Ingredients
Humic acids are complex organic carbon compounds formed over 70+ million years from the slow decomposition of ancient plant matter under geological pressure. Extracted primarily from leonardite shale — a soft, oxidized coal found near the earth’s surface — humic acids function as a nutrient multiplier in soil: they don’t deliver significant NPK themselves, but they dramatically increase the availability of every other nutrient present.
Humic acids are the high-molecular-weight fraction of humic substances — dark, amorphous organic molecules with complex structures containing carboxyl (-COOH), phenolic (-OH), and carbonyl (C=O) functional groups. These functional groups give humic acids an extraordinary capacity to bind and exchange nutrient cations — essentially making them the most powerful natural chelating agents available to organic growers.
Leonardite shale, the primary commercial source, forms when prehistoric plant matter undergoes partial coalification — enough geological pressure and time to concentrate the organic carbon, but not enough to form true coal. Major leonardite deposits exist in North Dakota, New Mexico, and Canada. The material is mined, oxidized, and alkali-extracted to produce concentrated humic acid products.
Humic acids contribute three critical properties to organic soil systems:
Chelation: Humic acid molecules wrap around micronutrient cations (iron, zinc, manganese, copper, boron) and hold them in plant-available form. Without chelation, these micronutrients precipitate into insoluble compounds at pH levels above 6.5 — exactly the pH range most vegetables prefer. Humic acid chelation keeps micronutrients available even when soil chemistry would otherwise lock them out.
Cation exchange capacity (CEC): Adding humic acids to soil increases CEC by 30-50% — meaning the soil can hold and exchange significantly more nutrient cations with plant roots. This is why soils high in organic matter (which contains humic substances) are more fertile than mineral soils with identical nutrient levels.
Root stimulation: Humic acids exhibit auxin-like biological activity, promoting root cell elongation and lateral root branching. Studies have demonstrated 20-50% increases in root mass when humic acids are applied to the root zone — more roots means more nutrient uptake surface area, compounding the chelation benefit.
Humic substances are classified by molecular weight: humic acids are the high-molecular-weight fraction (dark brown to black, insoluble below pH 2), fulvic acids are the low-molecular-weight fraction (golden to amber, soluble at all pH levels), and humins are the insoluble residue.
Fulvic acids are smaller molecules that penetrate plant cell membranes directly, delivering chelated nutrients through foliar application. Humic acids are too large for foliar uptake but excel in the soil environment, where their size allows them to bind more nutrients per molecule and persist longer in the root zone (humic acids resist microbial decomposition for years).
Humic acids are a component of the nutrient availability fraction in our 25-ingredient fertilizer blend, present in all Daley Organics soil products. Their role isn’t to deliver NPK — it’s to ensure that the NPK and micronutrients from the other 24 ingredients actually reach plant roots in available form.
Consider the other ingredients in the blend: blood meal provides nitrogen, bone meal provides phosphorus, kelp meal provides potassium and trace minerals, greensand provides iron and potassium, glacial rock dust provides 30+ trace minerals. Humic acids chelate and protect every one of those nutrients from lockout, precipitation, and leaching — functioning as the biological glue that holds the entire fertilizer system together.
At our Grants Pass soil yard on Monument Drive, we source leonardite-derived humic acid products that analyze at 70%+ total humic acid content.
For granular humic acid products, incorporate 1-2 lbs per 100 square feet into the top 6-8 inches before planting. For liquid humic acid concentrates, dilute per manufacturer instructions and drench the root zone at planting and monthly thereafter. For compost enhancement, add 1 lb of granular humic acid per cubic yard of compost during the curing phase.
Humic acids are most effective in soils with existing nutrient content that needs to be made more available. Applying humic acids to nutrient-depleted soil has minimal benefit — the chelating agent needs something to chelate. This is why Daley Organics includes humic acids as part of a 25-ingredient system, not as a standalone product.
Common Questions
Humic acids chelate micronutrients (keeping them plant-available even at pH levels that would normally lock them out), increase cation exchange capacity by 30-50%, and stimulate root growth through auxin-like activity that promotes root cell elongation and lateral branching.
Humic acids are high-molecular-weight compounds that work in soil to chelate nutrients and increase CEC, persisting for years. Fulvic acids are smaller molecules that penetrate plant cell membranes directly, making them effective for foliar feeding. Both are fractions of humic substances from decomposed plant matter.
Commercial humic acids are extracted from leonardite shale — a soft, oxidized coal formed over 70+ million years from prehistoric plant matter under geological pressure. Major deposits exist in North Dakota, New Mexico, and Canada. The material is mined and alkali-extracted without chemical synthesis.
No. Humic acids have negligible NPK content. Their value is as a nutrient multiplier — they chelate and protect micronutrients from lockout, increase the soil's capacity to hold and exchange nutrients (CEC), and stimulate root growth. They make every other nutrient in the soil more available.
Adding humic acids to soil increases cation exchange capacity by 30-50%, meaning the soil can hold and exchange significantly more nutrient cations with plant roots. This is equivalent to converting a sandy soil's nutrient-holding capacity to that of a loamy soil.
Used In Our Blends
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