Growth and Yield of Kale, Swiss chard, Amaranth, and Arugula microgreens in response to different growing medium substrates

Microgreens are relatively novel food with high nutrition and dietary benefits that can be influenced by the growing medium. Two experiments were performed to develop an optimum media for microgreensfrom kale (Brassica oleracea L. var. acephala), Swiss chard (Betavulgaris var. cicla), arugula (Eruca vesicaria ssp. sativa), and amaranth (Amaranthus tricolour L.). Experiment 1 was screening of media T1 = 30% vermicast + 40% sawdust + 30% perlite; T2 = 30% vermicast + 50% sawdust + 20% perlite; T3 = 50% vermicast + 30% sawdust + 20% perlite; T4 = 30% vermicast + 40% sawdust + 30% mushroom compost; T5 = 30% vermicast + 20% sawdust + 20% perlite + 30% mushroom compost; and a negative control (NC) = 50% sawdust + 50% mushroom compost. The positive control was Promix BX™ potting mix alone. Experiment 2 was to test the efficacy of two different sources of mushroom compost (White oyster mushroom compost (MC1) and Shiitake mushroom compost (MC2)) added to media T1 to T5 above. The results showed that the media physicochemical properties varied across treatments. Higher chemical parameters were obtained for T4, T5, and media containing MC1. Porosity and water retention were increased in media containing MC2 compared to the other.Seed germination, plant height, and microgreen yield were statistically (P>0.05) enhanced by T2 and T4 that contained MC2 compared to the rest. Microgreens yield was approximately three times higher in T2 and 4 with added MC2, except the yield of arugula which was two times higher in these media compared to the control. Overall, T5 alone, and T2 and T4 with added MC2 were the most effective media for microgreen production. Future studies will assess microgreens’ nutrients in different media.