required, this cleaner is very easy to use, simply spray it with a low-pressure sprayer, or use a watering can with a fine rose, then leave it to get to work.

This product can be purchased alongside a battery powered sprayer, although this is not essential for an easy application method. A sprayer, however, might make product distribution more economical.

It’s safe to use and children and pets can enter the treated area once the product is dry.


  • Suitable for both indoor and outdoor use so it’s more versatile than others on the market
  • Most users saw visible results within a week
  • Once dry there is no strong smell
  • Can be applied using a watering can instead of a sprayer
  • Continues to kill regrowth after first application


  • Some users saw very little difference to the moss between patio slabs
  • Although it can be applied in most conditions, results tend to be quickest when applied in bright sunshine
  • A lot of product is needed for maximum benefit which makes this more expensive than others on the market
  • Results aren’t quite so impressive on black spots
  • Children and pets must be kept away from treated area

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Smartseal Patio Clean XtremeSmartseal Patio Clean Xtreme

Best for speed of results

Speed of Results

Smartseal Patio Clean Xtreme Review


  • Max. Treatment Area: 40 sqm
  • Size: 5 L
  • Time to Visible Results: 1 Day
  • Duration of Results: Not listed
  • Rinsing Required: Yes

Whilst some patio cleaners cannot tackle black spot, this one can.

The Smartseal Patio Clean Xtreme is a powerful patio cleaner, designed for removing stubborn black spot from block paving, concrete and natural stone.

This highly effective cleaner contains 4 powerful active ingredients, including biocide to inhibit future growth of mould and black spot. It will clean your patio quickly and thoroughly, diminishing the need for a full pressure wash.

When treating black spot this product should be used neat, and for all other moulds diluted at a ratio of 1:1. It can be left on the surface for up to 60 minutes before needing to be rinsed off.

Lots of patio cleaners do not require rinsing, so this could be considered an inconvenience. However, if you’re really struggling with black spot, this could be worth it to you, as not many patio cleaners can defeat this strain of mould.

Additionally, this cleaner must be applied to a wet surface to work fully. These steps of wetting and rinsing make this product a lot more work than others on the market.

It’s the best patio cleaner I found for tackling black spot and will really help get a clean finish out of a difficult-to-treat patio. I could tell it was a heavy-duty product because I saw results in only an hour.

Equally, you must be very careful with this product as it’s a lot stronger than other patio cleaners and can cause harm to your eyes, skin, children, pets and garden wildlife.


  • One of the best on the market for removing black spot
  • Both eliminates fungus and algae, and prevents regrowth
  • Results visible in just an hour
  • Replaces the arduous and loud task of a pressure wash


  • Needs to be applied to a wet area and rinsed off, so a lot more work than those which can be applied dry
  • Some users have noticed discoloration to certain areas of their patio
  • Hand, skin and face protection is needed
  • Contains a lot of chemicals which can be harmful to pets, plants and wildlife

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Algon Organic Path and Patio CleanerAlgon Organic Path and Patio Cleaner

Best organic patio cleaner

Speed of Results

Algon Organic Path and Patio Cleaner Review


  • Max. Treatment Area: 480 sqm
  • Size: 20 L
  • Time to Visible Results: 2 Days
  • Duration of Results: 9 -12 months
  • Rinsing Required: No

Sometimes it feels like you need lots of different products to get your garden looking fresh. And so, I find it to be really helpful when there’s a multipurpose product that reduces my total spend.

The Algon Organic Path and Patio Cleaner is one such product. It will remove dirt, mould and lichen, as well as kill weeds and moss. Most other patio cleaners only promise to remove mould and algae.

So, if you’re wanting to have a big clean of your garden, de-weeding and all, this product should reduce the total cost and effort of your tasks as you’ll only need one product.

This Algon cleaner is safe to use on wood and hard surfaces, which gives you lots of options for what you can clean.

The environmentally friendly ingredients are biodegradable, containing no bleach or acids. They are therefore safe to use by homeowners with pets and children, although they should be kept away from the application process until the area dries.

