What is fulvic acid exactly? Fulvic acid is a black powder mined from peat and coal deposits. It is in fact a mixture of several acidic organic chemicals and not just one compound. Fulvic acid is biochemically active and has some effect on plant growth and development. The chemicals are the products of decay from plants that lived millions of years ago. GT Fulvic is a concentrated water based solution of fulvic acid. It needs to be diluted before use.