What Does Humic Acid Do For Grass? + Why It Makes Your Lawn Better

What Does Humic Acid Do For Grass

One of the most popular trends in lawn care in recent years is an adoption of the philosophy that we should be feeding the soil in our lawns just as much (if not more) than we feed the grass itself.

Lawn fertilizers will provide nutrients to the root systems of grass plants growing in the lawn but when the soil itself is healthy and alive with an abundance of beneficial microbes then the grass in our lawns will be healthier… even when we dial back the use of fertilizers, herbicides, and fungicides.

Humic acid is one of the simplest (and best) options we have as “yard owners” for improving the soil structure in our lawns and the life that the soil supports.

Humic acid does not provide nutrients to the grass but it does allow nutrients that are in or applied to the soil to be used by the grass more efficiently. It is a carbon-based product that takes millions of years to form and when it is added to the soil beneficial microbes and mycorrhizal fungi can thrive which benefits the grass in many complex ways.

In my lawn I apply a number of different products that all contain Humic acids such as my liquid aeration products, my root grow stimulants, as well as my favorite stand alone Humic acid product, N-EXT Humic12 by Green County Fertilizer.

Before we get deeper into how Humic acids work and let’s first explore some of the most obvious ways that Humic acid benefits the grass in your lawn before we touch on some of the less obvious reasons to apply Humic acid to your lawn regularly.

Here is a video I produced on this topic that I suggest you watch before reading further down the page:

A Complete Guide To Applying Humic Acid to Your Lawn

If you’ve been tending to your lawn for any amount of time using the same old standard products which are sold in bog-box stores everywhere you might find that your results will be capped no matter how much fertilizers you apply or weed killers you buy. You may even regularly find bare spots in a lawn littered with patchy with weeds.

Your lawn may stay like this from season to season whether or not you continue fertilizing, top-dressing, over-seeding, aerating, or dethatching. In most cases the soil structure is the problem not the nutrients added to the lawn and liquid carbon-based humic acid can be part of the solution as it doesn’t add any extra nutrients to the grass bur rather improves the soil so that your lawn can actually improve.

You have to have a firm foundation to build something great after all.

Unfortunately you can’t always tell good soil structure by simply grabbing a handful and feeling the texture with your fingers; there are a lot of factors to check, some physical, biological, and chemical.

The carbon in your soil is microscopic and it can provide places for nutrients and microbes to live resulting in better moisture retention, nutrient availability, and biological activity. Nutrient leeching can also be minimized by improved soil structure.

When you feed the microbial life in the soil with Humic and Fulvic acids you create an aerobic environment that allows for biological and chemical reactions that only occur when oxygen, water, and carbon dioxide is present and available.

So, obviously a discussion of Humic acid has to look at the science behind how it is formed, how it is applied, and how it works.

What is Humic Acid & How Is It Applied

Humic acid (and the Fulvic acids that accompany it) is extracted primarily from Leonardite, a rock that is a geological precursor to coal. Organic debris that fully decayed millions of years ago slowly transform into coal but before the transformation is complete Leonardite contains these molecular chains that can be extracted. Carbon content is still extremely high and the molecular chains in the Humic acid varies a bit.

Humic acid molecules are larger than Fulvic acid molecules so it’s believed that the Fulvic acids enter the root system of plants ushering nutrients in with them while the Humic molecules remain in the soil improving it’s biological health.

Whether you have clay or sandy soil, there’s an effortless way to fix your soil condition, and the best part: it’s environmentally friendly.

Here is a more substantial video I produced explaining how exactly Humic acid is formed and produced for lawn and garden enthusiasts.

In my lawn I use liquid dethatching products which are meant to feed microbial life so that it will compost down thatch layers in lawn settings. Humic acid is a big part of that process. You can read more about dethatching on this page.

I also use liquid aeration products to both loosen my soil and allow for more substantial root systems in my lawn system. These products all use Humic acids to help accomplish the task at hand.

You can see a lot of the products and recommend on this page.

In fact many root development strategies and stimulus include Cytokinins found in sea kelp extract and Humic acids found in Leonardite because these two “ingredients” help plant systems starting at the root work more efficiently.

You can see more about my personal root development philosophy on this page.

Humic Acid vs Humus: Are They Different?

Humus is a black substance that increases the nutrient holding capacity of any soil. It helps plant roots to retain water and nutrients.

In the simplest term, humus is formed by microbial activities on dead plants and animals. This causes them to decay, and the decomposed organic matter becomes organic fertilizers for the soil.

The older humus gets the less nutrients it has in it which is why compost is the beginning stages and Leonardite is one of the last stages.

Humic substances, frequently known as humus, are made up of humic acid, fulvic acid, and humin. When Humic acid is extracted from Lenardite humin is left over.

I’ll spare you the science right now because this post is all about what humic acid does for your lawn and how you can apply it.

What Humic Acid Does To Lawns

As previously mentioned Humic acid does a few different things in the lawn that can be generally sorted under a few buckets. It affects things like soil structure, biological life, soil nutrient holding capacity, and nutrient availability.

Humic acid is a dark brown savior, a highly soluble in substance that contains amino acids and other chelating agents. So, when applied to the soil, humic products unlock nutrients and trace elements in your soil and helps your soil absorb the best of any fertilizer you add to your soil… if you choose to add any into the mix.

