UK’s Best Patio Cleaners for Removing Moss, Lichens & Algae

Written by Dean Wilson

Is your patio or driveway in need of a deep clean? You’re not the only one! Sadly, over time garden patios attract a combination of moss, mould, algae, lichens and dirt that leave the surface slippy and discoloured.

Thankfully it doesn’t take much effort to bring it all up, provided you have the right products to hand. A decent detergent will keep your patio surface looking like new for up to a year – many utilise a preventative formula that will stop future growth for a long time.

Note that some cleaners do work best with a pressure washer if you have one to hand. If not don’t worry – a stiff bristle brush should do the trick, you might just need to put a bit more effort in for any stubborn areas.

Our #1 Top Pick
Pro-Kleen Patio Cleaner Simply Spray and Walk Away Green Mould and Algae Moss Killer for Patios,...
5 Litres
170² Metres
Also Consider...
Wet & Forget - Moss Mould Lichen & Algae Remover (5 Litre)
5 Litres
100-300² Metres

Last update on 2021-01-07 / Affiliate links / Images / Pricing from Amazon Product Advertising API

After mixing with water, you should apply all of the detergents in our list with a watering can or low-pressure pump sprayer.

What Types of Patio Cleaner Are There?

To be honest – a lot of them use similar biocide formulas, despite how much they may claim to be different. However, it is true that some formulas achieve better results than others, with varying costs. Hence why we wanted to put together this guide.

In this review we look at various detergents and compare the effectiveness, cost and environmental impact of each. We’ve clearly stated our top pick and value item below for ease of purchase.

Feel free to get in touch or comment below should have any questions about any of these products. Let’s begin…

Best Pick: Pro Kleen – Spray & Walk Away

A simple and easy product that shouldn’t require a pressure washer

Cost: £16.95

“Simply Spray – And Walk Away” is the mantra that Pro Kleen live by – a statement which couldn’t be any more accurate.

You’re actually unlikely to need a pressure washer for use with Pro Kleen. Simply mix 1 part with 4 parts water, and spray on any surface in your garden that has been discoloured by algae – patios, outdoor furniture, driveways, even roofing – this product will work on them all. After a few hours you’ll notice the surface has started to really brighten, with any mould completely fading away over the next few days.

One feature we absolutely LOVE about this product is its [minimal] environmental impact. The product is non-acidic with a pH8 rating. To put that in perspective, water is rated pH7. That’s incredible. There’s no harmful bleach and the product is biodegradable, so it won’t harm any garden wildlife you might currently enjoy.

If necessary, we’d recommend using a stiff brush or pressure washer to deal with any dead moss or mould that has been left behind. Do this after the product has been left to sit for a few days and it should come up a treat. Most of the time you’ll be able to skip this step though.

On its own as a 5L buy, the product is pretty expensive, so we’d recommend bulk buying if you want to get the best discount. You’ll probably use more than you think, and an unlimited shelf life means it can be saved for use on future occasions.


  • Fantastic results on patios and other garden objects that are heavily covered in organic growth such as moss and algae.
  • Environmentally friendly with a non-acidic, fairly neutral pH balance.
  • The product has unlimited shelf life – so if you don’t use it all first-time round, it will save again for future use.


  • Not so great if dirt is your main issue – you’ll need to use in conjunction with a pressure-washer to get the best results.
  • You’ll need to buy the product in bulk to get a good deal on the price.
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Value Pick: Patio Magic! Cleaner

A low-cost option suited to prevention rather than the cure

Cost: £9.00

Patio Magic is another popular detergent that will help to control moss & algae. Whilst comparatively per litre it probably costs a similar amount to our top pick above, unlike Pro Kleen it is available in smaller 2.5L containers which are obviously cheaper. But you need to bear in mind that 2.5L may not be enough for the surfaces you need to clean.

The product is a concentrate, so you’ll need to mix it with water (1 part / 4 parts water). Patio Magic claim that their 2.5L bottle will cover up to 85M² but we feel this is a little over-ambitious. If you’re wanting to spray the product at a high enough concentrate to be effective, we feel you’ll probably be able to cover half that.

In truth this product is probably most effective at preventing re-growth, rather than treating a surface that has already been covered in dirt and algae. For this reason we’d probably recommend pressure-washing or treating your surface in another way to clean it, before using Patio Magic to prevent future growth.

Note that this product is best used on a warm, sunny day, as it makes the formula more effective. You’ll notice better results than if you use it on a cold, cloudy day.


  • A value option if you’re looking to keep costs low.
  • Contains biocides which are great at preventing the future growth of moss & algae.
  • Product is broken down naturally in garden soil.


  • Probably only really suitable for surfaces that have already been cleaned – or for use with a stiff brush or pressure washer.
  • Can cause skin irritation and eye damage – the right precautions should be taken during use.
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Wet & Forget

Probably the most effective product we reviewed – but comes at a premium price

Cost: £31.47

This product makes some bold claims which surprisingly, appear to ring true. Amongst them is the claim that this product is used by a number of famous worldwide landmarks including the Sydney Opera House and some of the Disneyland theme parks in Florida. Whilst we’re unable to verify this, we can see why these institutions would use this product.

