Grow More® Mendocino Amber Humic Fulvic Acid — 2.5 gal

Leonardite-Derived Biostimulant, 2.5 gal, for Nutrient Uptake and Soil Biology

Synthetic fertilizer alone doesn't feed the soil biology that keeps nutrients cycling and available, and it can't chemically carry locked-out minerals into a root the way a humic and fulvic acid extract can. Grow More Mendocino Amber Humic Fulvic Acid is a liquid extract derived from Leonardite, one of the most concentrated natural sources of biologically active humic substances, delivering a slow-release biostimulant effect while feeding beneficial soil microbes and bonding chemically to both positively and negatively charged nutrient molecules for more efficient translocation into the plant.

Available in 2.5 gal, Amber Humic is suited to coco coir, hydroponic systems, potting mixes, and native soils, and it is designed to be used alongside any existing fertilizer program.

Key Features & Benefits

• Leonardite-Derived Extract: Sourced from highly oxidized organic matter with an exceptionally high concentration of bioactive humic substances.
• Biostimulant via Auxin-Like Compounds: A slow release of auxin-like materials stimulates cell elongation, root development, and overall plant growth.
• Feeds Beneficial Soil Microbes: Humic and fulvic acids serve as a carbon substrate for beneficial soil bacteria and fungi.
• Ionic Bonding for Nutrient Uptake: Bonds with both positively and negatively charged nutrient ions, improving translocation across root membranes.
• 1.0% Humic Acid (Leonardite): A consistent, labeled concentration for predictable, repeatable biostimulant activity.

Who Should Use This

Growers who want to maximize nutrient utilization efficiency, support soil biology, and encourage the natural growth responses of a biologically active root zone are the direct fit — particularly those transitioning toward more regenerative practices, or running systems where root-zone biology and nutrient efficiency are a priority. It pairs well with other Mendocino supplements, including N-Cal-Mag, Myco Grow, and Hawaiian Big Bud.

About Grow More Inc.

Grow More Inc. has produced fertilizers and biological soil amendments since 1918, beginning as National Chemical Company in Hollywood, California and now headquartered in Gardena, California, with Amber Humic forming part of its Mendocino supplement line.

Frequently Asked Questions

What is Leonardite and why is it used as a humic acid source?

Leonardite is a soft, oxidized form of lignite that forms as organic plant matter undergoes millions of years of geological pressure and oxidation. It's rich in humic and fulvic acids and is widely regarded as one of the highest-quality natural sources of concentrated humic substances.

What is the difference between humic acid and fulvic acid?

Humic acids are larger molecules that improve soil structure, boost cation exchange capacity, and feed soil microbes over time. Fulvic acids are smaller and more soluble, acting as natural chelators that carry bound nutrients directly into plant tissue.

How does Amber Humic improve nutrient uptake?

The fulvic acid fraction forms soluble complexes with mineral nutrients, binding both positive and negative ions, and carries those complexes across the root cell membrane in a process sometimes described as a trojan-horse effect. This makes nutrients that pH or competing ions might otherwise lock out far more available to the plant.

Can Amber Humic be used as a foliar spray?

Yes, diluted Amber Humic can be applied as a foliar spray for rapid absorption through leaf surfaces. Apply during lights-off or cooler conditions to reduce evaporation and improve coverage on leaf undersides.

How often should I apply Amber Humic?

It can be applied at every watering as a low-dose addition to nutrient solution, or as a periodic soil or media drench. Consistent low-dose application generally outperforms infrequent high-dose treatments as a biostimulant and microbial food source.