Low-Cost Automation Framework for Sustainable Hydroponic Farming in Urban Poly Houses

Abstract

Urbanisation and shrinking arable land demand cost-effective, sustainable food production methods. This paper presents an open-source automation framework for hydroponic farming in urban polyhouses that achieves full functionality for under US $100. The system employs multi-parameter sensing (pH, EC/TDS, temperature, humidity, water level) and a dual-loop control strategy that sequentially regulates pH and nutrient dosing to avoid chemical antagonism. An ESP-NOW–based fail-safe maintains operation during internet outages, while a secure bilingual mobile app (Flutter, AES-256-GCM encryption) enables real-time monitoring and control. Three replicated 42-day nutrient film technique (NFT) trials with Coriandrum sativum yielded a 27.5% ± 3.2% increase in fresh weight and 82% water savings compared with manual control (p < 0.05). Economic analysis showed a 6.1-month break-even and 96 % ROI in year one. Results demonstrate that the proposed framework is a scalable, resilient, and economically viable solution for resource-limited urban agriculture.