The Truth About the Best Plants to Purify Air Indoors

There are a million articles out there about the best plants to purify air indoors. Do you believe them?

They aren’t actually wrong, but you will probably not be surprised to know that there is more to the story than “Buy These Plants and Now You Have Clean Air!”

There was probably always something that felt a little too good to be true to you, so let’s satisfy your curiosity with the truth about whether or not plants really do purify the air in your home.

Where Did the Idea of Using Plants to Purify The Air Come from?

The root of all of those articles that you see about plants to purify air come from a study that NASA did on plants and air purification.

Crazy, right?? It already doesn’t seem likely that something that NASA is studying would really have much relevance to the average homeowner in their average non-Space Station home.

But actually, it’s not all about sealed up Space Stations. It’s also about sealed up office space.

The study was done in the 80’s and it was done coming off of a period of time in the 70’s when oil and gas were super expensive and so companies spent money on sealing up their office buildings in order to save on heating expenses.

The problem with that is those super sealed up buildings had terrible ventilation and a phenomenon called “sick buildings” became a thing.

If those buildings that had been sealed so well they made people sick were a problem, then you can see how NASA would be interested in the correlation then to future hermetically sealed space stations, right?

What Did NASA Do?

The study report is actually pretty short (less than 30 pages) and not nearly as difficult to read as I imagined it would be, but the gist of the study is this.

NASA put some plants into sealed boxes, regular old plants they bought locally and kept in the potting containers and soil they came with and then injected chemicals into the boxes to see how well the plants could clean the chemicals.

They also did tests with regular old plants PLUS a neat carbon filtering system. It was never really thought the plants alone were going to do all of the dirty work. They would be just one part of a system.

And the good news is that the plants did indeed clean the air. Even the ones without the filtering system.


Big but here.

The conditions in the study are nothing at all like the conditions in our homes.

First of all, the plants were in sealed boxes meant to mimic those sealed up buildings and futured sealed up space stations.

I don’t know about you, but I don’t live like that. We have open windows almost all the time. We open and close doors on the daily and I’m sure my old home probably has more cracks and crevices than… um I have no good analogy for that.

More cracks and crevices than the Grand Canyon? We’ll go with that.

That coupled with the fact that what isn’t really talked about in the study is just how many plants would one need in order to really effectively clean the air makes me think that this study really isn’t going to hold a lot of relevance for the average household.

The summary of the study states:

Low-light-requiring houseplants, along with activated carbon plant filters, have demonstrated the potential for improving indoor air quality by removing trace or organic pollutants from the air in energy-efficient buildings. This plant system is one of the most promising means of alleviating the sick building syndrome associated with many new, energy efficient buildings.

The NASA Houseplant Study

So lots of promise for sealed tight office buildings and if the plants are using the carbon filtering thingamajig. But for the average household? Not so much air purifying is really happening.

Now I Feel Bad for Dispelling the Air Purifying Plant Myth

First of all, it’s not like the plants are doing nothing for your air in your home. There is definitely a tiny bit of purifying happening with your houseplants. It’s just what they do.

And the more plants you have, the more they will help with purifying the air, so there’s that! Buying more plants will technically help. You can keep telling your husband that.

But the moral of the story is that while your houseplants might not be doing quite as much to purify your air as you thought, they are still improving your life in other ways.

They are beautiful.

They offer you the opportunity to provide care to a living thing. A living thing that doesn’t talk back. Or pee on your rugs. Or leave it’s empty drinking glasses all over the house.

We are nurturers and creators by nature and houseplants are a wonderful way to nurture and create.

The Houseplants from the NASA Study

Curious about what houseplants NASA used in the study? Here’s the twelve houseplants NASA used in the study.

#1 Bamboo Palm

Best Plants to Purify Air Indoors

Water: Water when the surface of the soil feels dry.

Light: Low to moderate light indirect light.

#2 Chinese Evergreen

Water: Water when the top two inches of soil are dry.

Light: Low light to bright indirect light. Just avoid direct light.

#3 English Ivy

Water: Let 1/2 of the soil dry out before a good soaking.

Light: Medium to low light, but don’t expect those variegated leaves. You’ll need bright, indirect light for that.

#4 Ficus

Water: Soil should be kept moist, but not dry or drenched, at all times.

Light: Bright indirect or filtered light.

#5 Gerbera Daisy

Water: Water when the top inch of soil is dry.

Light: Bright light.

#6 Janet Craig

Water: Allow the soil to dry slightly before watering.

Light: Low light

#7 Marginata

Water: Water when first inch of soil is dry

Light: Medium light, but can tolerate low light

#8 Mass Cane

Water: Allow the surface of the soil to become dry before water

Light: Moderate bright light or low light

#9 Mother-in-law’s Tongue

Water: Allow to dry out between waterings. Do not overwater.

Light: Low to moderate to bright indirect light.

#10 Peace Lily

Water: Water when the top inch of soil is dry.

Light: Low light (this doesn’t mean “no light”. It will need some light to produce a flower).

#11 Pot Mum

Water: Water when the top inch of soil is dry.

Light: Bright, filtered light

#12 Warneckei

Water: Soil should be evenly moist, but do not overwater.

Light: Low light to bright filtered light.

Now You Know the Truth About the Best Plants to Purify Air Indoors

Love your plants just as much as you did before read this, ok?

They are still working hard even if the air purifying is really not what everyone has cracked it up to be.