Vermicomposting is a method that allows for the environmentally friendly management of plant organic waste through the activity of concentrated earthworm populations. As a result of an appropriately conducted process, it is possible to obtain a valuable organic fertilizer, abundant in nutrients for plants as well as the development of a favorable (qualitatively and quantitatively) earthworm population structure. This paper presents the results of the vermicomposting process of waste plant mass with the use of vermireactors with different designs. In conventional no protective substrate (NPS) vermireactors, plant waste was the only habitat for earthworms, whilst protective substrate (PS) vermireactors also had a medium to shield the earthworm population in the event of the accidental introduction of toxic waste to these invertebrates. A positive effect of the PS vermireactor construction in the protection of an earthworm population against the potential use of stressful waste was found, as populations of Eisenia fetida were monitored and the development was noted during the vermicomposting with both methods. The largest differences between the populations (PS vs. NPS vermireactors) were demonstrated after 40 and 50 days and related to the number of immature animals (PS > NPS by 30.7%; p < 0.05) and cocoons (PS > NPS by 34.8%; p < 0.05). There were no significant differences between the PS and NPS in the biomass of immature E. fetida and cocoons. The vermicomposts obtained were not significantly different form each other but they were characterized by a higher content of C, N, P, K, Ca and Mg compared to the initial waste biomass. Contents of Cu, Mn, Zn, Cd and Pb in vermicomposts did not prevent their use as fertilizers.