Objective: To evaluate the effect of marine brown alga Sargassum polycystum extract on growth and biochemical parameters of Vigna radiata and Vigna mungo. Methods: Different concentrations of algal extracts (0.5%, 1.0%, 2.0%, 3.0%, 4.0%, and 5.0%) were prepared and applied to the crops at every 10-day intervals under natural conditions. After 30 d, the plants were harvested to evaluate the growth and biochemical parameters. Results: Seaweed liquid fertilizers treated seedlings showed maximum growth in 3.0% concentration when compared to the untreated seedlings. Similarly, biochemical parameters such as photosynthetic pigments, protein, reducing sugar, total sugar and amino acids exhibited increases in 3.0%concentration seaweed extract. Decreases in growth and biochemical parameters were noticed in concentrations higher than 3.0%. Conclusions: Presence of micronutrients and growth regulating substances in the liquid extract help healthier and faster productivity of the crop.