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Why Patios Go Green and Slippery in Autumn
Algae, moss and lichen thrive on damp, shaded paving, and as autumn arrives the combination of falling leaves, rain and shorter days is perfect for them. Left alone, a green film can make patios dangerously slippery, stain paving, and shorten its life. Autumn is a good time to clean, because you can treat the surface before winter and avoid slipping hazards.
You have two broad choices: scrub or pressure wash the surface, or apply a chemical cleaner that does most of the work for you. In this guide we focus on liquid treatments that you spray or water on, and we have picked six products from different price brackets.
At a Glance: Patio Cleaners Compared
| Product | Type | Size | Approx Price |
| ULTIMA-PLUS XP Green Mould and Algae Killer | Spray and leave | Standard | around £8-12 |
| Jeyes 4 in 1 Patio and Decking Cleaner | Diluted cleaner | 4L | around £10-14 |
| Jeyes Fluid Outdoor Cleaner | Classic disinfectant | 4L | around £11-15 |
| GLEAN Green Clean Patio Cleaner | Concentrate | 5L | around £13-17 |
| Patio Magic! Concentrate | Concentrate | Varies | around £16-22 |
| Wet and Forget Rapid Application | Spray and leave | 2L | around £35-42 |
Prices are approximate and change with stock.
The Products, One by One
1. ULTIMA-PLUS XP Green Mould and Algae Killer Patio Cleaner
A spray-on, walk-away style cleaner aimed at green algae and mould on patios, paths and other hard surfaces. This is among the cheaper options in the list and suits people who want a low-effort way to deal with slimy green patches without scrubbing or hiring a pressure washer.
Pros: Low price, spray-and-leave convenience, targets green algae and mould.
Cons: Results take time and rain, and heavily built-up moss may need brushing off afterwards.
Who it suits: budget-minded gardeners tackling light green patches.
- MAX-STRENGTH PATIO CLEANER & ALGAE REMOVER – Professional-strength outdoor cleaner that removes green algae, mould and lichen from patios, paving, driveways, decking and other hard surfaces, restoring your garden to a cleaner, safer finish
- HELPS PREVENT REGROWTH FOR UP TO 6 MONTHS – More than just a patio cleaner, Ultima-Plus XP penetrates surfaces to create an invisible protective barrier that helps prevent algae and mould from returning, keeping outdoor areas cleaner for longer
- SUITABLE FOR MULTIPLE OUTDOOR SURFACES – Ideal for patios, paving slabs, block paving, decking, tarmac, brickwork, stone, wood, greenhouse glass, corrugated asbestos, terracotta pots, garden ornaments and many other exterior hard surfaces
- HIGHLY CONCENTRATED FOR EXCELLENT COVERAGE – One 5L bottle makes up to 25 litres of cleaning solution, covering up to 200m², making it a cost-effective choice for large patios, driveways, paths, gardens and commercial outdoor spaces
- SAFE, BIODEGRADABLE FORMULA – pH 8, biodegradable and free from bleach, acids and caustic chemicals. Safe for use around children and pets once treated surfaces have completely dried, with no harsh odours or surface discolouration
2. Jeyes 4 in 1 Patio and Decking Cleaner (4L)
Jeyes is a household name in the UK for outdoor cleaning, and this four-litre 4 in 1 patio and decking cleaner is aimed at removing algae and moss from patios, paths and decking. A 4 litre bottle is good value for a medium-sized patio and is easy to find in shops as well as online.
Pros: Well-known UK brand, 4L is good value, suitable for both patios and decking.
Cons: Needs correct dilution and application, and run-off should be kept away from ponds and planting.
Who it suits: medium-sized patios and decking.
- 4 IN 1 COMPLETE CLEAN FOR PATIOS & DECKING - Tackle tough grime on paths, patios, decking and fencing the easy way – just use Jeyes! No mixing, no fuss—just powerful 4-in-1 cleaning action. Pressure washer compatible for an even deeper clean
- RESTORES THE NATURAL COLOUR OF HARD SURFACES - Lift away layers of sludge and slime to reveal the true beauty of your patios and decking. Jeyes driveway cleaner gets to work fast, eliminating buildup for outdoor spaces that are fresh and ready to use
- FIGHTS DIRT, LIMESCALE, STAINS & ALGAE – Get your garden summer-ready with Jeyes’ powerful 4-in-1 action. Tackling everything from stubborn limescale to ground-in dirt, this patio and decking cleaner delivers long-lasting results without scrubbing
- READY TO USE STRAIGHT FROM THE BOTTLE – The pre-diluted formula makes cleaning quick and easy. Simply apply and let Jeyes outdoor patio cleaner solution handle the tough stuff. For lighter surface growth, simply dilute for a milder application
- THE ORIGINAL OUTDOOR CLEANER – Jeyes has been keeping outdoor spaces clean and protected since 1877. Trusted by generations, with over 145 years' expertise, our products fight dirt, stains, bacteria and germs to make outdoor cleaning easier than ever
3. Jeyes Fluid Outdoor Cleaner (4L)
The classic Jeyes Fluid is a strong-smelling outdoor disinfectant and cleaner that has been used for decades on patios, paths, drains and garden surfaces. It is diluted in a watering can and applied to hard surfaces to help clear algae and moss, and the product is also used around the home for general outdoor hygiene.
