Why humic and fulvic acids matter — and how they differ

Humic and fulvic acids are both humic substances, but several key differences explain their distinct benefits. They differ in carbon and oxygen content, acidity, degree of polymerisation, molecular weight and colour. Humic acids have large molecules and work best in the soil, creating favourable conditions for plant development. Fulvic acids work well both in the soil and in foliar nutrition, helping deliver nutrients through cell membranes. The best results are achieved when humic and fulvic acids are used together.

Humic acids

Humic acids are large, black molecules containing carbon, oxygen, nitrogen, hydrogen and phosphorus. Their exact composition depends on their source. They do not dissolve under acidic conditions but dissolve well in alkaline soils. Humic acids make otherwise unavailable soil nutrients accessible to plants and help prevent toxic metals and harmful substances from entering them. They also stimulate soil microorganisms, improve water-holding capacity and support root development. By increasing plant cell-wall permeability, they improve nutrient uptake. Humic acids are a key component of a well-functioning soil system: a bridge between the soil and the plant.

Fulvic acids

Fulvic acid molecules are much smaller than humic acid molecules and are soluble at any pH. They contain carbon, hydrogen, oxygen and nitrogen and have a golden colour. With approximately twice the oxygen content of humic acids, they are more biologically active. Their main benefit is improved nutrient uptake. They are highly effective carbon-containing chelating compounds and act as carriers, transporting nutrients from the soil into the plant.

Both humic and fulvic acids are important for healthy plants. Using only one changes the benefits obtained. They work together to create conditions for optimal growth and development. For example, humic acids increase cell-membrane permeability, allowing fulvic acids to transport substances into the plant more effectively. Humic acids also make nutrients available for fulvic acids to carry. Together, they improve water retention and stimulate root development more effectively.

Agronomist’s recommendations:

Humic and fulvic acids can be used throughout the growing season. For maximum effect, apply them from the end of flowering until ripening, with each irrigation or fertiliser application. This supports soil microbial activity and, most importantly, helps plants make the best use of nutrients in the soil.

Recommended products: Fulvitec (Nufol, Spain) | Naturvital 15 (Daymsa, Spain) | Rootip Start (Altinco, Spain)

Article prepared by:

Agronomist: Nika Akhobadze

Source: http://www.earthgreen.com/humic-vs-fulvic-acids