Aprilia, R. and Miftakhurrohmat, A. 2026. Cultivation of Pakcoy Mustard (Brassica rapa L.) in a Hydroponic System in a Surabaya Vegetable Garden: Analysis of Plant Nitrogen Requirements: Budidaya Sawi Pakcoy (Brassica rapa L.) pada Sistem Hidroponik di Kebun Sayur Surabaya: Analisis Kebutuhan Nitrogen Tanaman. Procedia of Engineering and Life Science. 8, 2 (Feb. 2026). DOI:https://doi.org/10.21070/pels.v8i2.2520.