Overview Algen Extract from H&G is a Norwegian sea kelp extract that contains an abundance of macronutrients, trace elements, amino acids, natural anti biotics and vitamins. General Information Sea Kelp extracts have been used for decades as a source of nutrition for your plants. Growers using kelp based extracts note healthy, vigorous growth and an overall healthier root zone. Algen Extract is created via cold-pressing which keeps the biomolecules active.