The Air Purifying Spider Plant: What’s Real and What Isn’t
The air purifying spider plant has been a popular houseplant claim for decades — but how much of it is actually true?
Quick answer: Spider plants do remove certain indoor air pollutants, but their real-world impact is far more modest than most articles suggest.
| Claim | Verdict |
|---|---|
| Removes formaldehyde and VOCs | ✅ True, but mainly in sealed lab conditions |
| 95% toxin removal in 24 hours | ✅ True in NASA’s sealed chamber tests — not in your living room |
| Replaces a mechanical air purifier | ❌ No — plants complement, not replace, HEPA filtration |
| Removes mold spores and allergens | ❌ No solid evidence for biological contaminants |
| Boosts mood, humidity, and wellbeing | ✅ Yes — these benefits are real and well-supported |
Here’s the honest picture: NASA’s famous 1989 study confirmed that spider plants could pull toxins like formaldehyde out of the air. That’s real science. But those tests were done in sealed Plexiglas chambers — nothing like the air-exchanging, drafty, lived-in spaces most of us call home.
That gap between lab and living room is where a lot of the confusion starts.
People who place spider plants in their homes do report real benefits — fewer headaches, less stuffiness, a general sense of calm. Whether that’s down to measurable air chemistry or simply the well-documented mood lift of having greenery around is harder to say.
What is clear is that the story is more nuanced than “NASA says plants clean your air.”
The NASA Legacy: What the 1989 Study Actually Proved
To understand the reputation of the air purifying spider plant, we have to travel back to the late 1980s. NASA was looking for ways to keep the air clean for astronauts in space stations—environments that are essentially airtight cans. NASA conducted a study that changed how we look at our living rooms forever.
In these experiments, scientists placed various houseplants, including the Chlorophytum comosum (our friendly spider plant), into sealed Plexiglas chambers. They then pumped in specific chemicals known as Volatile Organic Compounds (VOCs). The results were staggering: spider plants removed roughly 95% of formaldehyde from the chamber in just 24 hours. They also showed a knack for filtering out benzene and xylene.
However, we need to talk about the “fine print.” Your living room is not a sealed Plexiglas box. In a typical home, air is constantly moving. Doors open, windows leak, and your HVAC system cycles air through the house. This “air exchange” happens much faster than a plant can scrub the air. While there are many plants that filter toxins from the air, the sheer speed of air movement in a modern home often outpaces the biological work of a single plant.
How the Air Purifying Spider Plant Targets Toxins
So, how does it actually work? It isn’t magic; it’s biology. Through a process called phytoremediation, the spider plant “breathes” in pollutants through tiny pores in its leaves called stomata. Once inside, the plant breaks down these chemicals or moves them down to the root system.
The air purifying spider plant is particularly effective against:
- Formaldehyde: Found in plywood, particleboard, and some carpets.
- Carbon Monoxide: A byproduct of gas stoves or fireplaces.
- Nitrogen Dioxide: Often present in homes with gas appliances.
- Xylene and Toluene: Common in paints, adhesives, and permanent markers.
By absorbing these substances, the plant contributes to the health benefits of plant air filters, which can lead to fewer “sick building” symptoms like itchy eyes or throat irritation.
The Role of Soil Microbes in Air Purification
Here is a secret most people miss: the leaves aren’t doing all the work. In fact, the soil and the roots might be the real MVPs. Research suggests that the microorganisms living in the potting mix—bacteria and fungi—are responsible for a huge chunk of the toxin breakdown.
These microbes “eat” the pollutants that the plant transports to its roots. To help them do their job, we recommend using plants to improve indoor air circulation by choosing porous pots like terracotta. Terracotta allows air to penetrate the root-soil zone more effectively than plastic, giving those hardworking microbes more “food” to process. Keeping the soil aerated and ensuring the plant isn’t drowning in stagnant water is key to maintaining this microscopic cleaning crew.
Real-World Reality Check: How Many Plants Do You Really Need?
If you want to move the needle on air quality in a standard home, one plant on a bookshelf isn’t going to cut it. This is where the experts tend to disagree.
Bill Wolverton, one of the original NASA researchers, suggests that about 60 plants could effectively purify the air for an entire house. On the other hand, John Girman of the EPA has suggested the number might be closer to 700 plants to match the air-cleaning power of a mechanical system. Imagine trying to get to your coffee maker while navigating a jungle of 700 pots!
