Biomass and Biometric Relationships of Ornamental Flower Seedlings Under Different Protected Environments and Substrate Compositions

Ornamental plants and flowers increasingly bring urban populations closer to nature in the pursuit of improved quality of life. This study aimed to evaluate the biomass accumulation of Chinese pink (Dianthus chinensis L.), English lavender (Lavandula angustifolia Miller), and wild pansy (Viola tricolor L.) seedlings grown under different protected environments and substrate compositions based on peat and vermiculite. The experiment followed a completely randomized design in a 4 × 5 factorial scheme (four protected environments × five substrate compositions). The environments included three screenhouses with black screens providing 18%, 30%, and 50% shading, and one greenhouse covered with plastic film and a 42–50% shading screen under the film. Within these environments, five substrate compositions were assessed. The cultivation environment and substrate can influence the growth of ornamental flower seedlings, as observed in this study for D. chinensis, L. angustifolia, and V. tricolor. For shoot dry mass, root dry mass, and total dry mass of all three ornamental species, the highest values were observed in the greenhouse with 42–50% shading under the plastic film. It was concluded, for these experimental conditions, that the greenhouse environment with 42–50% shading, combined with a substrate containing 80% Carolina Soil®, was the most suitable condition for developing D. chinensis seedlings. For L. angustifolia, optimal growth occurred with 100% Carolina Soil® under the same greenhouse conditions, whereas for V. tricolor, the best growth was achieved with substrates containing at least 80% Carolina Soil®.