To use this product simply dilute it at 1-part Algon to 3-parts water then apply with a sprayer, soft broom or watering can. With no need to rinse, application time can be kept short and sweet.

One thing to bear in mind is that if this product is used on a windy day, it could kill plants nearby. You obviously only want to kill weeds, not your lovely flowerbeds!

Users have also reported needing to use a wrench to open the lid, as it’s so heavy-duty. This might be an important consideration if you have mobility issues in your hands.

Algon also makes a ready-to-use version of this product which has a sprayer. It’s not as cost effective but it is useful if you just have a small area to spray and don’t want to invest in a pressure sprayer.

A few days after application, mould and lichen will begin to disappear, stains will be removed, and your patio or decking should look brand new. As results aren’t instant, you might want to clean your patio well in advance of any upcoming outdoor event you might be hosting.

Much like the other best patio cleaner products, this patio cleaner also goes on working, reactivating each time it rains, for up to a year.


  • Safe for pets, wildlife and children once the product has dried
  • Works even on very heavy moss infestations and weeds
  • Results visible within a week
  • No need to rinse later, can simply be applied then left to work
  • Continues to kill regrowth for up to a year


  • Produces a strong seaweed smell
  • A sprayer is recommended for best results
  • Cannot be applied on a windy day as it can kill plants
  • Awkward to decant without a funnel due to huge 20L size
  • Pets and children must be cordoned off during application process

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Things to Know Before Buying Patio Cleaner

Despite living in the unpredictable UK climate, we still spend a lot of time in the garden – even when the weather isn’t great!

Of course, one thing that can put us off fully enjoying our patio is an ugly layer of mould. Mould, grime, algae can all make an appearance, and they can be quite slippery and dangerous too!

You might be hosting a summer party and wanting your garden to be on top form for the event. Or, your elderly in-laws might be visiting, and you’ll want the slippery patio to be made safe.

Luckily, giving your patio a spruce up with a specially-designed patio cleaning solution is a fast and effective way to get your garden looking great before the sun comes out.

There’s a huge range of patio cleaners on the market, which can make it tricky to find the best one. Some are more suited to cleaning different types of mould and algae, and some require different application methods. Some promise longer lasting results, and products can vary in volume and value.

These are all factors and features that could be important to you. If you’re looking to purchase patio cleaner, but aren’t sure what to go for, the following tips will help you make an informed choice:

Patio Cleaner Vs. Pressure Washer

While a pressure washer is a good option when it comes to cleaning your patio, they are far more expensive than patio cleaners and certainly require you to put more work in. Jet washers can also damage your patio if used too often.

Areas that are grouted can be dislodged by vigorous scrubbing or jet washing, so for grouted patios it’s especially recommendable to use a patio cleaner over other cleaning methods.

Patio cleaners don’t require fierce scrubbing or hard work. In fact, they often require next to no work from you at all. With most patio cleaners you simply have to mix the solution and spread/spray it over the patio – that’s it! The best patio cleaners don’t even require you to rinse the area. Plus, these products won’t damage the surface or affect the colour of your patio.

While jet washers are great for deep cleans every so often, a patio cleaner is really all that’s needed for a quick spruce up which will really have lasting results.

Look for a Safe Patio Cleaner

Patio cleaners can contain a range of chemicals, both safe and unsafe for humans.

When looking to buy a patio cleaner, it’s advisable to look for an eco-friendly patio cleaner that won’t harm children, pets or wildlife. There are plenty out there, and it’s a good way to give you peace of mind when using it – there’s no need to use chemicals that are harsher than necessary to get the job done!

As a general rule, it’s a good idea to let your patio dry before you allow your kids or pets back outside.

Ease of Use and Versatility

Patio cleaning solution is generally very easy to use. Different brands require different levels of dilution, but it’s not difficult to measure out the formula into a separate container.

