The present invention relates to an organic method for production of spirulina, the method comprising steps of: a)mixing oil cakes as a nitrogen source with water and stirring continuously in an anaerobic tank b) adding microorganisms to the oil cakes for fermentation of oil cakes which helps for the release of nitrogen to the culture and helps for protein synthesis in the algae c) maintaining a temperature between 25OC to 35OC for a time duration of 7 to 15 days in anaerobic conditions without sunlight leading to fermentation of the organic contents and release the nitrogen available for spirulina d) transferring the supernatant liquid to second tank in anaerobic condition e) transferring the supernatant liquid from second tank to the spirulina tanks f) adding spirulina inoculums to the spirulina tank g) stirring the contents of spirulina tank in presence of natural sun light for 15 days till an optical density of the culture reaches the value of 0.7 to 1.0 h) observing the parameters such as microscopy of cell morphology, OD,pH,HCO3, total alkalinity and water depth in the tank on the daily basis i) observing and maintaining nutrient ingredients in the spirulina tank at a regular interval j) harvesting the spirulina from the spirulina tank k) washing the spirulina with water and l) drying the spirulina of step (k) to obtain dry powder of spirulina.
