Effects of Vermicompost, Mineral Fertilization, and Harvest Timing on Growth, Yield, and Quality Attributes of Napa Cabbage in Substrate‐Based Cultivation

Nutrient management is important for maintaining productivity and quality in soilless vegetable production. This study independently evaluated vermicompost (VC) and mineral fertilizer rate in Experiment 1 and harvest time and mineral fertilizer rate in Experiment 2 for Napa cabbage ( Brassica pekinensis cv. Rado 67) under greenhouse conditions. Two independent 2 × 4 factorial experiments were conducted using a completely randomized design (CRD). Experiment 1 evaluated VC (0 and 100 g pot ⁻¹ ) and four mineral fertilizer rates, whereas Experiment 2 evaluated harvest time (50 and 60 days after transplanting [DAT]) and the same fertilizer rates under a uniform VC application of 100 g pot ⁻¹ . In Experiment 1, VC and mineral fertilizer rate significantly affected plant growth, yield, and selected quality attributes. The highest yield was obtained with 100 g pot ⁻¹ VC and F ₄ (80–40–60 kg ha ⁻¹ N–P ₂ O ₅ –K ₂ O), reaching 233.63 g pot ⁻¹ . In Experiment 2, harvest time and fertilizer rate significantly affected plant growth and total yield, with a significant harvest time × fertilizer rate interaction. The highest treatment‐combination yield was obtained at 60 DAT with F4, reaching 564.00 g grow bag ⁻¹ . Under the highest‐yielding treatment in Experiment 1, nitrate concentration was 109.80 mg NO ₃ ⁻ kg ⁻¹ fresh weight, while Escherichia coli and coliforms were below the detection limit (<1 most probable number [MPN] g ⁻¹ ). Overall, VC and mineral fertilizer affected crop performance in Experiment 1, whereas harvest time and mineral fertilizer rate affected productivity in Experiment 2 under the tested conditions.