This study aims to determine the effect of applying organic cow dung fertilizer to the sediment soil of Kendari Bay as a planting medium on the changes in soil chemical properties and the growth of red chili (Capsicum annum L.). This research was conducted in Experimental Field II, and soil analysis was performed in the Analytical Chemistry and Nanoscience Testing Laboratory as well as the Nano Technology Laboratory, Halu Oleo University. The study took place from August to December 2022. This research used a Randomized Block Design (RBD) with 6 treatments, namely without cow manure (M0); cow manure 100 g per polybag (M1); cow manure 200 g per polybag (M2); cow manure 300 g per polybag (M3); cow manure 400 g per polybag (M4); cow manure 500 g per polybag (M5), repeated 3 times, resulting in 18 experimental units. The results of the study showed that there were changes in soil chemical properties due to the application of cow dung fertilizer to the sediment soil of Kendari Bay, and an increase in growth in red chili plants. Total N increased from 0.01 to 0.08%, available P increased from 5.64 to 19.34 ppm, available K increased from 18.42 to 25.58 mg 100-1, as indicated by the increase in plant height and leaf number. The tallest plants were obtained in the treatment with 500 g per polybag (M5), and the highest number of leaves was obtained in the treatment with 500 g per polybag (M5).