Jan 222020
What Is Earthworm Castings – A Beginners Guide

What is earthworm castings? About 40% of the garbage generated by an average person is organic material. The organic material of the garbage is made up of all those remains that are created when you cook.

For example, the skin of the apple, the broccoli trunk, that poor part of the tomato, the tails of strawberries.

All this, if it is not separated from the rest of the garbage (the lint you sweep, non-recyclable containers, dirty papers) ends up in the landfill along with everything else.

There, it will decompose inappropriately, generating tons of methane, a more potent gas than carbon dioxide in terms of the greenhouse effect.

You may not know but when you add earthworm castings to the soil, they will improve the overall structure of the soil as well as provide all the essential nutrients and minerals to the plants.


Earthworm castings are very effective when it comes to repelling pests, which feed on plants. These pests are spider mites and aphids. In today’s article, I will tell you about the earthworm castings.

Earthworm castings are organic. They are a form of fertilizer, which is produced by earthworms. They are also called vermicast or simply vermicomposting.

The castings are earthworm waste. In other words, it is known as the earthworm poo. Earthworms can eat compost. The waste of these creatures creates organic and natural soil enricher.

When it comes to the shape of earthworm casting, experts say that they are like football-shaped particles, which enhance the aeration of soil as well as its drainage.

Another important thing you need to know about earthworm castings is that they can increase the retention of water in the soil, which is of great advantage to plants.

Earthworm casting is one of the simplest and most cost-effective solutions you can perform in your home.

Taking into account that the remains that are used to get the vermicomposting are organic remains, which account for more than 40% of the waste in the home.

With this, you will be able to fertilize and enrich the soils in a 100% ecological way, and at the same time, you will greatly reduce the organic waste.



Earthworm casting – the basics

Earthworm casting is a way to get a high-quality organic fertilizer, using organic waste generated by earthworms.

The decomposition of organic waste is generated by earthworms. For this, some conditions and a container that adapts to them are necessary.

It is not necessary for a large space. You can place it on a floor, balcony, terrace, patio, since the spaces required, are small.


Why perform earthworm casting at home garden?

As I have told before, it is a simple way to reduce waste and get a good quality fertilizer.

The reasons for performing domestic earthworm castings are the following:


  • You will reduce the organic remains that you send to landfills.
  • You will obtain an ideal organic fertilizer for garden plants.
  • To raise awareness and educate the population of the importance of the separation of different kinds of waste.
  • The earthworms will provide you with very high-quality humus, much better than any other type of fertilizer. Since it favors the growth and development of plant roots.


What are the optimal conditions earthworms need?

The most used worms to perform vermicomposting are the red worms to make earthworm castings. It is a red worm, with a somewhat flattened and yellowish tail.


They usually measure between 5 and 9 centimeters and 3 to 5mm thick. The optimal conditions that are needed are the following:

  • Humidity: needs constant humidity.
  • Absence of light: do not tolerate light. Therefore, the containers are prepared for it.
  • PH: do not hold a value of less than 4.5 of Ph. Acidic earth is not doing well.
  • Temperature: can withstand temperatures between 4 degrees and 30 degrees Celsius, but the ideal temperature is around 20 degrees Celsius.

From 3 months of age, the earthworms are in optimal conditions to reproduce. For each egg, laying 2 to 20 new worms can appear.

These small worms have a size of 1mm and are completely independent. At first, they are a white color, which after about 6 days becomes pink.

The worms can reproduce an average of 36 times a year and each earthworm can produce 0.3 grams of earthworm humus per day.



How to perform Vermicomposting?

The first thing to choose is the place to position it, you can put it on a terrace, patio, balcony and even inside the house.

If the site you choose is outside, you must take into account that it is in the shade and that you can protect it from frost.

You must acquire earthworm castings and a corresponding substrate so that the worms can live in it. Normally, it incorporates the substrate.

If you do not have the substrate, you can mix soil from the garden and some already fermented sheep and horse manure.

This land must be left extended for about 15 days to air before introducing it into the earthworms. When the soil changes to a dark brown color and does not generate any bad smell, it will be ready.


