When will papaya leaf become fertilizer?

Yes, fertilizer can be made from dried papaya leaves.

Specifically, a fertilizer is intended to enrich soil by adding necessary nutrients. Nutrients such as nitrogen, phosphorus and potassium contribute to healthy soil and to healthy plants. Necessary nutrients are found in dried papaya leaves. In the process of decomposition, papaya leaves keep crumbling until all of their nutrients are released back into the soil. In dried and crumbled form, they therefore serve as fertilizer.