Since most of us don’t live in greenhouses, we have to look for natural ways to boost indoor air quality that are actually practical. A great strategy is to focus on your “personal breathing zone.” This is the six-to-eight cubic feet of air immediately surrounding you while you sleep or work. By placing a few spider plants on your nightstand or your desk, you are cleaning the air exactly where you are inhaling it.
| Expert/Source | Recommendation | Goal |
|---|---|---|
| Bill Wolverton (NASA) | 2-3 plants (8-10″ pots) per 100 sq. ft. | Measurable VOC reduction |
| John Girman (EPA) | 10 plants per square foot | Matching mechanical filtration |
| Airdog/Modern Research | 8-15 plants per living space | Holistic environmental boost |
| Mount Pilchuck Tip | Focus on the “Personal Breathing Zone” | Immediate air quality benefit |
Beyond Filtration: The Holistic Benefits of Spider Plants
While the air-scrubbing debate continues, there are other benefits to the air purifying spider plant that are undisputed. These plants are incredible for humidity control. Through a process called transpiration, they pull water from the soil and release it as vapor through their leaves. This can be a lifesaver in winter when heaters dry out our skin and sinuses.
There is also the psychological factor. Research into indoor plants for mental wellness shows that interacting with greenery reduces cortisol levels (the stress hormone). Just the act of seeing those little “spiderettes” (the baby plants) dangling from the mother plant can provide a sense of calm and accomplishment.
Furthermore, some studies suggest that spider plants can help with indoor plants that reduce dust by increasing local humidity, which causes dust particles to clump together and fall out of the air rather than floating into your lungs.
Is the Air Purifying Spider Plant Safe for Pets?
One of the best reasons to choose a spider plant over, say, a Peace Lily or a Snake Plant, is safety. According to the ASPCA, spider plants are non-toxic to both dogs and cats. This makes them one of the most popular indoor plants safe for pets.
However, you might notice your cat acting a bit… strange around them. Spider plants have a mild hallucinogenic effect on felines, similar to catnip. While it isn’t “poisonous,” if your cat treats your plant like an all-you-can-eat buffet, they might end up with an upset stomach or a case of the “zoomies.” It’s usually best to hang them in baskets out of reach—not because they’ll hurt the cat, but because the cat will definitely hurt the plant!
Maximizing Your Air Purifying Spider Plant: Care and Strategy
To get the most air-cleaning power out of your plant, it needs to be healthy. A struggling plant doesn’t “breathe” as efficiently as a thriving one. Here are our top tips for easy-care plants for home air quality:
- Lighting: They love bright, indirect light. A spot near an east or west-facing window is perfect. Too much direct sun will scorch the leaves, while too little light (a 40% reduction in toxin absorption) will make them sluggish.
- Watering: Wait until the top inch of soil is dry. They are low-maintenance air-purifying plants, but they don’t like “wet feet” (root rot).
- Dusting: This is crucial! If the leaves are covered in dust, the stomata are blocked. Wipe the leaves weekly with a damp cloth so they can continue to absorb pollutants.
- Water Quality: If you see brown tips, it might be the fluoride in your tap water. Try using distilled water or rainwater to keep them looking pristine.
- Temperature: Keep them between 59°F and 73.5°F. They are quite hardy but prefer the same temperatures humans do.
Frequently Asked Questions
Can spider plants effectively remove mold spores?
While some preliminary NASA tests suggested that spider plants could remove up to 95% of toxins including mold spores in a sealed environment, they aren’t a “cure” for a moldy house. They help by reducing local humidity through condensation control in some cases, but they cannot replace professional mold remediation or a HEPA air purifier for biological contaminants.
How many spider plants are needed per 100 square feet?
A good rule of thumb for a noticeable difference is two or three healthy plants in 8- to 10-inch pots for every 100 square feet of floor space. This density provides a measurable reduction in VOCs without turning your home into an impassable thicket.
Do spider plants produce oxygen at night?
Yes! While most plants take in oxygen and release CO2 at night, spider plants (along with snake plants) are known to continue producing oxygen after the sun goes down. This makes them one of the top air-purifying plants for bedrooms, potentially improving sleep quality and breathing.
Conclusion
At Mount Pilchuck, we believe in a balanced, holistic approach to a healthy home. Is the air purifying spider plant a magical machine that will replace your air conditioner and filters? No. But is it a valuable, beautiful, and pet-safe ally in the quest for better indoor air? Absolutely.
By combining mechanical filtration with the natural power of plants, you create an environment that isn’t just “clean,” but also vibrant and stress-reducing. Start with a few plants in your most-used rooms and enjoy the literal and metaphorical breath of fresh air they provide.
