Humic Acid

The part of humus which is soluble in water. It is typically dark brown to blackish in colour. Humic acid can be extracted, with a solution of sodium hydroxide, from any material containing well-decomposed organic matter, such as compost. This extractant helps to dissolve most of the organic matter. The solution is then acidified to a pH of about 2, which flocculates the organic material from the liquid portion to create humic acid. It is very resistant to any further breakdown. The remainder in solution is fulvic acid.