Are Worm Castings Considered A Fertilizer?

You may have wondered if worm castings are considered to be a fertilizer?


To put it bluntly, YES!   


We’re about to explore why earthworm castings can be considered one of nature’s most complete, all-natural, organic fertilizers. 


But first, let’s talk about the actual term “fertilizer”.    


If you look up the definition, you’ll probably find something along the lines of:


fer·ti·liz·er, noun

a chemical or natural substance added to soil or land to increase its fertility.


So, by definition, if something increases the “fertility” (aka, the ability for plants to germinate and grow) in soil or land, then it can safely be considered to be a “fertilizer”. 


LEGAL Disclaimer: This article is NOT LEGAL ADVICE.  It should be noted that many state and local governments provide exceptions in their laws regarding animal manures and similar products (including worm castings). Those products are often NOT considered fertilizers for purposes of fees, tariffs, taxation and licensing.  (*Please check your local laws to be sure, especially if your business is involved.)  


But for the purposes of the backyard gardener or hobby farmer: Yes! Worm castings can be considered one of the world’s finest, all-natural fertilizers and soil conditioners.


Ø  Okay, how do worm castings increase “fertility” in soil and land?


In order to truly understand how worm castings increase the fertility of your lawns, gardens and fields, you should first consider a couple of the amazing benefits of worm castings.


Let’s review them briefly, while discussing how each benefit adds to soil fertility:


Castings Build Soil Structure 

Worm Castings enhance the condition of your soil due to their extremely high humus content.  Humus, the organic matter at the core of each individual casting, acts like a tiny sponge in the soil.  It holds and retains moisture, nutrients, minerals and beneficial microbes to produce an amazing all-in-one soil builder! 

In addition to providing their own powerhouse source of plant nutrients, worm castings also work to aid in the retention of OTHER minerals, elements and fertilizers in the soil.  They amplify all of your other soil building efforts, supplements and amendments while still always being able to serve as a standalone organic fertilizer. 

Soil aeration is a major pain point for many gardeners and farmers alike. By incorporating worm castings into your soil, you can improve soil’s ability to allow water and oxygen to more freely flow throughout the root zone.  At the same time that the castings are creating space for air, water and roots to move through the soil, they’re holding on to vital nutrients and minerals that will eventually be needed by the plants! 


Faster Germination Times and Better Root Health

Earthworms produce castings that are encased in a layer of digestive enzymes from the worm’s gut.  In nature, these enzymes actually aid plants during the germination and root-growth phases. Plants are able to get a strong foothold and establish a good network of thick root fibers that will serve to gather nutrients, elements and minerals later on in the plant’s life cycle.  Real world scientific studies indicate that plants grown in soil amended with worm castings have significantly faster germination time and vastly improved root strength leading to happier, healthier plants! 



Worm castings are full of life!  Just like there are live organisms in dry yeast, there are live microorganisms in worm castings.  These bacteria, fungi, protozoa and beneficial nematodes all work together to help your plant thrive throughout its life cycle.  Microbes also help to solubilize nutrients and minerals in the surrounding soil for better plant uptake. 

When soil is lacking in microbial activity, it’s like a car engine with no gas or oil -- it’s just not going to work. 

Soil microbes, through their natural day-to-day routine of scavenging for food, eating and of course, pooping, help create a perfect environment for plant growth.  One of the ways they do this is by solubilizing minerals and nutrients. In other words, they change bound nutrients, elements and minerals (which are trapped within soil particles) into plant available form! This process is as natural as birds flying overhead or clouds rolling over the landscape. 

But far too often, home gardeners and farmers inadvertently KILL these wonderful little microbes by using harmful chemical herbicides and pesticides.  Sure, these products kill off the unwanted weeds or pests, but in doing so, they also kill off the beneficial bacteria and microorganisms as well. 

As a result, the soil’s “engine” is effectively shut down.  Because the microbes are no longer alive and working to perform the crucial task of solubilizing the nutrients from the surrounding soil particles, plant performance begins to suffer.  The farmer or gardener is then forced to add additional nutrients and supplements (often synthetic or chemical in nature) in an attempt to recover plant performance. They see a temporary boost in their plants and think, “Ok, this works!  Products A + B to handle weeds and bugs. Products C + D to provide nutrition!”

A vicious, repeating cycle has now begun where the grower is dependent on four different products to get the results they need.  Many are unaware that they could easily get many of the same benefits as the most expensive pesticides and fertilizers through an all-natural, organic alternative – worm castings!

Worm castings introduce beneficial microbes back into the soil which then, in turn, go on to colonize the surrounding soil and root zones.  This of course attracts other earthworms and microbial soil life to the area which then serves to aid and strengthen the soil fertility even further.


Castings Will Not Burn Plants

We've all heard the horror stories of some unfortunate soul who over-fertilized their plants and "burned" them.  This happens due to a sudden nitrogen excess in the soil and if you make this critical mistake, you can kill plants overnight.  

Completely -- with zero chance of saving them.

Fortunately, worm castings just do not have this problem.  Going back to the high humus content, worm castings don't overload your plants with excess minerals and nutrients.  Instead, they hold and then slow-release the necessary nutrients as needed by the plant. Your soil fertility will surely benefit from the addition of worm castings as part of your growing regimen.


Packed with 60 Trace Minerals and Nutrients

Worm castings are high in trace amounts of over 60 minerals and nutrients content.  The worms at Dr. Verm’s are fed a diverse vegan menu high in essential minerals and nutrients from organic, non-GMO plant material.  These minerals and nutrients are naturally transferred by the worm into its castings, and finally into your soil after the castings are added.   Flower blossoms are usually much larger, more bountiful and more colorful. Since plants are provided with nearly all of their nutritional needs by either by the added castings or by the work of the resulting microbial populations, the nutrient density of produce tends to be MUCH higher and fruits and vegetables typically have MUCH better taste profiles! 


In closing, it’s pretty clear that worm castings can (and probably should) be classified as a fantastic all-natural fertilizer.  But their benefits go above and beyond simply fertilizing the soil. 


They also:

  • Act as a defense against drought by aiding in water retention.

  • Help in fighting off both airborne and soil-borne diseases.

  • Aid in the defense against insects and other pests. 


If you’re searching for an all-in-one, all-natural, organic fertilizer AND soil builder, you can’t go wrong with premium worm castings.

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