Experts warn against this popular patio cleaning hack – here's why

This ketchup trick is trending online – but experts are talking about it for all the wrong reasons

stone patio with wooden outdoor dining furniture
(Image credit: Robert Sanderson/Future)

The arrival of spring marks the start of garden party season, so it's that time of the year when you may be dusting down your patio for celebratory times ahead. It is unsurprising, therefore, that the question of how to clean a patio is trending across social media, where some patio owners are using an unconventional tool as a cleaning solution: ketchup. 

The viral patio idea is making waves on social media, where cleaners have praised ketchup's power to remove rust, dirt, and algae. However, despite its success in these areas, experts have warned that this hack may be doing more harm than good. 

Here's why you should keep your condiments away from your paving stones – and what you should use instead. 

Why you should avoid using ketchup on your patio 

modern patio with pond and seating area

(Image credit: Ian Lamond/Alamy Stock Photo)

Cass Heaphy, the digital director at Paving Direct (opens in new tab), explains that ketchup is a vinegar-based condiment (usually about 1/3 by volume of the ingredients), meaning it will cause acidic damage to your natural stone or concrete paving. 

'Limestone, sandstone, and Portland cement concrete are all vulnerable to chemical erosion and corrosive damage from acids, so any acid-based liquid will likely corrode and damage the stone and concrete of the patio,' he says. 'My recommendation is, do not do this as it will likely damage your patio.'

The expert adds that, alongside the acidic damage, using ketchup may also leave tiny cavities in the natural stone and concrete and potentially leave pigments and staining when you to hose it off.

'I cannot 100% vouch for the latter, but that ketchup's vinegar content will damage sandstone, limestone, and concrete paving, I am 100% certain,' he adds. 

Valencia teak day bed from Jo Alexander on patio in spring

(Image credit: Jo Alexander)

Fantastic Services' (opens in new tab) garden specialist, Pol Bishop, also warns against using the popular ketchup trick on your concrete exterior. 'Please remember to avoid using a detergent with any acid if you have a concrete patio,' he adds. 'The ketchup trick is not a good idea for this situation.'

So what should you opt for instead? Cass suggests that the best patio cleaner is alkaline-based – while specialist patio cleaning products offer the best chance of success. 

Alternatively, we're investing in one of these best pressure washers to ensure our patio is spotless for (possibly) the first garden party of the year. The only thing left to think about is the playlist. 

Megan is the News and Trends Editor at Homes & Gardens. She first joined Future Plc as a News Writer across their interiors titles, including Gardeningetc, Livingetc, and Real Homes. As the News Editor, she often focuses on emerging microtrends, sleep and wellbeing stories, and celebrity-focused pieces. Before joining Future, Megan worked as a News Explainer at The Telegraph, following her MA in International Journalism at the University of Leeds. During her BA in English Literature and Creative Writing, she gained writing experience in the US while studying in New York. Megan also focused on travel writing during her time living in Paris, where she produced content for a French travel site. She currently lives in London with her antique typewriter and an expansive collection of houseplants.