Black spots, otherwise known as lichen, tend to appear when mould and algae have settled into the pores of the patio slabs.
Despite common beliefs, jet washing does not remove these stubborn stains and using a pressure washer also damages the stonework making it more susceptible to more black lichen spores taking hold in the future.
Furthermore, the spores can be spread into unaffected areas by the force of the water.
Unsure of how to get rid of the black stains covering his garden patio slab, Steven Beedham took to the Gardening UK Facebook page to ask for “effective” solutions.
Posting a picture of the state of his patio, Steven said: “Does anyone know any effective methods to get rid of black spots on the patio?”
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While some group members suggested purchasing a popular patio cleaner on the market, many others suggested that laundry detergent can be used to remove the stains.
Emma Leary said: “I haven’t used it personally but I remember a post about using washing powder. So many people raved about it.”
Sian Williams wrote: “My boyfriend used washing powder on mine and it looks like new now.”
Sharing a picture of half her patio with black spots before cleaning and half stain-free after cleaning the patio, Alison Reader commented: “We used laundry powders and it was truly amazing.”
Nick Andrews said: “The cheapest way to make these marks disappear quickly is to use a bucket of hot water and loads of washing powder.
“Brush it in and let it soak. Then brush off after a couple of hours with water.”
Iona Matherson-long agreed and suggested that “biological” washing powder is the “best” option to go for.
Jeff Durkin wrote: “Washing powders is the best thing I’ve found apart from regular patio cleaners.
“I brush it on with water and place foam square over the top to stop it drying out, leave it overnight or longer to give it time to work, then wash off.”
Archie Solas suggested: “Biological washing powder is the way to go. Something really strong like Bold or Daz.”
Cleaning the patio slabs with washing powder is a simple and effective method. However, before cleaning the patio, clear the area and then do a fine sweep with the broom.
Many people claim that washing powder can also help to verve moss and algae from patios and paving.