Soil in Karanganyar is dominated by alfisols which still requires a nutrient supply due to low levels of organic matter and nutrients needed by plants, including P due to high Ca levels resulting in P fixation. This research aimed to determine the appropriate dose of SP36 fertilizer to increase yields and growth of sweet maize on alfisol soil. The research was conducted in Sukosari Village, Jumantono District, Karanganyar Regency in June-September 2023. The method used was a Randomized Completed Block Design (RCBD) with one treatment factor, that was SP36 fertilizer level (0, 100, 200, 300, 400 kg ha-1) with 5 replications. Data analysis used analysis of variance and if significant, continued using Duncan’s Multiple Range Test (DMRT) at the 5% level. The results showed that the application of 200 kg ha-1 of SP36 fertilizer was the best dosage and recommended for application to sweet maize due to able to increase the length of the cob at 11 Week After Plant (WAP). 100 kg ha-1 of SP36 was able to increase sweet maize growth for dry weight of shoots.