Grow More® Mendocino Amber Humic Fulvic Acid — 6 gal

Leonardite-Derived Humic and Fulvic Acid Biostimulant for Enhanced Plant Health and Soil Biology

Grow More® Mendocino Amber Humic Fulvic Acid is a liquid humic and fulvic acid extract derived from Leonardite — one of the most concentrated natural sources of biologically active humic substances available. This powerful biostimulant promotes plant growth through a slow release of auxin-like compounds, stimulates a thriving soil microbiome, and improves nutrient uptake efficiency through its unique ability to chemically bond with both positively and negatively charged molecules — facilitating their efficient translocation into plant tissues. Available in 6 gal.

Key Features & Benefits

• Leonardite-Derived Humic and Fulvic Acid: Extracted from highly oxidized, naturally occurring organic matter with an exceptionally high concentration of bioactive humic substances — providing the full spectrum of biostimulant activity associated with premium humate products.
• Biostimulant Effect via Auxin-Like Compounds: The slow release of auxin-like materials in Amber Humic biologically stimulates cell elongation, root development, and overall plant growth in ways that synthetic fertilizers alone cannot replicate.
• Feeds Beneficial Soil Microbes: Humic and fulvic acids serve as a premium carbon substrate for beneficial soil bacteria and fungi, promoting a thriving soil ecosystem that improves long-term nutrient cycling and plant health.
• Ionic Bonding for Enhanced Nutrient Uptake: The ability to bond with both positively charged cations (Ca²⁺, Mg²⁺, Fe²⁺) and negatively charged anions facilitates the translocation of bound nutrients across root cell membranes and throughout the plant more efficiently than unchelated forms.
• Universal Growing System Compatibility: Suitable for use with coco coir, hydroponic systems, potting mixes, and native soils — and recommended for use in conjunction with any fertilizer program.
• 1.0% Humic Acid (Leonardite): Contains a consistent, labeled concentration of 1.0% humic acid from Leonardite for predictable, reproducible biostimulant activity.

Who Should Use This

Amber Humic is an ideal addition to any growing program for growers who want to maximize nutrient utilization efficiency, support soil biology, and enhance the natural growth responses that result from a biologically active root zone. It is particularly valuable for growers transitioning toward more biological and regenerative practices, and for any system where nutrient efficiency and root zone biology are priorities.

Compatibility

Amber Humic is compatible with all growing substrates — coco coir, potting mixes, hydroponic systems, and native soils — and can be used alongside any fertilizer program. Add to your nutrient reservoir or irrigation water at the recommended rate. It pairs well with other Grow More Mendocino supplements including N-Cal-Mag, Myco Grow, and Hawaiian Big Bud as part of a comprehensive biological growing program. Available in 2.5-gallon and 6-gallon sizes.

Frequently Asked Questions

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

Leonardite is a soft, waxy, oxidized form of lignite (brown coal) that forms when organic plant matter is subjected to millions of years of geological pressure and oxidation. It is exceptionally rich in humic and fulvic acids — the complex organic molecules responsible for the biostimulant and soil-conditioning properties of humate products. Leonardite is widely regarded as one of the highest-quality natural sources of concentrated humic substances available.

What is the difference between humic acid and fulvic acid?

Both are fractions of humic substances derived from decomposed organic matter. Humic acids are larger molecules that improve soil structure, increase cation exchange capacity, and feed soil microbes over time. Fulvic acids are smaller, more soluble molecules that cross plant cell membranes more easily, acting as natural chelators that carry bound nutrients directly into plant tissue for rapid uptake.

How does Amber Humic improve nutrient uptake?

The fulvic acid fraction of Amber Humic forms soluble complexes with mineral nutrients — binding to both positively and negatively charged ions — and carries those complexes across the root cell membrane via a process sometimes described as a “trojan horse” effect. This makes nutrients that might otherwise be locked out by pH or competing ions much 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 of fulvic acid–bound nutrients through leaf surfaces. Apply during lights-off or cooler conditions to minimize evaporation and ensure thorough coverage of leaf undersides where absorption is most efficient.

How often should I apply Amber Humic?

Amber Humic can be applied at every watering as a low-dose addition to nutrient solution, or as a periodic soil/media drench. As a biostimulant and microbial food source, consistent low-dose application is generally more effective than infrequent high-dose treatments.