Abstract: In this study, the zinc oxide prepared from three different precursors: zinc sulfate hepta hydrate, zinc nitrate hexahydrate and zinc acetate dihydrate, has been tested on the germination of Lepidium sativum seeds. Radicles growth of selected seeds responded differently to the treatment of various oxides synthesized. The results show a very significant inhibitory effect on the germination and the growth of rootlets observed in the case of ZnO synthesized from zinc sulfate heptahydrate, compared to the control and other oxides prepared from zinc nitrate or acetate zinc. We found that, after a week of incubation in the presence of ZnO synthesized from zinc sulfate, 65% inhibition of seed germination, the length of the radicles Lepidium sativum decreased almost 90 to 100% and the inhibitory action of this oxide is irreversible after cessation of treatment.