Monitoring The Performance Of An Underground Hydroponic Farm

Abstract

As urban populations are set to rise by 2.6 billion by 2050, placing greater strain on the availability of natural resources in cities, there is growing interest in hydroponics as a resource and space efficient method to grow food closer to point of use. While controlled environment agriculture (CEA) is increasingly being used in greenhouses, one cannot rely on models alone to create optimal environments with minimal resource use. Growing Underground is a unique case in London, where WW2 air raid shelters, derelict since the 1960s, have been transformed to house a hydroponic farm. This paper presents the case study of monitoring this start-up hydroponic farm to improve crop growth and minimise energy use. It shows the development of monitoring techniques through a wireless sensor network and the manually recording of data. A set of indicative parameters is derived from the monitored variables in this three-year long study to analyse dependencies and correlations. The data are organised into environmental parameters (temperature, relative humidity, change in CO2), control parameters (energy use, water use, ventilation, lights), and crop growth parameters (crop health, yield and number of growing days). The relationships found between the variables are then used to understand how to improve the performance of the farm, namely, to adapt farm configurations, derive the optimal growing conditions, and improve the resource use efficiency.