Let’s list all of the primary benefits of adding humic acid to your fertilization routine.

Top 10 Benefits of Adding Humic Acid To Your Lawn

  1. Humic acid improves your soil condition, so it retains more water and nutrients
  2. Humic acid stimulates root growth and promotes plant cell division
  3. It increases healthy carbon in the soil that supports plant growth
  4. It helps to aerate the soil while improving bioactivity
  5. Humic acid also adds to the physical characteristics of the soil (structure, color, and consistency)
  6. Improves germination rates of seed during over-seeding
  7. It increases photosynthesis and chlorophyll concentrations in living plants
  8. It helps in scavenge toxic pollutants or instead, to detoxifies the soil
  9. It improves the growth of beneficial micro-organisms
  10. The Fulvic acids in Humic acid products aid in nutrient uptake from root systems

Again, many premium bio-stimulants these days include humic acid as an active ingredient. You can see my recommended products for lawn care here.

How to Use Humic Acid In The Lawn

There is no specific volume amount of Humic your soil will need and most professionals will tell you you can’t over apply it either.

Spoon feeding Humic acid is usually considered to be most beneficial to lawns. By this I mean applying a little bit at a time many times over a season should be better than apply a lot only once or twice in a season.

Any amount should be okay if you mix it with water. But depending on the concentration of the product you’re using you will be able to spread it better if you dilute liquid Humic acid in a lot of water instead of a little.

If you choose to apply granual Humic acid then you should expect to have to water it in heavily and then wait a couple of days to weeks for it to start working. Soil temperature and moisture levels have to break down the granuals before it starts affecting the soil and root system of your lawn.

► Quick Tip: Humic acid performs best when you apply it along with regular lawn fertilizers or in the early part of Spring as lawns are emerging from winter dormancy.

If you choose to go with a water soluble Humic Acid product (which I don’t prefer) the first step will be to scoop it into a big bucket for mixing and follow label rates on the low end to start a spoon-feeding plan.

After scooping the acid into the water, pour a generous amount of water and mix. You can start with a gallon of water or two. Then mix thoroughly for about two minutes before putting it into a movie sprayer to spray all over your lawn.

The biggest benefits of mixing Humic acid into water yourself is that these powders are usually cheaper and you can easily refine the dilution to your liking. I prefer the Humic12 product however because to solution is smooth and I don’t ever get clumping or clogged spray nozzles plus I still dilute further to my own liking.

What is The Best Time To Apply Humic Acid?

On a lighter note, I always say that unless you want to work on your tan line the best time to apply your humic acid to your lawn is the cool of the day, morning or evening.

More seriously though you’ll be able to get Humic acid down pretty much any time of the day just fine if you are spreading dry humic granuals. You don’t need to water them in right away; for that you can wait for rain or wait for the irrigation system to turn on in the wee hours of the morning later on to water it in.

For liquid versions or dissolved mixtures it’s usually best to apply in the early morning or late afternoon/evening to limit your risk for damaging grass blades in the hottest parts of the day. With humic only products this risk is very low however.

In terms of time of year for application Humic acids can be applied at any part of the year, any season. Because they work to build up the health in the soil they will work even when your lawn is dormant.

I would avoid applying to frozen soil and you will get full benefits when applied to non-dormant grasses but a stand-alone version of Humic acid will slowly work to build up the carbon components in your soil and feed microbial life once those microbes wake up from winter.

It is also an excellent practice to apply Humic acid immediately after core aeration of a lawn if you ever get that done. A freshly aerated lawn allows for product to get deeper into the soil faster than at any other time. This is part of the top-dressing strategy I explain in my Lawn Root Development course which you can read more about here.

Can You Apply Too Much Humic Acid To A Lawn?

Two common reasons people reduce application rates of Humic acid is the fear of applying too much at once and the cost of applying more than is necessary. Some people worry that over-application will harm the lawn.

The thing is however that you can’t really apply too much Humic acid to the soil at once but if you apply a lot at once instead of spreading it out over a full season you aren’t likely to get all the benefits of the product.

Research shows that there aren’t any adverse effects caused by applying a lot of humic acid to a lawn but spreading it out always results in better results because grass plants can only uptake and use so many nutrients at a time.

In terms of the carbon influx in your soil and the bio-stimulant effects on the critters living in your soil consensus is that the more Humic added the better.

Categorically I’d say that no amount of Humic acid, the concentration of Humic acid, or the application rate of the acid will hurt your lawn. Instead, plants grow better and look healthier on the soil with more Humic acid. Your only main limitation is the amount of money you are comfortable spending on lawn applications.

Now I’m not going to suggest you put down enormous amounts of this stuff on your lawn; it may not damage it but applying frequently at ridiculously high application rates is probably unnecessary.

I suggest you take a look at my recommended product page to see which bio-stimulant products I use and recommend because most of them include Humic acid on the list and they work synergistically in most cases to benefit lawns.

NPK fertilization is a necessary component of DIY lawn care but don’t rely on it by itself. By implementing a broad scope strategy you can have a healthier lawn built upon healthier and more fertile soil.