A Review on Sustainable Microgreen Cultivation for Urban Farming with Minimal Resources

Microgreens, nutrient-rich and high-value crops, are becoming essential in urban agriculture because of their quick development cycles (7–21 days), low resource demands, and considerable nutritional and health advantages. Microgreens are abundant in vitamins (C, E, K), minerals (K, Ca, Fe, Zn, Mg), antioxidants (polyphenols, carotenoids, glucosinolates), and bioactive compounds, providing antioxidant, anti-inflammatory, anticancer, antidiabetic, antimicrobial and neuroprotective effects, thereby mitigating malnutrition and chronic disease risks. Their cultivation is resource-efficient, utilizing 158–236 times less water than mature crops, requiring minimum space and eliminating the need for pesticides, rendering them optimal for sustainable urban agriculture. Diverse cultivation techniques, such as cocopeat, soil-based systems, vermiculite/perlite, hydroponic/soilless approaches and alternative substrates (e.g., compost, coconut coir, rice straw), improve production, nutrient composition, and sustainability. Cocopeat facilitates accelerated development and enhances carotenoid and chlorophyll concentrations, whereas soil-based substrates with organic additions augment micronutrient availability. Hydroponic techniques, including aeroponics and nutrient film technology, diminish nitrate concentrations and increase yields, while local substrates such as sugarcane bagasse and composted waste improve cost-efficiency and environmental sustainability. Critical determinants affecting microgreen cultivation encompass light (blue/red LEDs, 12–24-hour photoperiods), temperature (24–28°C), humidity (45–65%), seed density and nutrient solutions (e.g., calcium fertigation, Hoagland’s solution). Optimized conditions improve biomass, bioactive chemicals, and shelf life. Microgreens, such as cabbage, amaranth, and basil, are versatile in various growing media and environmental conditions, rendering them a scalable and sustainable solution for urban food security and nutritional improvement with low ecological impact.