Urban gardening spans home, community, institutional and commercial growing systems. The figures below show how widely results vary by site, crop, management, accounting method and geography, using measured studies from Sydney, Chicago, a five-country sample and U.S. commercial case studies.
Key Urban Gardening Statistics
The most broadly useful figures include:
- 13 small-scale organic urban farms and gardens were observed in Sydney, Australia, during a one-year study period.
- Sydney sites recorded 62 varieties of vegetables, fruit and herbs during the one-year study period.
- The mean Sydney urban-garden output was 5.94 kg/m² during the one-year study period.
- Sydney plot yields ranged from 1.99 to 15.53 kg/m² during the one-year study period.
- Sydney gardeners invested an average of 6.0 labor hours per square meter during the one-year study period.
- The five-country urban-agriculture sample recorded yields from 0.2 to 6.6 kg/m² during its case-study period.
- Mean yield in the five-country sample was 1.9 kg/m² during its case-study period.
- Mean calorie production in the five-country sample was 596 calories/m² during its case-study period.
- Mean irrigation water use was 122 L/m² in the five-country urban-agriculture sample.
- Water use per kilogram of food ranged from 6.9 to 646 L/kg in the five-country sample.
- At 40% of five-country sites, no electricity or fuel was used on-site during the case-study period.
- Mean soil organic matter was 13.3% in Chicago community gardens and 17.9% in Chicago urban farms in the sampling study.
- Mean total lead was 141.2 mg/kg in Chicago home gardens in the sampling study.
- Mean tomato yield ranged from 3.6 kg/m² in Chicago community gardens to 7.1 kg/m² in institutional gardens.
- Sydney’s mean benefit-to-cost ratio was 0.62 when labor and materials were included during the one-year study period.
- Seven of 14 USDA commercial urban-farm case studies earned revenue from off-site services during the case-study period.
- The five-country study recorded 128 different crops during its case-study period.
Contents
- Urban gardening participation, motivations and scope
- Urban garden yields and food production data
- Urban gardening water, energy and material inputs
- Urban garden soil fertility and contamination measurements
- Urban gardening economics and resource efficiency
- Urban gardening crop diversity and commercial activity
Urban Gardening Participation, Motivations and Scope
Urban gardening statistics do not describe one interchangeable population. The evidence here includes household plots, community gardens, institutional gardens, small organic farms and commercial urban farms, so each result needs its original definition.
The Sydney research followed 13 small-scale organic urban farms and gardens over one year. The sites produced 62 varieties of vegetables, fruit and herbs, while participating gardeners reported a mean gardening experience of 20.96 years and a median of 20 years; that experience measure was self-reported by study participants.
The Sydney survey asked about nine motivations on a 1–5 scale. Reducing personal food spending received the lowest mean motivation rating, although the opened source reports the ranking rather than a numerical mean.
The USDA commercial urban-agriculture study selected 14 U.S. farms as purposive case studies. Each had to earn at least $10,000 from agricultural-product sales, and all 14 participated in community or education events; these are case-study findings, not national participation rates.
Urban Garden Yields and Food Production Data
Yield measurements vary sharply across systems and crops. The Sydney sites averaged 5.94 kg/m², but observed plot yields ranged from 1.99 to 15.53 kg/m² during the one-year study period.
| Measure | Result | Population and period |
|---|---|---|
| Mean crop output | 5.94 kg/m² | 13 Sydney sites, one year |
| Plot-yield range | 1.99–15.53 kg/m² | Sydney sites, one year |
| Mean output per labor hour | 1.29 kg/h | Sydney sites, one year |
| Output per labor-hour range | 0.21–2.28 kg/h | Sydney sites, one year |
| Labor invested | 6.0 hours/m² | Sydney sites, one year |
Source: Small-scale urban agriculture results in high yields but requires judicious management of inputs to achieve sustainability. The labor definition is specific to that study.
A separate five-country study found a lower mean across heterogeneous farms and gardens: 1.9 kg/m², with a standard deviation of 1.4 kg/m² and a median of 1.5 kg/m². Its observed yield range was 0.2–6.6 kg/m², and mean calorie production was 596 calories/m² with a standard deviation of 477; the median was 439 calories/m².
The five-country results are a case-study distribution rather than a global average. Calorie conversion also depends on the crop mix, so calorie output should not be treated as interchangeable with mass yield.
Source: Food production and resource use of urban farms and gardens: a five-country study.
Urban Gardening Water, Energy and Material Inputs
Resource-use data show why management matters. In the five-country study, irrigation use between the first and third quartiles was 28.4–114 L/m², while the mean was 122 L/m²; the full observed range was 1.7–1,313 L/m² after excluding a separate 2,802 L/m² French-farm leak outlier.
Water use per kilogram of food ranged from 6.9 to 646 L/kg, with a mean of 71.6 L/kg. The wide range reflects different crops, site conditions and irrigation practices rather than a single typical urban-garden requirement.
