This work presents a new process, based on the green nanoparticles Fe 3 O 4 and magnetization coupling for the treatment of saline well water. In this context, iron nanoparticles were synthesized using Eucalyptus globulus leaves. The nanomaterials were characterized by scanning electron microscopy and infrared for identification. Batch experiments were conducted to illustrate the optimal parameters related to contact times and the mass of nanoparticles. The latter marked an optimal contact time of 100 min and a mass of 56 mg/L accompanied by a magnetic treatment for a contact time of 48 min. The results showed a significant (R 2 = 0.93) water salinity reduction (67%) and a potential for improvement in the germination of tomato seeds (81%) through the investigation of the evolution of the length of the roots, the stems, and the number of germinated seeds.