Humic Acid Fertilizer Easily Add It For Your Best Plants, How To Use It

Humic Acid for Plants

what healthy soil with humic acids looks like
monoculture field of sunflowers growing By Diego Delso

What is humic acid?

Humic acid gets created by the final breakdown of decaying plant and animal matter from microbial degradation.

The organic acids get formed from the chemical and biological humification of the plant and animal matter through the biological activities of micro-organisms.[1]

Humic acids exist naturally in soils, peats, oceans, and freshwaters and are complex molecules.

Humic acids get found in high concentrations in the layers of Leonardite.

What is Leonardite?

Leonardite is a sedimentation layer originally deep in the earth's crust. It has been exhumed to near-surface locations over many years.

Leonardite is organic matter that has not yet reached the state of coal and has a high degree of oxidation. It takes millions of years for the decomposition of these concentrated organic acids.

While humic acid can get artificially created by chemically or mechanically oxidizing Leonardite, natural sources are much more economical.[1]

Humic Acid Fertilizer Benefits

Why is humic acid good for the soil?

  • 1) Better Soil Structure. In light sandy soils, it prevents nutrient loss. In compacted and heavy soils, it helps to aeration and better water retention.
  • 2) It helps you to increase the aeration and workability of your soil.
  • 3) Improved Water Retention helping resist drought
  • 4) Darkens soil color, helping the absorption of the suns energy
  • 5) Holds onto ionized nutrients, preventing them from leaching away
  • 6) Regulates the pH value of soils. Neutralizes both acid and alkaline soils
  • 7) Increases buffering properties.
  • 8) Reduces the availability of toxic substances in soils by decreasing high salt contents.

Why is humic acid good for plants?

  • 1) It Increases Cell Wall Permeability. It thickens the cell walls in fruits and prolongs their storage time.
  • 2) Increased available nutrient uptake
  • 3) Increase soil microbial activity
  • 4) Increases availability of nutrients in Soil (conversion of nutrient elements (N, P, K + Fe, Zn) to forms available for our plants)
  • 5) Stimulates root growth, especially vertically, and enables better uptake of nutrients.
  • 6) Increases root respiration and root formation.
  • 7) Crop Production gets increased. Stimulates plant growth (higher biomass production) by accelerating cell division, increasing the rate of development in root systems, and increasing the yield.
  • 8) Decreased Disease and Infestation
  • 9) Decreased Need for Fertilizer
  • 10) Easy to apply
  • 11) Increases the quality of your harvest while improving its physical appearance and nutritional value.
  • 12) Promotes the development of chlorophyll, sugars, and amino acids in plants and aid in photosynthesis
soil with humic acids and plants growing
What a healthy soil should look like By Natural Resources Conservation Service Soil Health Campaign

Humic Acid Fertilizer Disadvantages

  • 1) It is a mined substance. Just like coal or fossil fuels, humic acids get collected through mining. It is much more environmentally friendly if you created home compost or green manure yourself instead.
  • 2) Cost. While it is cheaper than going out and buying compost. Making green manure or compost yourself is still significantly more affordable.
  • 3) Not Self-Sufficient. If a self-sufficient garden is your goal, this product is of little use. Humic acid is a product you need to purchase from a store instead of making it yourself.
  • 4) Acidic Soil. You would use fulvic acid and not humic acid on highly acidic soils, as humic acid is less helpful on this soil type.

Can you use too much humic acid?

If you are worried about hurting your plants from adding too much humic acid, you don't need to worry. Research shows no adverse effects caused by applying a lot of humic acids.

But to get the maximum benefit from applying humic acid, you will want to spread it out, adding it to the soil over the whole season.

Since humic acid is not a fertilizer, you do not have to worry about creating toxic nutrient levels for your plants. But the primary disadvantage to over-applying is the cost of the product.

How to Increase Humic Acid in Soil

Unfortunately, to increase the humic acid in your soil, you will need to go out and buy the product and apply it to your soil.

Mixing Humic Acid With Fertilizer

Suppose you are going to mix humic acid with a fertilizer. In that case, it is best to mix with ammonium humate or ammonium nitro-humate.[4]

How to Use Humic Acid Fertilizer

Humic acid is available as a granular also a powder, and a liquid. You must remember humic acid is not a fertilizer directly providing nutrients to your crops. Instead, it enhances the nutrients already available in the soil, making them more available for uptake from your plants.

If your plot is low in nutrients, you will still have to apply fertilizer to get maximum results from your crops. But you will not have to use as much fertilizer compared to gardens without available humic acid.

how to use humic acid in the garden

how much humic acid to add to the soil
Granular Humic Acids

In granular form, add one to two pounds per every 100 square feet of soil. You can top-dress or mix it into the root zone and then water your plot well.

Home Garden

Adding granular humic acid to your plotted plants, you will use two tablespoons for every cubic foot of potting soil.

Liquid Humic Acids

You will need to dilute the solution with water for liquid humic acid before adding it to the ground.

Home Garden

For the home gardener, mix 1 Tablespoon of solution per gallon of water. You can apply every 6 to 8 weeks to get maximum benefits from it.

Large Plots

You will mix one to two quarts of the liquid solution with 30 gallons of water to apply to your soil for an acre. If you are using it for foliar applications, you will mix it with 6 gallons of water.

How often to use humic acid

when to use humic acid for plants

The granular version is usually a slow release that will stabilize humic acid inputs for the entire crop cycle.

Liquid humic acids should be added continually over the season for you to see the best results. On average, you should be adding liquid humic acid every 6 to 8 weeks of your growing season.


Humic acid is getting higher usage in agriculture and home gardens because of all its advantages.

It has a proven record of improving your soil characteristics and plant growth. However, while humic acid makes more nutrients in your soil available to plants, it does not directly add these nutrients as fertilizer does. It will take some time for you to see the benefits of adding it to your soil.

Humic acid can get applied in various methods, from being mixed into your soil as granular or mixed with water and added to your soil.

It is best to add the liquid form over the growing season continually than add a significant amount only once in the year.

Remember to pay attention to your garden any time you add a new product to it. Look at the health and growth of your plants over the season. Then you can determine if adding it is working for your plants.

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