In oil palm plantations, the application of secondary nutrients, especially calcium and sulfur is often negligible due to the focus on merely primary nutrients and magnesium. Calcium is responsible for proper plant cell division and for strengthening cell walls while sulfur improves the oil synthesis rate in oil palm. Polyhalite (K2SO4·MgSO4·2CaSO4·2H2O) is a natural marine evaporite mineral produced by successive marine evaporation events throughout history. Its huge potential as a potassium fertiliser, due to its very low quantities of chlorine but richness in potassium, calcium, and magnesium, has attracted its use in various crops to achieve higher yields and better-quality crops. In addition to potassium, magnesium fertilisation can increase crop yield and quality. Previous studies focus on applying Polyhalite in cash crops and are less prominent in the oil palm. Therefore, this study aims to evaluate the vegetative growth performance of Polyhalite on oil palm aged one-year-old in addition to the conventional programme. Results showed that applying 0.3 kg ERP + 0.3 kg AgCOTE 18/6/8/2+ME + 0.3 kg Polyhalite into planting holes during transplanting the oil palm seedlings in the field is most cost-efficient while delivering the same vegetative growth compared to the conventional practices.