Chlorella is a single-celled green microalgae that derives its name from Latin “chloros,” meaning green, and “ella,” meaning small. It has been used in food supplements because of its amino acids, carbohydrates and fat content, and its fat has also been utilized in the “bio-oils” industry. Only recently has the value of Chlorella been researched and documented as a plant fertilizer. Chlorella’s abundance of amino acids and carbohydrates, trace amounts of vitamins and polypeptides, and trace amounts of plant growth hormones such as auxins, gibberellins, and cytokinins, all contribute to its value in hydroponics. Many new studies of Chlorella are centered on the polysaccharides exuded by algal species that have the ability to complex many metal ions including zinc and copper, which are important trace minerals in plant growth.