Valerian (Valeriana officinalis L.) is a medicinal plant that contains active compounds such as flavonoids and alkaloids that are important as antioxidants. The aim of this research was to determine the effect of humic acid concentration in different planting media on the antioxidant content. The main factor of this experiment was the concentration of humic acid added to the planting media at concentrations of 0, 4, 8, and 12 g kg-1. The second factor was the planting medium, of which there were three types: sand/soil (1 kg kg-1), husk/soil (1 kg kg-1), and zeolite/soil (0.5 kg kg-1). We determined the biomass, antioxidant content (polyphenols, flavonoids, and alkaloids), and IC50 values of valerian plants grown in various media. Our results show that the combination of the humic acid and planting medium affected the antioxidant content and activity in valerian plants. In particular, the planting medium containing zeolite and 8 g kg-1 of humic acid increased the antioxidant content and activity. From the result it can be concluded that a combination of humic acid and zeolite medium can be applied for valerian’s farmer.