Indoor plants lower anxiety.
The claim
Indoor plants are living greenery brought into rooms where people spend time: potted plants on a desk, a green wall, flowers and foliage in a recovery room. They lower anxiety for the people who share the space. The effect shows up most in high-stress settings such as hospital rooms and care homes, where patients who have plants nearby report calmer feelings and less tension than those in bare rooms. It also holds in ordinary interiors and for older adults recovering from a stressful task.
The findings
Kuo (2025) pooled horticultural interventions and found a large drop in anxiety, with a Hedges' g of 0.702 (95% CI 0.341 to 1.062). The same synthesis reported gains in depression, cognition, social function and quality of life.
In experiments that watched people recover from a stressor, Yin (2019) found that participants in rooms with greenery calmed down more fully than those in bare rooms, measured as lower stress and anxiety. Lohr (1996) added plants to an interior and saw systolic blood pressure fall by one to four units alongside quicker reaction times. In hospital settings, Park (2009) and Park (2008) found that patients in rooms with plants and flowers rated their pain, anxiety and fatigue lower, took fewer analgesics and had shorter stays. Beukeboom (2012) found posters of plants produced the same calming effect as live ones.
Certainty
Kuo (2025) sets the anxiety figure at a confidence interval clear of zero (0.341 to 1.062), and the supporting work spans controlled recovery experiments, hospital field studies and several syntheses. Twelve studies stand behind this factor. The hospital results from Park (2008), Park (2009) and Khan (2016) come from patient settings where anxiety runs high, and the laboratory recovery studies by Yin (2019) and Xiaoxue (2024) show the same direction under controlled exposure. What holds the certainty short of complete is that much of the strongest effect sits in clinical and care populations, so the size of the drop in an ordinary office or home is less firmly pinned down.
In practice
A room can add live plants and expect anxiety to drop for the people who use it. The clearest gains come where stress starts high, such as a hospital or care setting, and where symptoms are more severe to begin with. The effect does not need weeks to show. Yin (2019) found the calming response begins as soon as someone is exposed and peaks within the first four minutes of recovery, so even a short stay in a planted room registers a benefit. Where an intervention runs past eight weeks, Kuo (2025) found the effect grows larger still, so a space meant to support recovery over time gains more from keeping plants in place than from a brief placement. Because Beukeboom (2012) found posters of plants worked as well as live ones, a setting that cannot maintain living greenery, such as a ward with infection controls or low light, can substitute plant imagery without giving up the calming effect. The gains are best established in clinical and care populations, so treating an ordinary office or home as certain to see the same size of drop goes beyond what the evidence pins down.
Dose and thresholds
The recovery is fast. Yin (2019) found physiological calming begins right after exposure and is strongest in the first four minutes of a six-minute recovery window, so much of the benefit lands early. Over longer horizons Kuo (2025) found in subgroup analyses that people with more severe baseline symptoms gained more, and interventions running past eight weeks produced stronger effects.
The mechanism
Exposure to greenery quiets the sympathetic nervous system. Lee (2015) traced this in people who handled indoor plants: their sympathetic activity and diastolic blood pressure dropped, and they reported feeling soothed and comfortable. The body shifts out of the stress response, and the felt anxiety falls with it.
What each profession does with this factor.
- ArchitectIndoor plants lower anxiety
- Asset managerNo certification premium attaches to the plants or the water feature
- Corporate real estateOffice plants show no measured productivity gain per head
- Developer and investorNo study ties a rent premium to the plants inside
- HR and workplaceOffice plants did not raise measured productivity in field trials
- MarketingGreenery supports a calm claim but not a productivity claim
- Workplace strategistIndoor plants do not raise measured productivity in the field
The Built Review. TBR-F-1187 (v1): Indoor plants lower anxiety. https://thebuiltreview.com/factors/indoor-plants-anxiety Licensed CC BY 4.0.
More from these studies
30 studysheets from 7 of the studies above
Some state this factor, the rest are what else those papers found.
