The aim of this work was to study the effect of substrate disinfection and application of plant growth-promoting rhizobacteria (Bacillus subtilis) on the yield, quality and safety of watercress grown in a floating system. Substrate disinfection had a positive effect on plant development because it increased the shoot antioxidant capacity and general plant growth and decreased the colony-forming units of molds. In turn, inoculation with B. subtilis increased the antioxidant capacity but decreased the chlorophyll a, chlorophyll b, and carotenoid contents and did not affect the rest of the parameters measured. In conclusion, our results showed that the effects of substrate disinfection were more pronounced than those obtained by B. subtilis inoculation, suggesting that it would be more convenient to reserve the use of plant growth-promoting rhizobacteria for other conditions, such as abiotic stress.
