Experiments to determine the efficacy of different nano-particle systems to deliver nutrients to citrus leaves were started by optimizing conditions for experimental treatments. In general, the experimental design consists of delivering of Mg to citrus leaves by means of three different nano-particle systems. Given their chemical and physical properties, we have selected PAMAM-dendrimers (~ 5 nm), kaolin particles (~1-5 um) and liposomes (~70 nm). To maximize efficiency, conditions of Mg deficiency were created by irrigating trees with a nutrient solution without Mg. Trees developed Mg deficiency symptoms within a few months and are now ready for experimental use (Phase 1). In phase 2, kinetic studies on the binding or carrying capacity of the different nano-particles to Mg were conducted. Concentration dependent kinetic experiments indicated that each PAMAM-dendrimer nano-particle is capable of binding a specific amount of Mg ions. Binding of Mg was demonstrated to be reversible depending on the pH of the environment. Concurrently, kaolin particles were treated similarly and showed a stronger Mg binding capacity than PAMAM-dendrimers. Chemical analysis showed that, although kaolin particles already contain Mg, they have sufficient exchangeable binding sites to bind additional cations. Liposomes, by their hydrophobic nature, will trap solutions of any concentration as they form spherical vesicles from lipid sheets. Greenhouse treatments have commenced with PAMAM dendrimers and the corresponding control of aqueous Mg solution at similar concentration. Treatments with other nano-particles will follow.