The acclimatization of micropropagated plants is a crucial stage to ensure their growth and adaptation under greenhouse and open field conditions. This study aimed to determine the fertilization requirements of nine-month-old "Sakkoty" date palm plantlets during the acclimatization stage. The effects of different application methods and concentrations of the mineral fertilizer Stimufol on vegetative and biochemical traits were evaluated after nine months of treatment. The fertilizer was applied either to the soil or as a foliar spray at concentrations of 0.5, 1.0, and 2.0 g/L, with additional combinations of soil and foliar application. Fertilization was conducted at two different intervals (every 2 or 4 days). The results revealed that the combined soil and foliar application of Stimufol at 2 g/L significantly increased total leaf number, pinnate leaf count, and overall plant vigor compared to other treatments. No significant differences in vegetative traits were observed between the two fertilization intervals. All fertilization treatments enhanced total and reducing sugar content, chlorophyll A and B, total amino acid content, and NPK percentage. However, extending the fertilization interval to four days reduced these biochemical parameters. Overall, soil fertilization alone or in combination with foliar application was more effective in promoting plant growth and nutrient accumulation than foliar application alone.