Irrigation method was observed rather than randomly assigned, so the following values are comparisons within the sample:
- Drip-irrigated sites used 345±289 L/m² on average.
- Hose-irrigated sites used 104±201 L/m² on average.
- Watering-can sites used 74±63 L/m² on average.
Among 38 sites using compost, average application was 9.7±11.5 L/m² and the median was 4.9 L/m². At 40% of the five-country sites, no electricity or fuel was used on-site; sites using external energy averaged 1.7±3.9 kWh/kg of food, with a median of 0.5 kWh/kg among energy-using sites.
For context, only 21% of U.S. vegetable farms used irrigation in 2017, but that rural comparison is not an urban-gardening measure and should not be read as a benchmark for city sites.
Source: Food production and resource use of urban farms and gardens: a five-country study.
Urban Garden Soil Fertility and Contamination Measurements
Chicago measurements demonstrate the difference between soil fertility indicators and contaminant concentrations. In the sampling study, mean soil pH was 7.7 in both community gardens and urban farms, while mean organic matter differed by site class.
| Chicago site class | Organic matter | Total lead |
|---|---|---|
| Community gardens | 13.3% | 66.5 mg/kg |
| Urban farms | 17.9% | 42.2 mg/kg |
| Home gardens | 6.6% | 141.2 mg/kg |
| Institutional gardens | 5.3% | 89.54 mg/kg |
The same study reported mean available phosphorus from 94.3 to 225.4 mg/kg across the four site classes, and mean exchangeable potassium from 344.9 to 936.0 mg/kg. These are test-specific measures: available phosphorus is not total phosphorus, and exchangeable potassium is not total potassium.
Mean arsenic ranged from 5.0 to 7.4 mg/kg, while mean zinc ranged from 32.7 to 52.8 mg/kg across the four Chicago site classes. The lead, arsenic and zinc values are sampled-site means, not citywide estimates or universal safety thresholds.
Tomato yields in Chicago ranged from 3.6 kg/m² in community gardens to 7.1 kg/m² in institutional gardens. The soil study does not establish that the differences in tomato yield were caused by any single soil measurement.
Source: Chemical and biological indicators of soil health in Chicago urban gardens and farms.
Urban Gardening Economics and Resource Efficiency
Economic results depend heavily on whether unpaid or volunteer labor is assigned a monetary value. In Sydney, mean financial input value per kilogram of produce was $28.53 in 2020-era U.S. dollars as reported by the study, and that value exceeded local-store purchase cost for 53 of 62 varieties.
When labor and materials were included, Sydney gardens had a mean benefit-to-cost ratio of 0.62. When only material costs were included, the ratio rose to 2.81; this is a derived scenario that excludes labor and is not directly comparable with the full-cost result.
The same Sydney analysis reported mean emergy expended per joule of edible produce of 3.16×10^7 solar emjoules per joule. Nonrenewable materials represented 60.28% of input emergy, labor represented 29.34%, and renewable materials represented 10.28%; emergy categories follow the study’s accounting framework.
The mean environmental loading ratio was 5.82. A hypothetical maximum-substitution scenario raised renewable materials to 38.65% of inputs, raised the total renewable fraction to 43.03% and reduced the environmental loading ratio to 1.32; these are counterfactual results, not observed practice.
Commercial urban farms can also rely on services beyond crop sales. In the USDA case studies, seven of 14 farms earned revenue from off-site services such as landscaping, garden installation or custom hire; for five farms, those services supplied 8%–28% of total annual revenue.
Four USDA farms earned revenue from educational activities, typically 3%–14% of total earned revenue. Six earned income from on-site events, tours or land rent, and for two of those farms the activity represented at least 25% of earned revenue.
Source: The Promise of Urban Agriculture: National Study of Commercial Farming in Urban Areas (Summary). The USDA figures come from purposive commercial case studies, not a national prevalence estimate.
Urban Gardening Crop Diversity and Commercial Activity
The five-country study recorded 128 different crops across its farms and gardens. The number per site ranged from 1 to 83, with a mean of 20±16 crops and a median of 16.
Twenty-three crops, or 18% of all crops recorded, appeared at only one site. That uniqueness is measured within the study dataset and does not represent the full diversity of urban gardening worldwide.
The study also placed its results alongside ranges from cited literature. Professional or highly trained urban growers produced 5.4–7.1 kg/m² in the reviewed literature, while most urban plots produced 0.5–2 kg/m²; isolated community-garden and rooftop cases reached 3–6 kg/m², and exceptional individual gardens and rooftop farms reached 10–16 kg/m².
These literature ranges are not a pooled estimate. They show how reported production can differ between ordinary plots, highly managed operations and exceptional sites, while the five-country study provides a separate case-study distribution.
Source: Food production and resource use of urban farms and gardens: a five-country study.