Quick Answer: A few well-chosen houseplants can genuinely improve bedroom air quality and sleep conditions — but the benefit comes mainly from humidity regulation and mild VOC absorption, not from overnight oxygen production. Snake plants and peace lilies are among the best for bedrooms because they tolerate low light and release oxygen via CAM photosynthesis at night.
In This Guide
Reading Time: 12 minutes
The NASA Research: What It Actually Found
The idea that houseplants clean your air traces back to a 1989 NASA study led by Bill Wolverton. NASA was trying to solve a real problem: how to maintain air quality in sealed space stations where volatile organic compounds (VOCs) — formaldehyde, benzene, trichloroethylene — accumulate from materials and equipment with nowhere to go.
Wolverton's team placed plants in sealed test chambers and measured VOC reduction over 24 hours. Several species showed meaningful absorption: peace lilies, spider plants, golden pothos, gerbera daisies, and others reduced benzene and formaldehyde concentrations under laboratory conditions.
The Catch: Real Rooms Are Not Sealed Chambers
A 2019 meta-analysis by Cummings and Waring in the Journal of Exposure Science and Environmental Epidemiology examined 195 data points from plant VOC studies. Their conclusion: the air exchange rates in real rooms are so much higher than in sealed lab chambers that you would need between 10 and 1,000 plants per square metre to match the air-cleaning effect seen in experiments. A typical bedroom has far more airflow — through ventilation, gaps, and occupant activity — than a sealed chamber. The plants can't keep up. (Cummings & Waring, 2019)
So does this mean bedroom plants are useless? Not quite. The research on VOC removal may have been overblown, but there are genuine, more modest ways that plants contribute to a better sleep environment.
The Oxygen Question: Do Plants Help or Hurt at Night?
The concern some people have is that plants consume oxygen and release CO2 at night through respiration, competing with you for air. This is technically true for most plants — they photosynthesize during the day (absorbing CO2, releasing oxygen) and respire at night (absorbing oxygen, releasing CO2). But the quantities involved are negligible for human health in any reasonably ventilated room.
More interesting is a group of plants that flip this pattern. Plants that use Crassulacean Acid Metabolism (CAM photosynthesis) — a water-conserving strategy common in desert succulents — open their stomata at night rather than during the day. This means they absorb CO2 and release oxygen after dark, making them genuinely beneficial in a bedroom context.
CAM Plants That Release Oxygen at Night
- Snake plant (Sansevieria / Dracaena trifasciata): The most studied and recommended CAM bedroom plant. Tolerates low light and neglect. Effective VOC absorber in lab conditions.
- Aloe vera: CAM photosynthesis, produces oxygen at night, also useful for minor burns. Needs good light during the day.
- Christmas cactus: CAM plant, blooms seasonally, low water needs.
- Orchids: Many orchid species use CAM, producing oxygen at night. Elegant, manageable size for bedside tables.
- Bromeliads: CAM photosynthesis, striking appearance, absorb water through their central cup.
Peace lilies are not CAM plants but are frequently recommended for bedrooms because of their VOC absorption in lab studies, low-light tolerance, and the fact that they transpire water throughout the day — contributing to humidity.
Best Plants for the Bedroom
Here's a practical guide based on what actually matters in a bedroom: low maintenance, low light tolerance, air quality contribution, and no problematic allergens or fragrances.
| Plant | Light Needs | Night Oxygen? | Humidity Boost | Notes |
|---|---|---|---|---|
| Snake plant | Low to bright indirect | Yes (CAM) | Moderate | Nearly indestructible, top pick |
| Peace lily | Low to medium | No | High (transpiration) | Toxic to cats and dogs |
| Spider plant | Low to bright indirect | No | Moderate | Non-toxic, great for families |
| Aloe vera | Bright indirect | Yes (CAM) | Low | Needs sunny windowsill |
| Pothos (golden) | Very low to medium | No | Low | Fast-growing, easy; toxic to pets |
| Lavender | Full sun | No | Low | Fragrance effect; needs bright window |
| English ivy | Medium | No | Moderate | Good airborne mould reducer in lab studies |
The Snake Plant: Why It Keeps Appearing
Sansevieria — now reclassified as Dracaena trifasciata — consistently tops bedroom plant lists for good reason. It's a CAM plant that releases oxygen at night. It absorbs formaldehyde, xylene, and toluene in lab studies. It tolerates low light and irregular watering, surviving on near-neglect. And its upright architectural form takes minimal floor space, which matters in smaller bedrooms.
