Effect of Different Substrates and Protected Environments on Growth, Chlorophyll, and Carotenoid Contents of Kale Microgreens and Baby Leaf

Abstract

Microgreens and baby leaves are increasingly appreciated and consumed due to the increased concentrations of antioxidant compounds, vitamins, nutrients, and minerals than adult plants. The objective was to evaluate the effect of different substrates and protected environments on the growth of microgreen and baby leaf kale (Brassica oleracea var. sabellica L.) and their contents of carotenoids and chlorophylls. The experiments were carried out in a completely randomized design in a factorial arrangement of 4 × 2 (four environments × two substrates) for the microgreens and 4 × 5 (four environments × five substrates) for the baby leaf, both with six replications. For microgreens, the Carolina Soil® commercial substrate promoted greater height, fresh matter, dry matter, productivity, chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids in all evaluated environments. In the greenhouse with a screen of 35% shading under the film, greater height, fresh matter, dry matter, and productivity were obtained, and in the greenhouse with a screen of 42/50% shading under the film, higher contents of microgreen chlorophylls and carotenoids were obtained. For baby leaves, the greenhouse with 42/50% shading screen under the film promoted plants with greater height, fresh matter, dry matter, and productivity in all substrates. The baby leaf grown in the greenhouse with a screen of 35% shading under the film showed higher chlorophyll and carotenoid contents in the pure Carolina Soil® substrate. For greater productivity, with higher contents of pigments, greenhouses with screens under the film and the use of organomineral commercial substrate are the most suitable for microgreen and baby leaf kale.