Plants and Mental Health
Do houseplants and gardening help with stress and mood? Four published studies - a hospital window, a repotting experiment, a gardening meta-analysis and a 2022 review of indoor plants - and what they do and do not show.
“Plants are good for you” is repeated so often that it deserves checking. The short answer: there is real published evidence that contact with plants and gardening goes with lower stress and better wellbeing, and it is stronger than the evidence for plants “purifying” the air. It is also modest, often from small studies, and no substitute for treatment. Below are four studies you can read for yourself, and what each one actually found.
Two Ideas Behind the Research
Biophilia. The biologist E. O. Wilson proposed in 1984 that people have an inborn tendency to seek connection with nature and other living things. It is a hypothesis - a way of explaining why a green view feels restful - not a measured effect.
Attention restoration. Psychologists Rachel and Stephen Kaplan proposed that natural scenes hold our attention without effort and so give the capacity for deliberate concentration a rest. Again, a theory that guides the experiments, not a proven mechanism.
What Four Studies Found
1. A window with a view
The best-known study in this field looked at hospital records. Of patients recovering from gallbladder surgery in a Pennsylvania hospital, 23 whose rooms looked out on trees had shorter stays after surgery, fewer negative comments in the nurses’ notes, and took fewer strong painkillers than 23 matched patients whose windows faced a brick wall. It was published in Science in 1984. It was small, and it was about a view, not a pot plant - but it started the field.
2. Repotting versus a computer task
In a randomized crossover study, 24 young men each spent time transplanting an indoor plant and time on a computer task. After the transplanting they reported feeling more comfortable and soothed, a measure of sympathetic nervous activity fell where it had risen during the computer work, and diastolic blood pressure was lower. One short session, two dozen young men: a real result, and a narrow one.
3. Gardening, pooled
A meta-analysis that pooled 22 studies of gardening, including horticultural therapy, found a significant positive effect on health outcomes overall. The outcomes reported in those studies included reductions in depression and anxiety and increases in life satisfaction and quality of life. The authors note that there were signs of publication bias - studies with positive results being more likely to appear in print - and that the effect remained after adjusting for it.
4. Indoor plants, reviewed
A 2022 systematic review of 42 studies of indoor plants concluded that plants indoors affect people positively, particularly in relaxed physiology and cognition. When the authors pooled the numbers, the results that reached statistical significance were a small reduction in diastolic blood pressure and better academic achievement; effects on attention and response time pointed the same way but were not significant. They add that each of those pooled results rested on only two or three studies.
What This Adds Up To
- Gardening has the broadest support, which is not surprising: it combines being outdoors, moving about, daylight, routine and something to show for the effort.
- Indoor plants have support for a calming effect, from small and short studies.
- A view of greenery has one famous study and many that followed it.
The Caveats
- Many of the studies are small and short. A measurement taken minutes after an activity does not tell you about months.
- Publication bias is real in this field, as the gardening meta-analysis itself reports.
- An association is not a cure. People who garden may differ from people who do not in ways that also affect health.
- None of this research tested plants as a treatment for mental illness.
Making the Most of Plants
Nothing here needs a study to justify it:
- Put plants where you spend time - by your desk, in the room you use most, in your line of sight.
- Choose easy plants. A dying plant is not restful. Start with something forgiving such as a snake plant, a pothos or a ZZ plant.
- Let the care be unhurried. A few quiet minutes of watering and tidying is part of the point.
- Arrange a green view - a windowsill plant, or a desk that faces the garden.
- Garden if you can - a few containers count.
Frequently Asked Questions
Do houseplants really improve mental health?
There is published evidence that contact with indoor plants goes with a more relaxed state, mostly from small, short studies. That is a reason to enjoy them, not a treatment.
How do plants reduce stress?
Nobody has shown the mechanism. The usual explanations are the biophilia hypothesis and attention restoration theory, both described above.
Is gardening good for mental health?
A meta-analysis that pooled 22 studies reported a significant positive effect of gardening on health outcomes, including measures of depression and anxiety.
Can plants replace therapy or medication?
No. If you are struggling, please reach out to a doctor or another professional. Plants can sit alongside proper help.
How many plants do I need?
No study gives a number. One plant you see every day is a reasonable place to start.
Recommended Gear on Amazon
- Assorted live houseplant bundle - browse current options and reviews on Amazon.
- Desk planter with drainage - browse current options and reviews on Amazon.
- Long-spout watering can - browse current options and reviews on Amazon.
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