Effect of Light on the Yield and Nutrient Composition of Selected Mint Species Grown in a Controlled Environment

The experiment was conducted in a greenhouse and a growth chamber, in a randomized block design, with three replicates. The use of light-emitting diodes (LEDs) with varying wavelengths, combined with adequate nutrition, positively influence yield and the content of essential macronutrients and micronutrients in mint plants, which play a key role in the processes of growth and development. The average total yield of mint ranged from 23.1 g plant−1 to 48.1 g plant−1, while marketable yield ranged from 22.5 g plant−1 to 47.6 g plant−1. Exposure to violet LED light led to the highest increase in yield. The content of all analyzed macronutrients increased in plants of the evaluated mint species exposed to LED light. On average, the content of N, P, K in the aerial parts of mint plants increased significantly by around 25%, 56%, and 42%, respectively, under exposure to violet LED light, and by around 19%, 44%, and 37%, respectively, under exposure to yellow LED light. The values of K:Ca, K:Mg, and K:(Ca + Mg) ratios were higher in plants grown under LED light than in plants exposed to sodium light, whereas the opposite was noted for the Ca:P ratio. Exposure to violet or yellow LED light did not induce significant changes in Mn, Zn, Cu, and Fe uptake by mint plants. The micronutrient content of plants was largely determined by mint species. Mentha piperita plants had the highest Zn content, and Mentha suaveolens plants had the highest concentrations of Mn, Cu, and Fe.