Gardening pros reveal the real reason your patio is covered with ‘green slime’ & the 10 best ways to get rid of it
AN outbreak of unsightly algae is being reported around outdoor areas at homes across Britain.
People’s fences, patios, decking and even walls are excessively covered in the brightly coloured organism.
Two-thirds of Sun readers say the algae in their yards and gardens is worse than last year.
It means professional jet-washers are in high demand, with companies charging as much as £150 a time to blitz patios and outdoor furniture.
Gardening experts attribute the explosion to the weather conditions of the past few months.
Guy Barter, chief horticulture adviser for the , says: “October to March has been the wettest for that period on record, so it’s no surprise that there is a lot of algae, especially as the weather has been mild too.
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“It particularly favours the prolonged drizzle we’ve been having.
“As we expect winters to become milder due to climate change, it’s likely we could see more of this type of algae growing.”
He says the “green slime”, part of the same family as seaweed, is essentially a plant without roots.
Guy adds: “This means it finds it hard to get water, which is why you’ll typically find it in shady places where the drainage is poor and there is a lack of airflow.
"It’s a tough old thing and if there is an opportunity to grow, it will find it.”
Although unsightly, Guy says it is not harmful to humans or wildlife, but its slipperiness is what can cause us grief.
He adds: “It will typically affect paving, especially if it is in the shade or near overhanging branches.
“It will attack any surface. There will almost certainly be some on the lawn and in the soil — the sort of places where you get moss or lichen.
“You might see it on wooden fences and posts, or roofs. It won’t cause damage as it doesn’t have roots, but it could be a sign that things are already rotten.
“If you are concerned about traversing slippery surfaces, get some sand sprinkled on the area.”
Emma Young, 37, a marketing manager, has spent hours tackling the green invader in her garden in Scunthorpe, Lincs.
He says: “Demand for everything — roofs, patios, driveways, guttering — has been unprecedented. My colleagues with 20 years’ experience in the industry say the same.
“Some of them will be more effective than others, depending on the severity of the stains.
“But keep in mind that algae is an organism that’s survived many destructive conditions since before the dinosaurs. It’s very difficult to control.”
Vinegar solution
Create a solution of equal parts distilled white vinegar and water in a spray bottle. Apply generously, allow to sit for 15-20 minutes, scrub with a stiff-bristled brush and rinse.
Baking soda and water
Mix one cup of baking soda with approximately four litres of water until it forms a paste. Apply, leave for at least 30 minutes, scrub and rinse.
Lemon juice
Cut a lemon in half and rub the cut side over the stains. Leave to sit for 10-15 minutes, scrub and rinse.
Lime powder
Sprinkle this organic product onto the algae spots, leave to sit for two hours and wash it away.
Sharp sand
This is especially effective for patios. Mix with water and use a brush or broom to scrub the affected surface.
Ponds are another place where algae can be a problem, as it can block sunlight for other plants and interfere with the oxygen available for fish and other creatures.
“We put barley straw into the ponds at the RHS gardens and as it rots, it produces hydrogen peroxide, which suppresses the algae without doing any other harm,” says Guy Barter.
“You can buy it from garden centres and specialist pond suppliers.
“A more expensive option for ornamental ponds is ultraviolet cleaners, or add a special dark water dye, which cuts out the light and stops the algae growing without harming the fish.
“Growing water lilies to cast shade and keeping the number of fish low – because their droppings can enrich the water – will also help.”
But algae season should end soon, according to Guy.
He says: “As the air gets drier and the rain hopefully gets less, the algae won’t become a problem until next November.
“In the meantime, think about tackling the underlying cause, with better drainage and airflow, using a wood preservative treatment.
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"Or get covers for furniture to block out the light and water next winter. Ultimately, it’s something we just have to live with.”
Patio saviours for your anti-algae toolkit
- Titan TTB1300PRW High Pressure Washer, £59.99, Screwfix
- Wet & Forget Mould, Lichen & Algae Remover 2L, £16, Wickes
- Newman & Cole Long Handle Patio Brush, £11.99, Amazon
- Liquipak Softwash Surfactant 5L, £24.29, B&Q
- Patio Magic! Concentrate 5L with Battery Operated Power Sprayer, £25.60, Argos