Garlic is a commodity crop that has a high economic value so that it has an attraction to cultivation. the decline in garlic production is caused by problems often faced by farmers, namely the decline in chemical, biological, and physical properties of the soil resulting in non-optimal garlic growth. This study aims to determine the effect and find the concentration of GA3 and the dose of silica fertilizer on the growth and yield of garlic. The research was conducted in Dukuh Pancot, Kalisoro Village, Tawangmangu District, Karanganyar Regency, Central Java as garlic cultivation; Soil Chemistry and Fertility Laboratory, Faculty of Agriculture, Sebelas Maret University for soil analysis and Crop Production Management Ecology Laboratory, Faculty of Agriculture, Sebelas Maret University for garlic yield measurement from May-September 2024. The method used was a factorial Randomized Complete Group Design with two factor and three replications. The first factor was GA3 (0, 60, and 120 ppm). The second factor was silica fertilizer (0, 15, and 30 mL). Variables observed included environment (soil, air temperature, air humidity, light intensity, and rainfall), growth (plant height, number of leaves per clump, fresh weight of stover, and dry weight of stover) and yield (bulb diameter, number of cloves, fresh weight of bulb per clump, dry weight productivity of bulb per ha). Environmental data (air temperature, air humidity, rainfall, and light intensity) and preliminary soil analysis were analysed descriptively. Garlic growth and yield data were analysed using Analysis of Variant (ANOVA) at the 95% significance level to obtain the effect of all observation variables. If the results showed an effect, orthogonal polynomial regression was tested to find the optimum concentration of GA3 and dose of silica fertiliser. The results showed that GA3 and silica fertilizer had an interaction on the fresh weight of garlic stems with the optimum concentration without the use of GA3 and 5.01 mL silica fertilizer. GA3 concentration of 120 ppm can increase the number of garlic leaves. The optimum dose of 18.50 mL silica fertilizer tends to increase the height of garlic plants.