Mineral fertilization is difficult in rural areas due to the very high price of chemical fertilizers. However, organic waste, which sometimes disrupts the environment, can boost plant production. This investigation aims to determine some optimal conditions for fertilizing oil palms using ash from oil mill boilers to improve palm fruit production. To do this, different doses of this ash were tested on oil palm trees in production. Agronomic, physical, and agro-climatic parameters were evaluated. The results showed that fertilization using this ash, regardless of the dose, contributed to improving palm fruit production. To optimize this fertilization, a dose of 5 kg of this ash per palm tree, a significant amount of fine elements in this ash, and adequate levels of agro-climatic parameters are required.