A factorial controlled experiment was carried out at the College of  Medicinal and Industrial plants, Department of Medicinal and Industrial Plants, University of Kirkuk, This study was designed to systematically assess the individual and interactive effects of high-potassium fertilization and planting method on the vegetative growth performance of fennel (Foeniculum vulgare L.). A factorial experiment was implemented under field conditions using two planting methods (row sowing and broadcasting) and three concentrations of high-potash fertilizer (0, 2, and 3 g L⁻¹). The treatments were arranged in a randomized complete block design (RCBD) with three replicates to ensure experimental precision and minimize environmental variability. Statistical analysis was conducted using analysis of variance (ANOVA), and treatment means were separated according to Duncan’s Multiple Range Test at a significance level of P ≤ 0.05. The results demonstrated that increasing high-potassium fertilization significantly enhanced all evaluated growth parameters. The highest fertilizer concentration (3 g L⁻¹) produced the greatest values for plant height, number of branches per plant, stem diameter, days from planting to 50% flowering, and number of inflorescences. Furthermore, a significant interaction effect between fertilization level and planting method was observed, indicating that the combined application of optimal potassium supply and appropriate planting configuration maximized vegetative growth and reproductive development.