Pros: Long-established, versatile outdoor cleaner, 4L lasts a long time once diluted.
Cons: Strong smell, must be kept away from ponds and watercourses, and you should follow label instructions carefully.
Who it suits: gardeners who want a classic, versatile outdoor cleaner.
- READY TO USE MULTI-PURPOSE OUTDOOR CLEANER – Need to get a greenhouse summer-ready or clean pots, patios, garden paths or pet housing - just use Jeyes! This powerful disinfectant protects your family and tackles tough grime for a hygienic outdoor clean
- KILLS 99.9% OF BACTERIA – Keep your family and pets safe with Jeyes. It disinfects and kills 99.9% of bacteria and viruses, protecting your loved ones from harmful germs
- FIGHTS DIRT & STAINS – If you’re looking for a disinfectant that does it all – decking cleaner, driveway cleaner, even outdoor drain unblocker – Jeyes Outdoor Cleaner has you covered, banishing dirt and stains so you enjoy a healthier home
- READY TO USE, NO NEED TO DILUTE – The pre-diluted formula makes cleaning quick and easy. Just apply, leave for 30 minutes, scrub with a hard bristle brush, rinse and let dry. No fuss, no mercy—just spotless results (treats up to 30m2)
- THE ORIGINAL OUTDOOR CLEANER – Jeyes has been keeping outdoor spaces clean and protected since 1877. Trusted by generations, with over 145 years' expertise, our products fight dirt, stains, bacteria and germs to make outdoor cleaning easier than ever
4. GLEAN Green Clean Patio Cleaner 5L (Concentrate)
A five-litre concentrate that is pitched as covering around 200 square metres, which makes it good value for large patios, driveways and paths. Concentrates give you more cleaning per pound, though you will need a watering can or sprayer to apply it.
Pros: Large 5L concentrate, good coverage for the price, suited to larger areas.
Cons: Needs diluting and applying evenly, and a big container needs storing safely.
Who it suits: large patios and driveways.
- 𝗟𝗼𝗻𝗴 - 𝘁𝗲𝗿𝗺 𝗲𝗳𝗳𝗲𝗰𝘁𝗶𝘃𝗲𝗻𝗲𝘀𝘀: Weather: activated algae remover that targets green algae, moss, lichen, and mould on patios, decking, tarmac, fences, concrete paths, and roof tiles. Rain: released for root - level cleaning.
- 𝗔𝗹𝗹 𝘀𝗲𝗮𝘀𝗼𝗻 𝗽𝗮𝘁𝗶𝗼 𝗰𝗹𝗲𝗮𝗻𝗲𝗿 & 𝗺𝗼𝘀𝘀 𝗸𝗶𝗹𝗹𝗲𝗿: Removes unwanted green growth, and mildew from balconies, brickwork, porcelain paving, resin drives, and paving slabs. A trusted alternative to pressure washing.
- 𝗢𝘂𝘁𝗽𝗲𝗿𝗳𝗼𝗿𝗺𝘀 𝗯𝗹𝗲𝗮𝗰𝗵 - 𝗯𝗮𝘀𝗲𝗱 𝘀𝗽𝗿𝗮𝘆𝘀: GLEAN removes green mould, moss, and lichen from natural stone walls, paving edges, and steps. No surface bleaching—just lasting results, no rinse.
- 𝗦𝗮𝗳𝗲 𝗼𝗻𝗰𝗲 𝗱𝗿𝘆 𝗳𝗼𝗿 𝗴𝗮𝗿𝗱𝗲𝗻𝘀 & 𝗽𝗲𝘁𝘀: Confidently spray around lawns, plants, and outdoor furniture. Apply using a garden sprayer, watering can, or trigger bottle - zero harsh runoff.
- 𝟱𝗟 𝗰𝗼𝗻𝗰𝗲𝗻𝘁𝗿𝗮𝘁𝗲 𝗳𝗼𝗿 𝗳𝘂𝗹𝗹 𝗼𝘂𝘁𝗱𝗼𝗼𝗿 𝗮𝗿𝗲𝗮𝘀: Dilute 1:5 to cover up to 200m². Use on paving slabs, render, composite decking, natural stone, brick paths, and driveways. Compatible with all sprayers.