Firstly, it’s incredibly effective. The product has a unique advantage once applied, in that every time it rains the product is re-activated. This makes it a fine choice if you’re looking for long-term protection against mould and lichens.

It’s more concentrated than other similar products in this category, so a 5L bottle should last for a good amount of time. It should be mixed 1 part / 5 parts water and still be strong enough to be effective.

Unlike other options in this list, Wet & Forget does not need to be used with a pressure washer or cleaning brush. In fact, they actively recommend not using a pressure washer to prevent spreading the problem.

As well as being suitable for usual surfaces like driveways and patios, this product is also recommended for other applications ranging from awnings, aluminium cladding, decking – all the way through to outdoor objects like fibreglass boats, tarmac, tennis courts and pretty much any outdoor object you can think of! It really is incredibly adaptable.

Were it not for the high cost, this product would undoubtedly be our best pick. We strongly recommend this detergent provided cost is no boundary.


  • Product will continue to activate over time – increasing the time between treatments.
  • It’s incredibly malleable and can be used on almost any outdoor surface to maximum effect.
  • The 30-year-old formula definitely works, unlike some other low-cost products which can be hit-or-miss depending on the surface.


  • You will need patience as the lightening process happens over time (usually a few weeks) and relies on rainwater to continue seeing improvements.
  • This is one of the highest cost products in the patio cleaner range.
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Jarder Spray & Leave

A good product, but doesn’t do enough different from our other picks

Cost: No products found.

Jarder is another ‘spray and forget’ detergent that is intended for use on all hard outdoor surfaces.

It is very highly concentrated (1 part mixes with 6 parts water) so despite the high price-point, you are getting a lot for your money. Jarder claim to cover up to 240M squared with a single 5L bottle, which would be astonishing if true.

It shows similarities with our topic pick and the two likely share a similar formula, though this product will set you back a little more money.

As with all of these products, you need to leave the product for a few weeks before you really start to notice the difference. You can apply Jarder neat if you have a really big job on your hands, but generally the ideal composition is somewhere around 1:5 with water.


  • No shelf-life limit so can be saved for a number of applications around the home.
  • Dilution ratio with water is flexible depending on the size of the job.
  • It is effective and will prevent re-growth over time. The formula should last for 6-12 months.


  • Nothing really differentiates this product from other popular picks, aside from it being more expensive.
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Smartseal Patio Clean Xtreme

Best if you’re looking for a product to clean black stains from stone

Cost: No products found.

Our final item in this list is a little different from our other picks, as it specialises in the removal of black-spot lichens that can often build-up on stone walls and patios. The product can be used on various garden masonry surfaces including concrete, limestone, Indian sandstone & block paving.

We wanted to include this product as we know that black spots are a common occurrence on exterior stone that hasn’t been cleaned in a while. This product uses 4 fast-acting ingredients to effectively deal with the organisms that cause the discolouration.

Smartseal is not highly concentrated and you only need to mix 1 part with 1 part water, so bear this in mind when considering the quantity you think you’ll need.

In summary this is a product that is highly suited for very specific needs. For its intended use, we’d definitely recommend it.


  • The product is extremely fast-acting – usually achieving the desired results within an hour!
  • Speciality product that is tailored specifically for black stains on stone – a common issue that is usually difficult to resolve.
  • Usually requires no scrubbing or pressure washing.


  • Product should not be used on tarmac or asphalt.
  • Concentration is low – you’ll need a lot if you have a significant surface area to cover.
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How to Properly Clean A Patio or Driveway

Most of the products chosen in our list are ‘spray and forget’ detergents, when you needn’t do much other than apply with a sprayer or watering can, then come back to check out the results.

However, it’s not always so simple and depending on the end-result, you may need to carry out further work to achieve the best results.

If your patio cleaning fluid hasn’t been entirely effective, we recommend following these steps:

  • Either re-apply the cleaner or (if you’ve run out) use water to re-activate the product you’ve already applied.
  • Scrub with a wire brush (this may need to be handheld depending on the surface) and ensure that you’re really working the bristles of the broom into the surface.
  • If (after a few days) you are still seeing no improvement, you will probably need to resort to the power of a pressure washer. Sometimes surfaces that haven’t been cleaned in a while can become battle-hardened and they may need something with a little extra clout. You can find pressure-washers in most good DIY stores, or even hire a premium washer for a few days at less cost.
  • Stone surfaces can be sprayed at near maximum pressure, but you should be careful not to set these too high for wooden surfaces such as decking. Usually we recommend working upwards from the lowest setting until you see the desired impact.

And that’s it! We love to see before-and-after shots so feel free to get in touch or post yours below.

About the author

Dean Wilson

I'm an avid gardener and home DIY enthusiast from Yorkshire in the North of England. I'm passionate about helping our readers get out into their gardens - by making the most of the outdoors and ensuring they get the best possible deals on their gardening equipment. I also believe strongly in the preservation of our beautiful garden wildlife.

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