From Concept to Cultivation: Building and Utilizing Deep Flow Technique (DFT) Hydroponics for Homegrown Urban Farming

Abstract

The rapid growth of the population has increased the need for urban farming to provide food sources for residents. One innovative approach in urban farming is vertical farming, which can be implemented in urban areas with limited space. Hydroponics, a method that uses nutrient solutions instead of soil as the growing medium, is a prominent example of vertical farming. Among the various hydroponic systems, the Deep Flow Technique (DFT) is commonly utilized, characterized by a nutrient solution that flows through the installation at a specific depth. We have developed a DFT hydroponic installation constructed from lightweight steel and 3-inch PVC pipes, featuring 100 planting holes. This installation model is suitable for cultivating Brassica rapa, achieving a biomass productivity of 131.88 ± 12.35 grams per plant, which is higher than that obtained with the wick hydroponic system. The DFT system offers several advantages over the Nutrient Film Technique (NFT) and wick systems, including a deeper nutrient solution that reduces the need for continuous electricity and minimizes temperature fluctuations. Furthermore, the flowing nutrients in the DFT system ensure the maintenance of dissolved oxygen levels during cultivation. Moreover, several improvements can be applied to the DFT hydroponic system such as using a shallower nutrient solution depth and implementing microbubbles in the aeration system. These benefits make the DFT system well-suited for vertical farming in residential areas.