Summary: New research shows that community gardening lowers stress and anxiety, boosts fiber intake and physical activity, and can help reduce risks for cancer and other chronic diseases.
Source: University of Colorado
Get more exercise. Eat more plants. Connect with neighbors.
As people plan health-focused goals for the coming year, new research from CU Boulder suggests adding community gardening to the list. The study found measurable improvements in diet, activity and mental well-being among adults who began gardening.
Funded by the American Cancer Society, this is the first randomized, controlled trial to evaluate the effects of community gardening on adults’ diet, physical activity and anthropometry. Participants who received garden plots increased their daily fiber intake and weekly physical activity—both established factors in reducing cancer and chronic disease risk—and reported lower levels of stress and anxiety.
The findings were published Jan. 4 in the journal Lancet Planetary Health.
“These results provide concrete evidence that community gardening can play an important role in preventing cancer, chronic diseases and mental health disorders,” said senior author Jill Litt, a professor in the Department of Environmental Studies at CU Boulder.
Addressing a research gap
Litt has focused her career on identifying affordable, scalable and sustainable interventions to lower disease risk, especially for low-income communities. Community gardening was an appealing option because of its accessibility and the common belief that gardening improves well-being.
Despite widespread anecdotal reports, rigorous evidence of gardening’s effects has been limited. Observational studies had linked gardening with healthier diets and weight, but those studies could not determine whether healthier people choose to garden or whether gardening itself produces health benefits. Prior to this trial, only three randomized controlled trials had examined gardening, and none studied community gardens specifically.
To address that gap, Litt and colleagues recruited 291 adults from Denver-area waiting lists for community garden plots. Participants had not gardened in the previous two years, averaged 41 years of age, included a substantial proportion of Hispanic participants, and had a high share of low-income households. After the final spring frost, half were randomly assigned to receive a community garden plot, seeds, seedlings and a beginner course through Denver Urban Gardens; the other half remained on a waiting list and served as the control group for one year.
Both groups completed periodic dietary recalls, wore activity monitors for a week at several time points, filled out surveys about mental health, and had body measurements taken. Researchers analyzed outcomes using intention-to-treat methods and observer-blinded procedures.
More fiber, more movement
By autumn, participants assigned to the gardening group consumed, on average, 1.4 grams more fiber per day than the control group—about a 7% increase. Though modest, that rise is meaningful because dietary fiber strongly influences inflammation, immune responses, gut microbiota and metabolic health, all of which relate to diabetes and certain cancers. Average adult fiber intake in the U.S. remains well below recommendations, so even small increases can benefit public health.
Gardening participants also increased moderate-to-vigorous physical activity by about 42 minutes per week compared with controls. Public health guidelines recommend at least 150 minutes of activity per week; just two to three visits to a community garden each week accounted for roughly 28% of this target for many participants.
Importantly, gardeners reported lower perceived stress and anxiety. Those who began the study with the highest stress and anxiety experienced the largest improvements, showing that gardening can benefit mental health across a diverse participant pool.
The trial demonstrated that even novice gardeners can achieve tangible health improvements in their first season, and the investigators expect benefits may grow as gardeners gain experience and larger harvests.
Social benefits and access
Linda Appel Lipsius, executive director of Denver Urban Gardens, said the results echo the nonprofit’s long-standing experience: community gardens can be transformative. Many participants live in neighborhoods with limited access to affordable fresh produce. For low-income immigrants and renters, garden plots provide space to grow culturally important crops and preserve culinary traditions.
Beyond food production, community gardens foster connection. Litt noted that while solitary gardening offers benefits, gardening alongside others adds social interaction and shared learning. Neighbors trade techniques and recipes, building relationships that extend beyond the garden beds.
Litt hopes these findings will encourage health professionals, policymakers and urban planners to consider community gardens and other nature-based gathering places as integral elements of public health infrastructure.
Researchers from the Colorado School of Public Health, Colorado State University and Michigan State University also contributed to the study.
About this mental health and cancer research news
Author: Lisa Marshall
Source: University of Colorado
Contact: Lisa Marshall – University of Colorado
Image: The image is in the public domain
Original Research: Open access. “Effects of a community gardening intervention on diet, physical activity, and anthropometry outcomes in the USA (CAPS): an observer-blind, randomised controlled trial” by Jill Litt et al. Lancet Planetary Health
Abstract
Effects of a community gardening intervention on diet, physical activity, and anthropometry outcomes in the USA (CAPS): an observer-blind, randomised controlled trial
Background
Unhealthy diet, physical inactivity and social isolation are modifiable risk factors for many chronic diseases. Nature-based community interventions, such as shared garden spaces, may reduce these risks. This trial tested whether a community gardening intervention improves diet, activity levels and anthropometric outcomes in a diverse adult population across age, ethnicity and socioeconomic status.
Methods
In this observer-blind, randomized, controlled trial, adults on Denver Urban Gardens waiting lists in Denver and Aurora (CO, USA) who had not gardened in the previous two years were recruited. Participants were randomly assigned to receive a community garden plot and gardening support (intervention) or to remain on the waiting list and not garden for one year (control). Researchers were masked to group allocation. Primary outcomes included dietary intake, physical activity measured by accelerometry, and anthropometry; secondary outcomes included perceived stress and anxiety. Data collection included three dietary recalls, seven-day accelerometry, surveys and body measurements at three time points: baseline (spring), autumn, and post-intervention winter. Analyses followed intention-to-treat principles and used mixed models to test intervention effects. Data collected after Feb 1, 2020, were excluded to avoid potential pandemic-related confounding.
Findings
From Jan 1, 2017, to June 15, 2019, 493 adults were screened and 291 completed baseline measures and were randomized (intervention n=145; control n=146). Mean age was 41.5 years; most participants were female; 34% identified as Hispanic. Most measurements (81%) occurred before the COVID-19 pandemic. One intervention participant experienced a minor allergic event in the garden. Significant intervention effects were found for fiber intake and moderate-to-vigorous physical activity. The intervention group increased fiber intake by an average of 1.41 g/day at the autumn timepoint and increased moderate-to-vigorous physical activity by approximately 5.8 minutes per day relative to controls. No significant differences were observed for combined fruit and vegetable intake, Healthy Eating Index scores, sedentary time, body mass index or waist circumference. Difference-score analyses showed larger reductions in perceived stress and anxiety in the intervention group compared with controls.
Interpretation
Community gardening offers an accessible, nature-based approach to improve well-being and address behavioral risk factors for non-communicable and chronic diseases across diverse adult populations, including new gardeners.
Funding
American Cancer Society; University of Colorado Cancer Center; University of Colorado Boulder; National Institutes of Health; U.S. Department of Agriculture National Institute of Food and Agriculture; Michigan AgBioResearch Hatch projects.