Nutrient Content of Cabbage and Lettuce Microgreens Grown on Vermicompost and Hydroponic Growing Pads

Abstract

Current food systems, the collective processes involved in food production, distribution and consumption, create a dichotomous problem of nutritional excess and insufficiency and are not environmentally sustainable. One specific nutritional problem that needs attention is mineral (e.g., Fe, Zn) malnutrition, which impacts over two-thirds of the World’s people living in countries of every economic status. Microgreens, the edible cotelydons of many vegetables, flowers, and herbs, is a newly emerging crop that is potentially a dense source of minerals that can be sustainably produced in almost any locale. In this study, the nutrient contents of lettuce and cabbage microgreens grown hydroponically (HP) and on vermicompost (C) were assessed and compared to each other as well as to the nutrient contents of store-bought cabbage and lettuce (mature vegetables). Of the 10 nutrients examined (P, K, S, Ca, Mg, Mn, Cu, Zn, Fe, Na), C cabbage microgreens had significantly larger quantities of all nutrients than HP cabbage microgreens (p-values <0.00321) with the exception of P; C lettuce microgreens had significantly larger quantities of all nutrients than HP lettuce microgreens (p-values <0.024) except for P, Mg and Cu. Compared to the mature vegetable, C or HP cabbage microgreens had significantly larger quantities of all nutrients examined (p-values <0.001) and C or HP lettuce microgreens had significantly larger quantities of all nutrients except for Ca and Na (p-values <0.0012). Results of this study indicate that microgreens grown on vermicompost have greater nutrient contents than those grown hydroponically. As microgreens can be grown easily in one’s home using the methods used in this study, they may provide a means for consumer access to larger quantities of nutrients per gram plant biomass relative to store-bought mature vegetables, which had lower nutrient contents than microgreens with respect to most nutrients examined.