Moringa Leaf Extract (MLE) as a Potential Bio Stimulant in Vegetable Production: A Review

Vegetable production faces increasing pressure to improve crop productivity and produce quality while addressing concerns related to chemical inputs, resource limitations and environmental sustainability. Plant-derived biostimulants have received attention as complementary inputs, particularly where materials can be sourced and prepared locally. This review examines the reported use of moringa (Moringa oleifera) leaf extract (MLE) as a biostimulant in vegetable crops, with emphasis on preparation methods, application practices and possible physiological effects. The literature discussed covers bitter gourd, brinjal, cabbage, pepper, cauliflower, cherry tomato, chilli, okra and onion. Reported responses include changes in germination, vegetative growth, flowering, fruit or seed yield, and selected crop-quality attributes. The composition of moringa leaves, including mineral nutrients, vitamins, phenolic compounds and phytohormones, provides a basis for considering potential mechanisms of action. The review also describes aqueous, solvent-based and pressurised hot-water extraction methods and the use of foliar application or seed priming. However, the magnitude and direction of reported responses differ across crop species, extraction methods, concentrations, application schedules and growing conditions. In particular, the available evidence does not support applying a single treatment protocol uniformly across vegetable crops. Further crop-specific work is needed to clarify appropriate leaf maturity, extract preparation, spray concentration and application timing. MLE may therefore serve as a complementary input in vegetable production, subject to locally validated application practices.