In the implementation of fertilization, only about 50% of the fertilizer can be absorbed by plants while some are degraded or drifted by groundwater so that fertilization becomes inefficient which will also pollute the environment with the content of N, P, and K. The loss of N as nitrogen gas due to denitrification is up to 30–40%, the loss of N as ammonia gas due to volatilization is about 10–20, the loss of N as nitrate due to the washing by water flow is about 44%, and erosion can reach 45%. One solution to this problem is using a slow release fertilizer (SRF) where the nutrient is released slowly within a certain time. The SRF technology modifies the fertilizer utilizing chitosan coating on granule surface of the fertilizer. Liquid chitosan is used for coating and it is sprayed on the surface of fertilizer granule in the rotary pan granulator. It is found that the resistance of the chitosan coated fertilizer in the water is about 3–6 months. The characteristics of the nutrients released from SRF NPK 16‐16‐16 coated with chitosan are about 103.26 mg nutrients of N, 21.8 mg nutrients of P, and 65.62 mg nutrients of K within a month of immersion time.