Common valerian provides a pharmacopoeial raw material (rhizome with roots) used in the treatment of nervous tension and sleep disorders. In accordance with the European Pharmacopoeia, the drug is standardized on the content of sesquiterpenic acids and essential oil (EO). Valerian belongs to the plants introduced into cultivation only in the second half of the twentieth century. Still, little is known on the factors affecting its development and accumulation of raw material biomass and biologically active compounds. Our research indicates a significant impact of light on the yield of valerian raw materials and their quality. Higher roots mass and the content of EO are observed in plants grown in full sunlight compared to those from shade. In turn, the content of sesquiterpenic acids is higher in plants grown in shade. Valerian’s underground organs consist of rhizome bearing numerous roots, differing in diameter. The major mass of these organs is formed by thick roots (compared with the rhizome and thin roots), characterized with the highest content of sesquiterpenic acids and EO. In Poland, one-year and one-and-a-half-year systems of valerian cultivation are used. The yield of raw material is about 35% higher in the latter one. Intensive root mass increment is observed especially in the autumn, thus, the later the harvest takes place the better. A significant problem in valerian production is bolting, which contributes to a distinct reduction in the yield, especially in one-and-a-half-year cultivation. Bolts can be used to obtain by-products such as flowers, applied (in the form of extracts) in organic farming to protect plants against some pests. The composition of the root and flower EO is diverse. Oxygenated monoterpenes and sesquiterpenes, with bornyl acetate as a major compound, dominate in the root EO, whereas in the flower EO fatty acids and sesquiterpenoids form fundamental parts, with the clear domination of hexadecanoic acid.