5. Patio Magic! Concentrate
Patio Magic is a well-known brand in the UK patio-cleaning market, and its concentrate is designed for patios, paths and driveways, claiming to deal with algae and lichen. The brand has a strong following among gardeners who prefer a fairly gentle cleaning job and a long-lasting effect, rather than a quick blast.
Pros: Established patio cleaning brand, concentrate means a little goes a long way, suitable for patios, paths and drives.
Cons: Premium price compared with basic cleaners, and effects can take several weeks to show.
Who it suits: gardeners who prefer a dedicated patio brand.
- Use on outdoor hard surface
- No need for scrubbing and pressure washing
- Visible results in 2-4 days
- Biodegradable and children and pets need not be excluded from treated areas once dry
6. Wet and Forget Rapid Application Mould, Lichen and Algae Remover, 2L
Wet and Forget is a spray-on treatment that you apply and leave to work over weeks and months, with rain doing the work. This is a premium option at a premium price, but a little goes a long way and it is used on roofs, patios, fencing and walls as well as paving.
Pros: Spray-on and walk-away, can be used on a wide range of surfaces, long-lasting results.
Cons: The most expensive item in this list, and results are slow to appear.
Who it suits: anyone who wants a low-effort treatment for a large area, including roofs and fences.
- No Scrubbing Required: Effectively works to removes outdoor mould, mildew, and algae, with no scrubbing, jet washing or rinsing needed. Simply saturate dry surface with solution and wait for product to work its magic; apply on day with no rain forecasted
- Versatile Application: Perfect for covering large outdoor surfaces, including patios, roofs, driveways, paving, tarmac, decking and more. Whether it's your driveway or solar panels, Wet & Forget has you covered
- Powerful Reach: The attached Reach Nozzle allows you to cover up to 200m² in just 10 minutes and reach up to 8m high, making it perfect for taller buildings
- Hassle-Free: Simply attach to your hose, and the solution automatically mixes with water, just spray and walk away
- Confidence in Every Spray: While our formula is gentle, we recommend wearing protective gloves and eye protection during use
Buying Guide: Cleaning Patios Safely and Effectively
Concentrate, ready-to-use or spray-and-leave?
Concentrates are the best value and let you mix the strength you need, but need a watering can or sprayer. Ready-to-use sprays are convenient for small areas. Spray-and-leave products take longer but need almost no effort.
Check the surface
Natural stone, sandstone and some coloured paving can be sensitive to chemicals, so check the label and test a small hidden area first. Do not use harsh cleaners on painted or sealed surfaces unless the product says it is safe.
Protect plants, ponds and pets
Rinse run-off away from borders and keep it out of ponds, drains that lead to watercourses and areas pets use. Cover or water the adjacent plants beforehand, and keep children and pets off the area until it has dried.
Weather matters
Choose a dry day with no rain forecast for the first 24 hours for most products, because rain can wash the treatment away before it works. Avoid frost, which can make the paving slippery, and avoid very hot sunshine, which dries cleaners too quickly.
Brush and rinse
After the product has worked, use a stiff broom or brush to loosen dead moss and algae, then rinse the surface. A pressure washer saves time on larger areas, and a patio cleaner attachment gives a more even finish.
Prevent regrowth
Sweep leaves regularly, trim back overhanging branches, and fix any drainage problems that leave water standing on the surface. Treating again each autumn keeps most patios clear and safe through the winter.
A simple step-by-step routine
- Sweep off leaves, loose moss and debris so the cleaner can reach the surface.
- Pre-wet very dry paving if the label advises it, and move furniture and pots out of the way.
- Mix or measure the product as instructed, then apply evenly with a watering can, pump sprayer or mop.
- Leave it to work for the time recommended on the label, keeping pets and children off the area.
- Brush or pressure wash the loosened growth away, working in the direction of any drainage fall.
- Rinse the area and your tools, then allow the surface to dry before replacing furniture.
Why timing in autumn helps
Treating in October or early November gives the product a chance to work before the hardest frosts, and leaves you with a cleaner surface through the wettest months. Patios in deep shade often need treating twice a year, and sunny, open patios may need it less often. If algae returns very quickly, improving drainage or trimming back shading plants will help more than repeating the treatment.
Frequently Asked Questions
Is bleach a good patio cleaner?
Household bleach can lighten paving and harm plants and wildlife. It is better to use a product made for the purpose and follow the instructions.
How long does it take to work?
Some products show results in hours, while spray-and-leave treatments can take weeks. Be patient and give the product time before reapplying.
Do I need to wear protection?
Yes. Wear gloves and eye protection when mixing and applying, and read the safety information on the label.
Our Recommendation
For most patios, the Jeyes 4 in 1 is a sound, good-value choice, while the GLEAN concentrate is the better pick for larger areas. If you want something that works with minimal effort, Wet and Forget is worth the extra cost, and the budget ULTIMA-PLUS is a sensible way to treat small patches without spending much.
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