How to Effectively Remove Green Mould – Tips and Tricks

You spend time creating a beautiful garden space. But there’s one obstacle that becomes almost impossible to overcome: green mould!

Indeed, almost as certain as death or taxes, green mould covers your patio tiles and concrete floors. And it doesn’t just look unsightly — it can be a serious slip hazard. 

So, this article is about removing and preventing green mould and using home remedies to keep your garden looking gorgeous and safe. Removing the green problem the green way, if you will.

Let’s get started!

What is green mould, and how does it appear?

Green mould forms as an amalgam of algae, moss, and lichen. It forms on outdoor surfaces, such as roofs, windows, terraces, pavements, walls, garden furniture, and fences. 

As the name suggests, most green mould is green but can also be brown, black, or yellowish. 

The mould develops due to moisture, nutrients, and some exposure to daylight. All algae, moss, and lichens need water to grow — and this moisture is easy to find in the garden. 

Green mould in shady places

You’re most likely to see garden mould in the shade because ultraviolet (UV) sunlight kills most spores, making it difficult for mould to develop in full sun. 

So, look for green mould in poorly ventilated, shady areas. The nutrients come from organic substances, such as decomposing leaves and even dust, which accumulate on surfaces, transmitted through the air. 

Why you should remove green mould from your garden

• Safety — green mould makes surfaces slippery, especially decking. This poses a safety risk, particularly on steps, pavements, and terraces. 
• Surface damage — green mould doesn’t actually penetrate hard surfaces like marble or glass. However, it can seep into wood, potentially holding moisture within it, causing it to rot. While most green moulds will simply wipe away, some will discolour some surfaces. 
• Aesthetics — green mould looks ugly and gives the impression you’re neglecting your garden. 
• Hygiene — green mould can be hazardous to your health. It’s not so bad outside, but it’s a significant health problem if it develops inside, as it can harbour bacteria and cause respiratory problems. 

Therefore:

Treat removing green mould as a garden priority and an essential part o your garden care programme. 

Preventing mould

Several approaches help prevent mould in your garden:

• Regular cleaning of outdoor surfaces can help prevent mould development — focusing specifically on shady areas. 
• Good ventilation of shady areas or affected surfaces regulates moisture and can prevent mould formation. Trim your grass away from fences and walls, and leave plenty of space between your bedding plants. Avoid stacking garden furniture in shady areas. 
• Encourage reflected light. If it’s a shady area of your garden, cut back vegetation that may be restricting the light. 
• Impregnate surfaces with exterior anti-mould paint. This can brighten up your darker spaces while adding additional protection.

Home remedies — pros and cons

I’d always recommend environmentally-friendly products for your garden to help protect your soil and wildlife. 

So, try these approaches:

• Vinegar — create a solution of half and half vinegar and water, and apply it to affected surfaces. Leave it for half an hour, then wash it away thoroughly. 
• Baking soda — make a paste from water and baking soda. Apply it to the affected surfaces. Leave it for 30 minutes, then scrub it with a brush and water. 
• Citric acid — mix citric acid with water (1:10). Apply it and leave for 30 minutes (there’s a common theme here!). Then rinse with warm water. 
• Saltwater — mix salt and water (1:1). Again, leave for 30 minutes, then rinse with a brush and water. 

Advantages of home remedies

Home remedies use natural ingredients, which are less likely to damage the environment. They’re also generally cheaper than buying professional cleaning products and are straightforward to use. 

Disadvantages of home remedies

Some home remedies might not work as well as chemical cleaning agents, especially if you’re treating an area that has suffered years of green mould growth. 

Some home remedies require a little more elbow grease than chemical products. However, you’re helping protect the planet, so that’s a cause worth a little extra work, surely. 

Have you discovered other pests and nuisances in your garden? Check out our articles:

Using chemical cleaning products

If you use chemical green mould removers, ensure you read the instructions thoroughly. Wear protective clothing, such as gloves, eye protectors, and face covers, as some chemicals can be dangerous to inhale. 

Make sure the chemical is suitable for the surface

Some chemicals can damage surfaces, such as wood or paint. So, ensure the product is suitable for the treatment surface. 

And always follow the manufacturer’s instructions in the letter!

How to use chemical cleaners

Again, read the specific instructions. However, most chemical cleaning products work by spraying affected surfaces and leaving them to break down the mould before rinsing or brushing them away. 

Always rinse surfaces thoroughly with water to remove all detergent residues. And if necessary, you can apply a follow-up treatment to prevent the mould from returning. 

Can I remove the green mould with a high-pressure washer?

A pressure washer can remove green mould effectively. However, consider the surface you’re cleaning — you could damage it. 

Follow these words of caution for this approach:

• Pressure washers can damage wood and some masonry. So, make sure you test a less conspicuous area first. 
• Wear a face mask when pressure washing. You run the risk of throwing mould spores into the air. This can present a health risk. 
• Pressure washing may remove the green mould, but it won’t prevent it from returning. Some cleaning agents are more thorough and long-lasting. 
• Pressure washing consumes a lot of water. 

FAQs

Ready to get started?

I hope I’ve given you a good idea of how to tackle green mould in your garden. But if you have any questions, don’t hesitate to ask. 

Alternatively, check out our comprehensive Help & Advice section for all your garden and lawn questions. 

Thanks for reading! 

Louis Hooft

Founder & Lawn expert

Introducing Louis Hooft, the founder of MOOWY and your reliable expert. With a profound love for stunning lawns and extensive experience in garden maintenance, Louis is here to assist garden enthusiasts in achieving a greener and livelier outdoors than ever before. Count on Louis for invaluable tips, clever tricks, and top-notch products to make your garden flourish!