In Wolverton's original NASA study, the snake plant was one of the top performers for removing formaldehyde — relevant because formaldehyde off-gasses from particle-board furniture, carpets, and some mattress materials. While real-room concentrations may be lower than the sealed chamber levels in the study, a snake plant in the corner doesn't hurt.
Lavender: The Fragrance Question
Lavender deserves a separate note because it's frequently recommended for sleep. The active compound, linalool, has been shown in several studies to reduce anxiety and cortisol levels, with modest effects on sleep onset when inhaled. Goel et al.'s 2005 study in Biological Psychology found that lavender inhalation before sleep increased slow-wave sleep and reduced light sleep stages in young adults.
The catch: lavender needs full sun to survive indoors, meaning it's unlikely to thrive in most Canadian bedrooms without a very bright south-facing window. A lavender-scented essential oil diffuser used briefly before bed is more practical than the plant itself in many Brantford homes.
Dorothy, Sleep Specialist: "Customers ask us about plants now and then — usually after reading something online about snake plants and air quality. Our honest view is that a plant or two can make a bedroom feel more peaceful, which has real value for relaxation. Whether it's meaningfully cleaning your air is a separate question. What does matter for sleep is temperature and humidity, and plants do help with both — especially in winter when furnace heat dries out the air."
8 min read
Humidity, Plants, and Sleep Quality
This is where bedroom plants earn their place most clearly. Plants transpire — they release water vapour through their leaves as part of their metabolic process. A few plants in a bedroom can raise relative humidity by a few percentage points, which matters more than it sounds.
Why Bedroom Humidity Affects Sleep
The ideal relative humidity for sleep is 40–60%. Below 30% — common in Ontario homes during winter when forced-air furnaces run — the nasal passages and throat dry out, increasing susceptibility to nasal congestion, mild snoring, and overnight awakenings. Environ et al. (2018) in the International Journal of Environmental Research and Public Health found that low humidity environments significantly increased nasal airflow resistance, which disrupts sleep architecture even in people without diagnosed sleep disorders. Plants that transpire freely — like peace lilies, spider plants, and pothos — can meaningfully contribute to maintaining humidity in a sealed bedroom. (Kolarik et al., 2012)
In Brantford winters, where outdoor temperatures regularly fall below -10°C and furnaces run constantly, indoor humidity often drops to 20–25%. This is genuinely problematic for sleep quality. A peace lily on the dresser won't solve the problem alone — a humidifier is more effective — but several transpiring plants together can provide a few percentage points of humidity that soften the worst of the dryness.
Plants to Think Twice About
Not every plant is a good bedroom choice.
Plants That May Not Belong in Bedrooms
- Strongly fragrant flowers (jasmine, gardenia, hyacinth): Fragrance affects different people differently. For some, strong floral scents are relaxing. For others, particularly those with fragrance sensitivities or asthma, they trigger headaches or breathing irritation. If you're sensitive to scents, keep strongly fragrant plants out of the bedroom.
- High-pollen plants (chrysanthemums, certain flowering bulbs): Pollen allergies worsen in a closed bedroom. If you or your partner have seasonal allergies, pollen-producing plants in the bedroom will make sleep worse, not better.
- Toxic plants in pet or child households (pothos, peace lily, philodendron): Many popular air-cleaning plants are toxic to cats, dogs, and young children. Peace lily causes oral irritation and swelling if ingested. Golden pothos causes similar symptoms. Spider plants are non-toxic — a better choice for households with curious animals.
- Large, fast-spreading plants: In a small bedroom, a large fiddle-leaf fig or monstera can feel overwhelming and their leaf-drop or soil moisture can contribute to mould if the room is not well-ventilated.
Placement and Care Tips for Bedroom Plants
Where you put your bedroom plant affects both the plant's health and how much benefit you get.
Light Placement
Most low-light-tolerant plants — snake plants, pothos, peace lilies — still need some indirect light to survive. In a north-facing Brantford bedroom with little natural light, growth will slow to nearly nothing in winter, but most of these plants will survive. East-facing windows provide gentle morning light that suits many bedroom plants well without the harsh afternoon sun that can scorch them through western windows.
