Stinging nettle (Urtica dioica L.) is a widespread wild perennial plant species important for its medicinal properties and nutritional properties. In addition to wild nettle collected from natural habitats, cultivated nettle with known and consistent chemical composition is increasingly in demand. In cultivation, the growth and development of stinging nettle and the availability of nutrients are influenced by biotic (plant age), abiotic (climate) and technological factors (fertilization). This nitrophilous species requires higher amounts of nitrogen for its cultivation. However, excessive nitrogen fertilization can result in reduced dry matter, iron, total phenols, and ascorbic acid content. Due to the increasing use of nettle, more research has recently been conducted on growing this species according to organic principles, including the use of organic fertilizers. The aim of the study was to investigate the effects of organic (1. 'Lumbrical'; 2. 'Siforga') and mineral fertilizers (3. NPK 7-20-30) at the rate of 100 kg N ha-1 compared to the control (4. unfertilized) on the growth, development and specialized metabolites of nettles planted in autumn (2020) and spring (2021). From the studies, it can be concluded that morphological characteristics as well as mineral composition, content of vitamin C and antioxidant capacity were higher influenced by fall planting, while phenolic compound content and nettle yield were higher influenced by spring planting. It can also be concluded that organic fertilization had a higher influence on several studied components (yield, mass of herbs per planting site, leaf width, and amount of N, Ca, and Mg) compared to mineral fertilization.