Evaluation of different growing substrates for microgreens production

Microgreen vegetables have been increasing on the fresh market and appreciated for their visual appearance and nutraceutical properties. The phytonutrient compositions can vary from species to species and from light intensity and photoperiod in the growing conditions. The aim of this work was to evaluate the effect of three different substrates on yield and quality of three leafy vegetables harvested at the microgreens stage. The leafy vegetables, green and red basil (Ocimum basilicum L.) and rocket (Eruca sativa Mill.) were grown hydroponically in a floating system with half-strength Hoagland. The substrates tested were coconut fiber, vermiculite, and jute. The experiments were carried out in micro experimental growing (MEG®) cabinet equipped with LED lighting system. The effect of substrates on the three vegetable species was evaluated by measuring the yield, leaf pigments (chlorophyll and carotenoids), and phenols as antioxidant compounds. Data showed that yield was affected by substrates in different species and ranged from 1655 to 2269 g/m-2. The highest value was found in rocket grown on jute substrate and the lowest in red basil grown in the same substrate. The chlorophyll concentration was higher in rocket grown in coconut fiber, while the lowest was observed in red basil grown on vermiculite. Total carotenoids instead did not change among species and substrates.