Radiation hormesis was studied for salad rocket plant (Eruca vesicaria sp.sativa), using different energies of X-ray (100 kV and 10 MV) . To get the optimum dose for plant to provide the highest growth, the dose for the seeds was changed from 0 to 3 000 mGy using 100 kV of X-ray. The highest growth of the plant was found for the dose of 600 mGy. When the seeds were irradiated to 600 mGy with 100 kV and 10 MV X-rays, in both cases, the growth of the irradiated seeds was higher than those without irradiation, where P-values were 0.0112 and 0.0214, respectively. In the case of 600 mGy irradiation, there was not any significant change in the plant growth between the seeds irradiated with 10 MV and 100 kV X-ray (P=0.862) .