Plant biostimulants can be derived from various sources and may draw from a variety of different materials as their key functioning ingredients.
These can include but are not limited to: Microbes (e.g., bacteria, fungi), biochemical materials (e.g., microbial metabolites), organic acids (e.g., amino acids, humic acids, fulvic acids), proteins, enzymes, organic matter extracts (e.g., kelp/seaweed or plant extracts, botanical oils), chemical salts, vitamins, elements, small molecules and other similar materials.