A non-destructive delivery system is essential for foliar application of nutrients. Today, many spraying adjuvants are available. However, although most of these adjuvants are not harmful to plant foliage, their effect on leaf adsorption of nutrients under orchard conditions is very small. There is a group of silicon-based adjuvants which are said to be more efficient and are recommended for use in treating acute leaf shortage of nutrients, such as iron deficiency. These seem indeed to work better than most other spraying adjuvants, but as they were originally developed to improve herbicide sprays, they cause severe necrotic damage to the treated leaves. In order to obviate leaf damage while increasing nutrient uptake, we have developed a new non-destructive adjuvant product named Ferti-Vant. The composition of this system was specifically engineered to deliver nutrients through the plant "skin", the cuticular membrane, under field conditions. The present study included a scanning electron microscope (SEM) characterization of the effect of Ferti-Vant on the leaf surface activity of nutrients as compared to that of other common spraying adjuvants, including silicon-based adjuvants. Radioisotope assays and mineral analyses clearly indicate that Ferti-Vant is more effective in promoting lasting penetration of nutritional elements into citrus and olive leaf under field conditions as compared to other common spraying adjuvants.