Patio cleaners can also be very versatile, with some solutions not only able to clean patios but other hard surfaces which also attract algae and mould, such as caravans and window frames. The Pro-Kleen Patio Cleaner, for example, can be used to clean roofs, fending, uPVC windows and motor homes! Having a versatile product can make it even better value for money, as well as make your life easier by not requiring you to buy separate cleaning products.

Lastly, there are products which don’t need rinsing. These can really save time and are so simple to use. After applying the solution, you simply wait for it to dry, and that’s it! No need to return to wash it off. This can be a great help if you’ve got other jobs to get on with.

Cleaners with Long-Lasting Results

Patio cleaners can vary in terms of how long they keep delivering results for.

Most products are long lasting, with some able to keep mould and algae at bay for up to 12 months after the initial application.

As seen in the product reviews on this page, some patio cleaners ‘reactivate’ when it rains. These tend to be the products with the longest-lasting effects because there’s no need to re-apply manually, they’ll just get back to work when there’s precipitation.

You’ll also find that there are some cleaners which are better suited to giving longer-lasting results when treating different types of mould. If you’re having a particular problem with black spot mould, for example, the Smartseal Patio Clean Xtreme states it can be used neat to specifically target this type of issue, keeping it effectively at bay.

Size of the Bottle and Dilution

As mentioned, patio cleaners generally require dilution. It’s good practise to check the dilution of the patio cleaner you’re looking at – some smaller bottles may be better value for money than larger bottles if they are more concentrated.

If you have a very large patio, look for a patio cleaner that covers a wider area. Most bottles of patio cleaner will list the coverage area in square metres, so you can check how many cleans each bottle will give you.

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Patio Cleaner FAQs

How can I properly clean my patio?

Routine brushing will keep it free from leaves and debris but removing stubborn dirt will require the use of a patio cleaner. You can use a pressure washer or patio cleaning product. Be careful as pressure washers may damage grouting.

Using a pressure washer: Make sure your patio is swept clear, and always start with a low setting. Increase the pressure gradually. Remember that whilst very high pressure might be the most effective, it can damage the surface of your patio. Work from a shallow angle and from a good distance to prevent putting exerting too much pressure on your patio slabs.

Using chemical cleaner: Ensure your patio is swept clear. Remove any plants or furniture. Create your cleaning mix (most solutions will need diluting). Use a watering can to distribute the cleaner evenly all over your patio. Leave to soak according to the manufacturer’s instructions. Rinse if necessary.

How do I use patio cleaner?

  1. Apply your patio cleaner on a day when rain is not expected.
  2. Check the directions on your patio cleaner to see if it needs diluting and what ratio of water to add.
  3. Keep children and pets from the area until the product is dry.
  4. Apply your patio cleaner with a low-pressure spray if possible. Alternatively, you can use a bucket and broom, or watering can.
  5. Leave the product to get to work. Bear in mind that the active ingredients in patio cleaners can take a few days to work. On very badly affected patios it may even take a few weeks before all the stains are completely removed.

Use a patio cleaner regularly on hard surfaces to remove mould and algae as these can make your paths and patios slippery and unsafe.

How do I remove black stains from patio slabs?

Black spots that grow on your patio are spores from black lichen. They are carried by the wind onto your patio, and they can be frustratingly difficult to get rid of!

Use a patio cleaner that specifically targets this type of mould. You may have to use the product neat. It will also inhibit the mould from returning.

Be prepared that patio cleaners designed to remove black spot are often very chemically strong and must be handled with caution.

How often should I clean my patio?

If you are pressure washing your patio, only do so once a year. However, you should still regularly sweep your patio to keep it looking good.

If you are using a simple patio cleaning solution, you can use it up to 4 times a year, or whenever you feel your patio needs a spruce up!

What is causing algae and mould to grow on my patio?

Green algae and mould grow in shady and wet areas. They thrive on shaded patios as these areas often have minimal drainage and hardly any sunlight. Sunshine will evaporate water, preventing the growth of algae better than in shaded areas.

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