Vermiliquer as a biostimulant and antioxidant in hydroponic lettuce (Lactuca sativa) production

The use of vermiliquers obtained from earthworms in hydroponic crops is well received as an alternative for the fertilisation of leafy vegetables. Vermiliquer boosts growth and defence compounds and increases the uptake of nutrients and minerals by plants. The growth and enzymatic activities related to stress and phenolic compounds were explored in hydroponic lettuce crops treated with different concentrations of vermiliquer. The treatments consisted of three different vermiliquer products, a mesh vermiwash, a direct vermiwash, and a vermileachate, and their combinations as a complement for the complete fertilisation. The addition of vermiliquer to hydroponic lettuce affected the leaf and root fresh weight, and the reactive oxygen species-like superoxide dismutase (SOD) or phenylalanine ammonia-lyase (PAL). Vermileachate (Vl) plus direct vermiwash treatment caused higher growth in lettuce leaf and roots from the first week indicating a biostimulant effect, indicating that it was an effect biostimulant. Vl caused the highest enzymatic SOD and PAL activity, indicating that it was an effect elicitor. In summary, vermiwash proved to improve the hydroponic lettuce crop and enzymatic activities related to stress.