How Much Food Can We Grow in Urban Areas? Food Production and Crop Yields of Urban Agriculture: A Meta‐Analysis

Abstract

Urban agriculture can contribute to food security, food system resilience and sustainability at the city level. While studies have examined urban agricultural productivity, we lack systemic knowledge of how agricultural productivity of urban systems compares to conventional agriculture and how productivity varies for different urban spaces (e.g., allotments vs. rooftops vs. indoor farming) and growing systems (e.g., hydroponics vs. soil‐based agriculture). Here, we present a global meta‐analysis that seeks to quantify crop yields of urban agriculture for a broad range of crops and explore differences in yields for distinct urban spaces and growing systems. We found 200 studies reporting urban crop yields, from which 2,062 observations were extracted. Lettuces and chicories were the most studied urban grown crops. We observed high agronomic suitability of urban areas, with urban agricultural yields on par with or greater than global average conventional agricultural yields. “Cucumbers and gherkins” was the category of crops for which differences in yields between urban and conventional agriculture were the greatest (17 kg m−2 cycle−1 vs. 3.8 kg m−2 cycle−1). Some urban spaces and growing systems also had a significant effect on specific crop yields (e.g., tomato yields in hydroponic systems were significantly greater than tomato yields in soil‐based systems). This analysis provides a more robust, globally relevant evidence base on the productivity of urban agriculture that can be used in future research and practice relating to urban agriculture, especially in scaling‐up studies aiming to estimate the self‐sufficiency of cities and towns and their potential to meet local food demand.

Opportunities and challenges for strawberry cultivation in urban food production systems

“…Yields for strawberries grown in UH can vary between 0.87 kg/m 2 / year for soil-based open-air cultivation (Passos et al, 2015) to 11.49 kg/m 2 /year for four stacked horizontal layers growing systems with artificial lighting (Hofkens et al, 2021). Based on 70 observations in the meta-analysis of Payen et al (2022), the average strawberry yield of UH is 2.5 kg/m 2 /year, which is similar to that expected from conventional horticulture of 2.2 kg/m 2 /year. Producing strawberries in UH could reduce the volume of imported strawberries during winter months and bring local/national strawberry production closer to all-year-round production, reducing foodmiles associated with imports.…”

“…The impact of UH on the three pillars of sustainability—environment, society and economy—has been discussed by many authors (de Oliveira et al, 2020; Dorr et al, 2021; Edmondson et al, 2020; Eigenbrod & Gruda, 2015; Evans et al, 2022; Gómez et al, 2019; Kalantari et al, 2018; Khan et al, 2020; Morgan, 2014; Payen et al, 2022; Specht et al, 2015), with some variation between the spectrum of open‐air, low‐tech to indoor, high‐tech urban farms, as illustrated in Figure 1.…”

“…UH is defined as the production of food in urban and peri‐urban areas, either using soil‐based horticulture (SBH) in green infrastructures such as allotments, domestic gardens and raised beds, or in CEA using grey infrastructure, which is within or on top of buildings such as rooftops, warehouses or offices (Edmondson et al, 2020; Stormonth‐Darling et al, 2020). UH is estimated to contribute to 15%–20% of global food production, and could reach 30% or even more of local food production if all the available food producing areas were to be utilised (Abdulkadir et al, 2012; Grafius et al, 2020; Payen et al, 2022).…”

Promoting Urban Farming for Creating Sustainable Cities in Nepal

“…Additionally, algae can be used as mulch to retain soil moisture, which helps improve crop production. For example, it has been reported that potato yield with algae mulching was 10 times more than from the traditional farming methods in open areas [36].…”

Development of the crop coefficient for vertically trained cucumber vines grown in soilless media under naturally ventilated greenhouse conditions

“…Zero-energy naturally ventilated greenhouses offer higher benefits at low cost as they do not require additional heating or cooling. Greenhouses provide higher water and nutrient efficiency and can yield two to five times higher yields than outdoor horticulture production (Payen et al, 2022). Currently, 70,000 ha of the area in India is under protected cultivation.…”