Use of Ozone in Hydroponic Systems for Leafy Vegetables: Recent Evidence and Future Perspectives

Abstract

Hydroponic agriculture has become established over recent decades as a sustainable production alternative in response to challenges related to food security, resource-use efficiency, and the growing demand for safe and high-quality food. Within this framework, leafy vegetables such as lettuce (Lactuca sativa), spinach (Spinacia oleracea), and chard (Beta vulgaris) are of particular relevance due to their short production cycles, high commercial demand, and significant nutritional value. The objective of this review was to critically analyze recent advances and future perspectives regarding the application of ozone in the hydroponic production of leafy vegetables. To this end, a systematic review of scientific literature published between 2019 and 2024 was conducted using indexed databases, including Scopus, Web of Science, ScienceDirect, and SciELO, as well as the Google Scholar platform. Combinations of keywords related to ozone, hydroponics, leafy vegetables, and postharvest quality were employed, while studies not related to hydroponic systems or published outside the established time frame were excluded. The results indicate that ozone, when applied at properly controlled doses, significantly contributes to enhanced plant growth, improved biosecurity of hydroponic systems, and preservation of postharvest quality. However, the evidence also demonstrates that excessive or poorly calibrated exposure can induce oxidative stress and cause tissue damage in crops. In addition, relevant technological advances were identified, including the use of ozone micro- and nanobubbles and their integration with complementary technologies aimed at optimizing application efficiency and safety. Overall, the analyzed literature allows the conclusion that ozone represents a promising tool for the development of sustainable hydroponic systems. Nevertheless, its large-scale adoption requires the standardization of crop-specific application protocols, taking into account dosage, exposure time, and operational conditions, in order to maximize benefits while minimizing adverse effects.