g = 0.806
horticultural therapy may improve social functioning
Horticultural therapy improved social function in individuals with depressive disorders, but evidence certainty is low
Yi-Zhen Kuo et al., 2025, Complementary Therapies in Medicine
g = 1.050
horticultural therapy may reduce depression symptoms, but evidence quality is low
Horticultural therapy showed a large pooled effect on depression symptoms in a meta-analysis of 13 small trials, though evidence certainty was rated low
Yi-Zhen Kuo et al., 2025, Complementary Therapies in Medicine
g = 0.947
horticultural therapy is linked to better quality of life, but evidence quality is low
Horticultural therapy showed a large pooled effect on quality of life in individuals with depressive disorders, though the underlying evidence is of low certainty
Yi-Zhen Kuo et al., 2025, Complementary Therapies in Medicine
g = 0.702
horticultural therapy may reduce anxiety, but evidence is preliminary
Horticultural therapy showed a moderate-to-large reduction in anxiety in individuals with depressive disorders, though evidence certainty is low
Yi-Zhen Kuo et al., 2025, Complementary Therapies in Medicine
g = 0.816
horticultural therapy may improve cognitive function
Horticultural therapy was associated with a large improvement in cognitive function in individuals with depressive disorders, though the evidence quality is low
Yi-Zhen Kuo et al., 2025, Complementary Therapies in Medicine
-4.5 mmHg
greater fall in diastolic blood pressure than in the office without plants
An office with indoor plants produced a 4.5 mmHg greater fall in diastolic blood pressure during stress recovery
Jie Yin et al., 2020, Environment International
−6.5 mmHg
diastolic blood pressure was lower after plant transplanting than after computer work
Diastolic blood pressure is significantly lower after plant transplanting than after computer work
Min-sun Lee et al., 2015, Journal of Physiological Anthropology
plant transplanting produced lower sympathetic nervous system activity than computer work
Indoor plant transplanting suppresses sympathetic nervous system activity compared to computer work
Min-sun Lee et al., 2015, Journal of Physiological Anthropology
parasympathetic activity did not differ between plant transplanting and computer work
Parasympathetic activity (logHF) showed no significant difference between plant and computer tasks
Min-sun Lee et al., 2015, Journal of Physiological Anthropology
-6.5 mmHg
lower diastolic blood pressure after transplanting plants than after computer work
Transplanting indoor plants lowered diastolic blood pressure by 6.5 mmHg compared with computer work
Min-ja Lee et al., 2015, Journal of Physiological Anthropology
45%
nearly half of plant-ward patients preferred cut roses above all other plants and flowers
Cut roses were the single most preferred plant type among surgical patients in a plant-decorated hospital ward
Muhammad Ali Khan et al., 2016, The Pakistan Journal of Agricultural Sciences
+44%
more patients had only mild anxiety in the plant ward than in the control ward
Indoor plants significantly reduced anxiety intensity in post-surgical hospital patients
Muhammad Ali Khan et al., 2016, The Pakistan Journal of Agricultural Sciences
+26%
more patients behaved in a friendly way toward others in the plant ward
Patients in plant-decorated hospital wards showed more friendly and socially engaged behaviour
Muhammad Ali Khan et al., 2016, The Pakistan Journal of Agricultural Sciences
+34%
more patients reported an elevated mood in the plant ward than in the control ward
Patients in plant-decorated wards were significantly more likely to report an elevated mood
Muhammad Ali Khan et al., 2016, The Pakistan Journal of Agricultural Sciences
+30%
more patients rated their hospital stay as calming and soothing in the plant ward
Patients with indoor plants were substantially more likely to rate their hospital stay as calming and soothing
Muhammad Ali Khan et al., 2016, The Pakistan Journal of Agricultural Sciences
+60%
more patients reported mild pain in the plant ward than the control ward
Surgical patients in plant-decorated wards were far more likely to experience only mild pain
Muhammad Ali Khan et al., 2016, The Pakistan Journal of Agricultural Sciences
2.6×
plant ward patients were far more likely to find their ward attractive and beautiful
The presence of indoor plants improved patients' perception of their ward's attractiveness
Muhammad Ali Khan et al., 2016, The Pakistan Journal of Agricultural Sciences
+39%
more patients reported only mild fatigue in the plant ward than the control ward
Patients surrounded by indoor plants were somewhat more likely to report only mild fatigue during recovery
Muhammad Ali Khan et al., 2016, The Pakistan Journal of Agricultural Sciences
-24%
fewer patients suffered severe pain in the plant ward than in the control ward
Severe post-operative pain was less common among patients on a hospital ward furnished with indoor plants than in a matched ward without plants, in a single small study
Muhammad Ali Khan et al., 2016, The Pakistan Journal of Agricultural Sciences
12%
faster task completion with indoor plants present
Adding plants to a windowless computer lab made participants 12% quicker on a timed computer task
Virginia I. Lohr et al., 1996, Journal of Environmental Horticulture
+0.5
greater self-reported attentiveness with indoor plants present
Participants in the room with plants reported feeling 0.5 points more attentive (on a 1–5 scale) after completing the task
Virginia I. Lohr et al., 1996, Journal of Environmental Horticulture
−1.17 pts
combined biophilic environment produced the greatest reduction in anxiety scores
Combined biophilic environment produced the greatest anxiety reduction on the STAI
Su Xiaoxue et al., 2024, Frontiers in public health
−4.32 mmHg
combined biophilic environment cut diastolic blood pressure more than any other condition
Combined green wall + outdoor view environment produced the largest diastolic blood pressure reduction
Su Xiaoxue et al., 2024, Frontiers in public health
59%
green wall gave the highest chance of complete autonomic recovery among biophilic conditions
Green wall environment gave older adults the highest probability of complete autonomic (LF/HF) recovery
Su Xiaoxue et al., 2024, Frontiers in public health
3.60 vs 4.95 min
combined biophilic environment restored heart rate more than a minute faster than the control
Heart rate recovered faster in the combined biophilic environment than in the non-biophilic control
Su Xiaoxue et al., 2024, Frontiers in public health
8.8 / 10
combined environment produced the strongest felt connection to nature among all conditions
Older adults felt the strongest connection to nature in the combined green wall + outdoor view environment
Su Xiaoxue et al., 2024, Frontiers in public health
6.74 / 7
outdoor view environment produced the highest self-reported relaxation of all conditions
Outdoor view environment produced the highest self-reported relaxation among all conditions
Su Xiaoxue et al., 2024, Frontiers in public health
−5.22 mmHg
outdoor view environment produced the largest drop in systolic blood pressure
Outdoor view environment produced the largest systolic blood pressure reduction
Su Xiaoxue et al., 2024, Frontiers in public health
9%
combined biophilic environment showed the fastest early-phase heart rate variability recovery
The combined biophilic environment showed the fastest early-phase RMSSD (HRV) recovery
Su Xiaoxue et al., 2024, Frontiers in public health
84%
most studies found some degree of stress reduction from small-scale greenery
84% of included studies reported some degree of stress reduction from small-scale greenery
Jiaqi Gu et al., 2022, International Journal of Environmental Research and Public Health