The news is shocking enough to render a weeping fig inconsolable.
Despite their reputation as indoor pollution busters, new research has confirmed that, when it comes to purifying our fug-laden homes, houseplants are useless.
Unless you transform your living room into Tarzan’s lair, that is. Only then will you experience the clean-breathing benefits that have long been associated with ferns, palms and spider plants.
For, says Michael Waring, a professor of architectural and environmental engineering at Drexel University in Philadelphia, you need somewhere between ten and 1,000 plants — depending on the size and species — per square metre to achieve just the same ‘air cleaning’ effect as opening a few windows.
This will, of course, be a tragic development for millennials, whose fervent hoovering up of houseplants has sparked a potted plant boom unprecedented since the Seventies.
Despite their reputation as indoor pollution busters, new research has confirmed that, when it comes to purifying our fug-laden homes, houseplants are useless
Sold the lie that houseplants are both stylish (really?) and good for the environment (oh come on!), millennials now buy more cheese plants, aloe veras, bamboos and the like than any other generation, accounting for a third of all sales.
Typically for selfie-obsessed 20-somethings, the houseplant resurgence has little to do with green fingers and far more to do with provoking ‘green envy’ online.
Clean eating was so 2018. Today’s Instagrammers are now into ‘clean breathing’, with the hashtag ‘houseplants’ bringing up more than 2.5 million posts on the photo-sharing app.
Even that much lampooned hippy standard of the Seventies indoor-jungle look, the rubber plant, is bouncing back. Rattan baskets and hanging planters are also in vogue again. The macramé army has returned — but is it here to stay?
Professor Waring, drawing upon 30 years of research, isn’t so sure. Indeed, he maintains that plants are simply too slow at filtering out common airborne toxins known as volatile organic compounds (VOCs) such as benzene.
Released into the atmosphere after burning wood, coal and gasoline, these chemical compounds can cause eye, nose and throat irritation, frequent headaches and lung cancer.
In other words, not filtering them out is a pretty big flaw.
Professor Waring puts the blame for millennials’ misplaced potted plant dependence on a rather unlikely organisation: Nasa.
In the Eighties, Nasa engineers were determined to find out how to stop VOCs clogging up the air on space stations. Of course, if it gets stuffy in space, you can’t just open a window. And so in 1989 they carried out a number of tests to see if plants could do the job. But while the experiments were, for the most part, a success, pot plant peddlers who then used the findings to market their wares failed to explain that the tests were conducted in sealed laboratories. These sterile chambers have nothing in common with the swirling atmosphere in most homes — and plants simply don’t catch wafting air fast enough to efficiently purify it.
That’s not to say that houseplants are completely useless air-cleaners. The mere act of photosynthesis — the chemical process that produces food for the plant — removes carbon dioxide and returns oxygen to the air.
And outdoors, plant roots are able to absorb toxic heavy metals like lead into their cells.
Meanwhile, even if plants aren’t the fantastic air cleaners as once thought, psychologists still rave about the myriad mental uplifts we get from simply having green living things around us.
Dubbed ‘biophilia’, they say that merely looking at green leafy plants helps to boost our mood, making us feel physically better and think more creatively.
Meanwhile, even if plants aren’t the fantastic air cleaners as once thought, psychologists still rave about the myriad mental uplifts we get from simply having green living things around us
All of this might explain why recent tests show that having plants around the home help us to get along better with our companions.
Fancy that? They might even help to clear the air — if not clean it — after domestic rows . . .
Unless of course, your house plants decide to mysteriously kill themselves off — just like the expensive parlour palm that I installed in our living room last year, and is now currently committing suicide one leaf at a time. With ‘fronds’ like that, who needs enemies?
Nevertheless, an entire industry has burgeoned around identifying particular house plants for specific air-cleaning tasks around the home.
Country Living’s website, for example, claims that the English ivy is a perfect plant for a bathroom because ‘it is particularly effective at reducing airborne faecal particles’. Charming.
At least plants are generally cheaper than the electronic air purifiers often found in high-tech homes. The clean-breathing craze has also sent sales of these soaring, with the global market expected to be worth £6.2 billion by 2024. Some, such as the trendy Molekule (predictably endorsed by Gwyneth Paltrow’s lifestyle website Goop), promise to ‘actually destroy’ pollutants ‘at the molecular level’.
Even if that were scientifically credible, the £560-plus price tag is enough to make you wheeze.
By comparison, a broad lady palm, which horticulturists claim to be ‘one of the few plants that can help reduce levels of ammonia found in a range of cleaning products’, seems a snip at £350 for a full-grown sample.