Production of microgreens under a vertical hydroponic system for nutritional and environmental security

Urban farming systems play a pivotal role in providing fresh, nutritious vegetables to consumers. Microgreens specifically can fit this need. The present study was carried out in the Department of Horticulture, Central University of Tamil Nadu, Thiruvarur, during the period 2023 to 24. To analyse the suitability of microgreens for urban farming, four different microgreens, namely purple radish (Raphanus sativus), fenugreek (Trigonella foenum-graecum), red amaranth (Amaranthus tricolor) and coriander (Coriandrum sativum) were grown under a vertical ‘A’ frame hydroponic system using palmyra fibre waste as root supporting material. The experiment was laid out in a factorial completely randomised block design (FCRD) with different types of containers as a one factor and different nutrient solutions as another factor. Growth parameters (Germination %, length of seedling, yield) and biochemical parameters (carbohydrate, protein, vitamin C, total chlorophyll, carotenoids, total phenol, flavonoids, antioxidants) were documented in all four microgreens. Elemental profiling (29 mineral nutrients) of microgreens samples was done. The results of the experiment indicated that ‘protray on plastic tray’ as a container performed superiorly. Among the nutrient solutions, vermiwash and seaweed extract gave the best results. The interaction between the type of containers and nutrient solutions showed that the combination of protray on a plastic tray with vermiwash solution and seaweed extract performed best for microgreens species. Improved germination and yield of microgreens in plastic tray containers can be attributed to their superior moisture retention. Vermiwash and seaweed extract enhanced the yield and nutrient content of microgreens, as these are rich in micro, macro nutrients and plant growth-promoting hormones. The carbon sequestering ability of individual microgreens was also recorded. In conclusion, this study underscores the potential of vertical hydroponic systems for microgreens production, offering both nutritional and environmental benefits.