The Effect of Growing Media Combinations and KNO₃ Fertilizer Doses on The Growth and Yield of French Breakfast Radish (Raphanus sativus L.)

Abstract

Radish (Raphanus sativus L.) is a horticultural crop with potential for urban farming, but its performance is influenced by growing media characteristics and nutrient availability. This study aimed to analyze the effects of growing media, KNO₃ fertilizer doses, and their interaction on the growth and yield of French Breakfast radish grown in polybags. The study was conducted from May to July 2026 using a factorial Completely Randomized Design with two growing media, namely soil + rice husk and soil + sand, and four KNO₃ doses (0, 0.75, 1.50, and 2.25 g polybag⁻¹), with four replications. Data were analyzed using analysis of variance followed by the 5% HSD test. The results showed a significant interaction between growing media and KNO₃ dose on leaf number growth rate and leaf number at 28 days after planting (DAP). The combination of soil + rice husk and 0.75 g KNO₃ polybag⁻¹ produced the highest values, at 0.21 leaves day⁻¹ and 7.75 leaves, respectively. Growing media significantly affected leaf number at 14 DAP and shoot-to-root ratio, while KNO₃ significantly affected fresh plant weight based on ANOVA. No significant effects were observed on tuber yield components. These findings imply that soil + rice husk combined with 0.75 g KNO₃ polybag⁻¹ may support vegetative growth, but cannot yet be recommended as an optimum treatment for increasing tuber yield.