A field experiment was conducted in spring-summer season in Central Vietnam to investigate the effect of different application levels (e. g. 25, 50, 75 and 100 l/ha) of organic foliar nutrient solution named BD1 which was mixed from molasses, watermelon extract and aglutamic solution on the growth and yield of lettuce plants. Growing time, plant height, number of leaves per plant, canopy diameter, biomass and yield were investigated. The results indicated that the plant treated with high levels of 50, 75 and 100 l/ha had a positive effect on the development, growth and yield of lettuce. Spraying at the level of 100 l/ha was an optimal level which gained highest growth and yield. As a result, farmers are recommened to use the BD1 as a nutrient supplement to lettuce in organic agricultural production.