Urban gardens, including Family Allotment Gardens (FAGs) and community gardens (CGs), play an increasingly important role in the ecological and social structure of cities that are to be adapted to climate change. For this purpose, alongside recreational and productive benefits, regulatory ecosystem services are becoming increasingly important. The aim of this study, conducted in Warsaw, was to examine the relationship between five classified types of vegetation use in urban gardens—turf, flower, vegetable, orchard, and abandoned— in the terms of biodiversity and ecosystem services they provide. The study places particular emphasis on floristical biodiversity and regulating services (e.g., microclimate regulation, water retention, air quality improvement, and pollinator support), and introduces a novel consideration of abandoned plots with spontaneous vegetation, which have been marginally addressed in previous studies despite their growing presence in cities. Field data were collected from 44 garden plots. Results showed that while flower and orchard gardens provide the broadest range of regulating ecosystem services, abandoned plots exhibit the highest biodiversity and vegetation density, indicating their potential as future ecological hubs. However, their current contribution to ecosystem functioning remains limited due to their early successional stage. Overall, differences in ecosystem service provision between garden types were smaller than anticipated, suggesting the complexity of multiple factors influencing service quality. There was considerable within-group variation between the identified types, indicating that microscale management and vegetation structure may be more significant than formal garden classification. We argue that the observed, short-term and small-scale forms of greenery in urban gardens are insufficient to produce an impact at a supra-local scale.