The aim of the study was to evaluate the effect of various amounts of vermicompost (0, 10, 20, 25 and 50%) and Eisenia fetida earthworms (0, 10, 20 individuals per pot) on the weight of carrot roots and leaves and their vitamin C content on the 100th day after seeding. The achieved results indicate that along with the increasing content of vermicompost in the soil substrate the weight of roots and leaves was rising and the content of vitamin C was decreasing. The weight of roots was increasing more dynamically than the weight of leaves. The high proportion-even 50% of Vc-in the soil substrate did not have a negative impact on the formation of aboveground and underground phytomass. The earthworms had a positive influence on the formation of carrot roots and leaves. The impact on the roots was stronger. The impact of earthworms on the formation of phytomass depended on the interactive impact of the vermicompost quantity in the substrate and number of earthworms. The smallest percentage increase of roots and leaves yields with both numbers of earthworms was achieved if the earthworms were put into the substrate of the highest 50% proportion of vermicompost.