Vermicompost or worm compost is the fertilizer you can give to your plants. There are approximately 2700 species of earthworms and their job is to transform the soil into a plant-friendly environment. Earthworms are divided into three categories and each of them will help to build this plant-friendly environment in different ways:
- the anecic worms live deep below the ground surface and create permanent vertical burrows in the soil but cast on the surface. They would come on the surface and take dead leaves down in their burrows. They secrete a slimy substance that sticks into the walls of their burrows to hold them in place.
- the endogeic worms live under the ground surface and create horizontal burrows. Both endogeic and anecic worms help to make a better soil for the plants by aerating it, all the burrows they create transform the soil into a sponge absorbing air (oxygen) and water. The plants' roots also take advantage of these galleries to throw their roots down.
- endogeic worms live on the surface of the soil in the leaf litter layer. Contrarily to common belief, compost worms can and will also bury themselves in the soil and travel long distances underground to find a friendlier place. Endogeic worms are the family of worms that we use in vermicomposting, the compost worms. The most popular compost worms are: Eisenia Fetida/Andrei or Red Wigglers, Perionyx Excavatus or Blue Worms, Eisenia Hortensis or European Nightcrawlers and Eudrillus Eugeniae or African Nightcrawlers.
Both types of worms will consume organic matter and cast a rich fertilizer which feeds the plants. Anecic and endogeic worms, however, have a diet composed of carbon-rich material (dead and dry leaves) while epigeic worms can consume both. Worms don’t have teeth and need the help of organisms such as bacteria and fungi to help with the first step of decomposition of the organic matter. Each species of worms will also have a different bacteria species diversity inside their guts, that diversity will also change depending on the environment and diet. Bacteria and fungi will start breaking down the organic matter and the worms will suck in pieces of food that contains the microorganisms which will be digested. The nutrients released from the body of the microorganisms is ingested in part and the remaining goes out with the castings in the form of plant ready nutrients.
Before continuing, what is the difference between vermicompost and castings? Castings are worm poop. Vermicompost contains castings but also particles that have not gone they the worms’ digestive system. It would take many many passes for all the vermicompost to become purely castings but even then 100% castings is almost impossible to obtain unless you use some tweezers and a microscope to separate castings from other compost elements.
Vermicompost has a rather low NPK value, something from 0.5:0:0 to something like 2:4.5:9 depending on what food waste the compost worms have been fed on. Due to that low nutrient level, vermicompost is actually not considered fertilizer... but didn’t we say it’s the best fertilizer one can give to their plants? The value of vermicompost is not in its NPK value which is a commercial invention of the modern agriculture which sole purpose is to get more gardeners and farmers buy fertilizers especially chemical ones. Vermicompost is a soil amendment and its value is its contribution to what is called the soil food web.
Plants can only ingest nutrients that are water soluble and ingested through the leaves or via their roots. This is the reason why chemical fertilizers are so efficient, fast and attractive. Organic fertilizers on, on the other hand, take more time to show results, they need to be broken down first. This process is done by what is called nutrient cycling. Plants roots secrete sugars that feed bacteria and fungi. Plants lose their leaves, fruits and branches. Those are then broken down by bacteria and fungi that are in turn eaten by larger microorganisms such as nematodes or protozoa. The predators only absorb part of the nutrients from the bodies of their victims, the remaining are excreted into the environment around the plant roots that will absorb them.
So vermicompost is low in NPK, however, it contains a high diversity of beneficial microorganisms that once added to the garden will multiply and thrive if conditions are made suitable to them (the gardener adding mulch and keeping everything moist). The types of organisms present in the vermicompost will depend on the type and variety of food waste you have fed to the worms. Those microorganisms will then participate in the nutrient cycling in your soil and will transform mineral and organic matter into plant ready food. This is why in nature, plants don’t need humans to give them chemical fertilizers order to thrive.
On top of that, vermicompost also contains a good amount of plant growth hormones.
Good vermicompost makes happy plants:
In a next post, I will discuss how to use vermicompost.
Credits
- The image at the top has been generated with the Canva app using my own photo.
- Thank you Ben Jammin to share your point of view
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