It’s true — it was all a misunderstanding. Houseplants don’t clean indoor air.

Gardenologists love busting gardening myths. From the fallacy that Epsom salts are the end-all-be-all for your plants to cinnamon from your pantry as a fungicide, there is a lot of hogwash out there on the internet.

Today, we are taking on one of the most prolific gardening myths we’ve seen: that houseplants clean the home’s air of indoor pollutants.

The “houseplants clean indoor air” bandwagon

Oh, it started innocently enough, but the nursery industry and others with a vested interest took specific information, made it general and created a myth.

From major websites, such as HGTV, to smaller gardening sites, they seem to have all just blindly followed along:

• “Discover the top 10 plants that aid in the removal of pollutants”
• “44 Air Purifying Indoor Plants”
• “tropical houseplants clean indoor air of pollution” (from Almanac.com of all places)
• “Air Purifying Houseplants”

No doubt you’ve seen all of these and more. ALL of them come from sites that are not in any way science-related, written by garden writers, gardeners, or generalists.

But, have you seen these?

• “Massive Review Confirms House Plants Aren’t Actually ‘Purifying’ The Air in Your Home”
• “The science is clear: Indoor vegetation doesn’t significantly remove pollutants from the air”
• “A Garden Myth Is Born – Plants Don’t Purify Air”
• “What Indoor Plants Clean the Air Best? None of Them”

The Birth of the Myth

“A critical review, drawing on 30 years of research, has once again found that houseplants have little – if any – real value as air removers,” claims Carly Cassella at ScienceAlert.com.

That’s how long this myth has persisted – THREE DECADES.

It all started in 1989, with the release of a joint study by the National Aeronautics and Space Administration (NASA) and (are you ready?) the Associated Landscape Contractors of America.

No agenda there, right?

Titled “Indoor Landscape Plants for Indoor Air Pollution Abatement,” the report was naturally picked up by the media (who apparently lacked fact checkers even 30 years ago). It didn’t help that one of the scientists, who refuses to be interviewed, released a commercially palatable article claiming to teach folks “How to Grow Fresh Air: 50 Houseplants That Purify Your Home or Office.”

So, what’s the problem with the houseplant study?

“Wolverton [the NASA scientist] measured whether houseplants could remove VOCs from an airtight laboratory environment. “But a home is not a hermetic chamber. It has open windows and doors, drafts and leaks, and much more clutter,” suggests Robinson Meyer at TheAtlantic.com.

Michael Waring, an engineering professor at Drexel University asked Meyer to imagine an office that measures 10 feet by 10 feet by eight feet.

“You would have to put 1,000 plants in that office to have the same air-cleaning capacity of just changing over the air once per hour, which is the typical air-exchange rate in an office ventilation system,” Waring said.

That’s 10 plants per square feet of office space, according to Meyer. And, what does that look like? An office with no space for furniture, a living room without a sofa and coffee table.

So, if houseplants don’t clean indoor air, what does?

Open the windows, say the scientists who conducted the tests.

It’s frightening how quickly folks take what they read on the internet as fact without question. When you read something, ask yourself:

• What are the writer’s qualifications?
• Does the writer have an ulterior motive or an agenda?
• Where did he or she obtain the information? If there are no links to credible sources, your b.s. meter should be on high alert.

Houseplant enthusiasts and urban jungle dwellers don’t need an excuse to grow houseplants. We love them. Some of us are obsessed by them.

Who cares if they don’t clean the air?