Urban gardening is not a new phenomenon but it has received considerably more practical and academic interest in recent years. Studies on economic aspects such as crop yields, inputs and outputs of production, productivity, gross margins and the contribution to home economics are rare, especially in Europe. While urban gardening plays an important role in the Global South, its role in Western Europe for food productivity and home economics is currently under-researched. The aim of this study is to analyse European urban gardeners' economic performance and self-sufficiency on a household level, as well as to reach a better understanding of their contribution to food self-provision and food security in the metropolitan areas. In a study carried out in 2014 with on-site personal and with online questionnaires participated 180 urban gardeners from three case study cities (Ljubljana, Milan, and London). Results from the economic analysis showed that although for most urban gardeners, profit is not their main motivation, the economic calculation shows that productivity in small urban plots can be comparable to market garden production. Urban gardeners are saving money, especially when, compared to retail prices for regular produce or organic produce, their input is included in the gross margin calculation. We conclude that, in the case-study cities, the self-provisional potential of urban gardeners' households to adequately cover the annual vegetable need of five-a-day servings can be met under three conditions: (1) sufficient garden size; (2) increased area productivity, and (3) sufficient labour-hour inputs. Urban food cultivation is generally associated with markets and farmers' markets, limited land space, a fierce contention for land, as well as a reliance on urban organic solid waste or water for soil efficiency (van Veenhuizen, 2006). It can also potentially use various agricultural inputs such as mineral fertilisers, plant-protection products, water (waste and fresh) and soils. However, institutional regulations and designation in city spatial plans are advised in order to avoid the potential risks of contamination of produce and drinking water resources (Mougeot, 2000).