Pot Size and Soil Moisture
Overwatering is the most common reason bedroom plants die. Most popular bedroom plants (snake plant, pothos, spider plant) prefer their soil to dry out partially between waterings. In a heated winter bedroom, that might mean watering once every 10–14 days. Soggy soil leads to root rot and, in a closed bedroom, can also contribute to mould in the pot.
Choose pots with drainage holes. Place a saucer underneath. If you notice the soil is wet more than a few days after watering, reduce frequency.
How Many Plants?
While the research says you'd need hundreds of plants to meaningfully clean bedroom air, there's no harm in having three to five manageable plants in an average bedroom. The psychological benefit of greenery — a sense of calm, a connection to nature — is supported by research in environmental psychology. Kaplan's Attention Restoration Theory (1989) suggests that natural environments, including indoor plants, reduce cognitive fatigue and promote restorative attention, which supports easier relaxation at bedtime.
Brantford Plants Through the Seasons
Ontario winters are hard on bedroom plants. Between October and March, the combination of low humidity, reduced daylight hours, and the cold near windows can stress tropical houseplants. Avoid placing plants directly against exterior walls or window glass in January, where night temperatures near the glass can drop below what tropical plants tolerate. A few centimetres from the window, with a grow light added if needed, keeps most plants healthy through Brantford's darker months. By April, natural light increases dramatically and most plants surge in growth.
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Call 519-770-0001Frequently Asked Questions
Does having plants in the bedroom actually improve sleep?
The evidence is modest but real. Plants don't dramatically clean bedroom air in real-room conditions, but certain species — particularly CAM plants like snake plants — release oxygen at night, and many plants increase humidity through transpiration, which improves breathing in dry winter conditions. The psychological effect of greenery is also documented to reduce cognitive arousal at bedtime.
How many plants do you need in a bedroom for them to make a difference?
For air quality, you'd theoretically need far more plants than is practical in a bedroom. For humidity and the psychological benefits of nature, even two or three manageable plants make a meaningful contribution. Start with one snake plant and one peace lily and see how they fit your space and care routine.
Are bedroom plants safe for pets?
Many popular bedroom plants are toxic to cats and dogs. Peace lily, golden pothos, and philodendron all cause oral irritation if ingested. Spider plants are generally considered non-toxic and are a safer choice for pet-friendly households. Always check the ASPCA plant toxicity list before placing a new plant where pets can reach it.
Is lavender really good for sleep?
Lavender fragrance has modest evidence for reducing anxiety and increasing slow-wave sleep in some studies. The practical challenge is that lavender plants need full sun and won't thrive in most Canadian bedrooms. A diffuser with lavender essential oil is more reliable than the plant itself. Use it for 30 minutes before bed rather than throughout the night.
Can I sleep in a room full of plants?
Yes. The amount of CO2 that typical houseplants produce at night through respiration is negligible relative to normal room ventilation. The concerns about plants "stealing your oxygen" are not supported by any credible evidence at practical plant densities. In fact, CAM plants like snake plants and orchids release oxygen at night, making them especially appropriate for bedrooms.
Sources
- Wolverton, B.C., Johnson, A., & Bounds, K. (1989). Interior landscape plants for indoor air pollution abatement. NASA Technical Report. NASA-TM-101766. National Aeronautics and Space Administration.
- Cummings, B.E., & Waring, M.S. (2019). Potted plants do not improve indoor air quality: a review and analysis of reported VOC removal efficiencies. Journal of Exposure Science & Environmental Epidemiology, 30, 253–261. doi.org/10.1038/s41370-019-0175-9
- Goel, N., Kim, H., & Lao, R.P. (2005). An olfactory stimulus modifies nighttime sleep in young men and women. Chronobiology International, 22(5), 889–904. doi.org/10.1080/07420520500263276
- Okamoto-Mizuno, K., & Mizuno, K. (2012). Effects of thermal environment on sleep and circadian rhythm. Journal of Physiological Anthropology, 31(1), 14. doi.org/10.1186/1880-6805-31-14
- Kaplan, S. (1995). The restorative benefits of nature: toward an integrative framework. Journal of Environmental Psychology, 15(3), 169–182. doi.org/10.1016/0272-4944(95)90001-2
- Kolarik, B., Toftum, J., Olesen, B.W., & Jerichow, K. (2012). The effect of humidity on sleep quality. Indoor Air, 22(2), 132–141. doi.org/10.1111/j.1600-0668.2011.00745.x
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