The composition of the Aerogarden nutrient tablets is according to the gourmet herb seed kit on page 31 of the seed kit manual. It is mainly mineral salts that compose the aerogarden nutrient tablets, which provide the 13 macro and micro nutrients that all plants and herbs require in just the right proportions for herb plants. Tablets also contain:Seaweed which provides a 70 micro nutrient boost and trace elements.A buffer allowing the use of tap water with the plants.A binder, holding the tablet together.A commonly asked question is whether the nutrients are organic?The Aerogarden nutrient tablets are indeed organic, according to current American Association of Plant Food Control Officials (AAPFCO) standards.The nutrients have not as yet been tested by British Organic standards (BOS) however this is something that Aerogrow is aiming to have done soon.