The present invention relates to a product Kappaphycus alvarezii seaweed sap free of Gibberellic acid (GA3) and its method of preparation. Kappaphycus alvarezii seaweed sap is a plant stimulant found to enhance yield and quality of a number of crops. Besides containing many macro- and micro-nutrients, there are many plant growth hormones present in Kappaphycus alvarezii sap. It has been observed that pristine Kappaphycus alvarezii sap and GA3 free sap enhanced grain yield but surprisingly selective removal of GA3 from the pristine sap had profound stimulating effect on total dry above ground biomass yield of maize over and above the pristine sap. Upon seed treatment with GA3 free sap, &alpha-amylase enzyme activity in the germinating seed of mung bean is found to be increased. The foliar spray of GA3 free sap on tomato plants upregulated disease responsive genes (PR-3 and PR-5) as compared to pristine sap.