For placement in the earthworm castings, you will first put a newspaper sheet or cardboard, secondly the substrate, then the worms and, finally, a layer of organic waste from your home or garden.

The amount of waste will depend on the number of worms and the size of the castings. In a period of 7 to 15 days, the earthworms will consume the entire substrate. This will depend on the amount of food you provide.

When the substrate is consumed, it will be in small lumps, which will indicate that they have no food left. As you throw remains, earthworms will rise, since consumption will be made from the bottom up.

In turn, the earthworms will produce leachate, which is a liquid that is collected in the lower tray of the vermicomposter. This is a high quality liquid fertilizer for the plants.


What remains can you use?

You need adequate remains for an optimal result. It is very important to introduce suitable remains. The essential ingredients are Nitrogen and Carbon in an adequate proportion.

Nitrogen can be obtained from domestic remains such as carcasses and skins of fruits and vegetables. They have high nitrogen and their carbon-nitrogen ratio is very low.

It is convenient to cut them and cover them with paper so that flies do not come when you put them in the vermicomposter. You can also introduce grass remains but in small quantities.


Carbon or cellulose fiber is introduced to make the matter more spongy and loose. It allows better aeration, and after finishing the decomposition process leaves fiber thread that improves the earthworm humus.

You can provide paper and cardboard shells. The paper or cardboard shouldn’t be treated. To introduce them to the vermicomposter, they will be crushed and moistened. Others include eggshells, ground coffee, tea bags, hairs, etc.

Eggshells will give you calcium, but you must introduce it very crushed. Coffee and tea can be applied in small quantities.

On the other hand, you will apply the hairs without a problem since they degrade easily.

It is essential to add different contributions of carbon and nitrogen and introduce the remains as crushed as possible.

The remains that you should not introduce will be:

  • Large amounts of citrus remain onions, species or acidic foods.
  • Pine leaves
  • Animal bones, meat or fish.
  • Cheeses or dairy.
  • Butters or foods dressed with sauces and spices.
  • Glossy paper, since it is plasticized.
  • Poisonous or insecticidal plants.
  • Willow, noble, walnut or chestnut leaves.


Issues associated with earthworm castings

Bad smell

This is due to the decomposition of some remains by not being ingested by earthworms. It may be because they do not like it or that it is very large. You will remove the remains and add chopped paper or cardboard.

Excess flies

It is due to adding many fresh remains, mainly of fruits, uncovered with a paper. You must remove and open the lid of the vermicomposter to get the flies out and then cover the remains with paper.


This may indicate that moisture is missing in the vermicomposter. You can apply petroleum jelly to prevent access to the castings.

Going on vacation

The earthworms can withstand up to 4 weeks without feeding. Before you leave, you will provide plenty of food and try to keep the moisture with water bottles stuck face down in the substrate. You can also cover the vermicomposter with rags or wet cloth.

It is too dry

In the warmer months, you must control the humidity, with this, you also facilitate the creation of organic liquid fertilizer. In the months of autumn and winter, if the location of the vermicomposter is good, it is not necessary to water it.

Earthworm reduction

This can be the cause of one of the problems described above. It may also be due to some remains they do not like if so you must remove it from the vermicomposter and apply new fresh remains.


What does earthworm castings bring to plants?

It is the fertilizer with the best structure and the highest nutrient content. It is the best fertilizer you can get to apply to all types of plants, you can use it in the garden, home, field, organic garden, etc.

It is easily assimilated for plants and yields 5 times more than common manure. Once the castings are extracted, it is advisable to air them for 2 weeks.

It can be used as a cover fertilizer in the garden, to mix with the substrate for the preparation of seedlings, mix with the substrate of your pots, fertilize fruit or ornamental trees.



How to choose a vermicomposter?

Many containers are valid for vermicomposting.

You can buy them already pre-designed or make your own with materials that you have at home. What is true is that all vermicomposters must meet certain requirements:



Earthworms need oxygen to breathe, but beneficial microorganisms that help them break down your salad remains too. Every vermicomposter must have holes for air to enter.

If the air is scarce, start working on microorganisms that like this environment a lot (anaerobic). They will take care of breaking down the food, yes, but they will generate bad smells and make the worms sick.



You are trying to create an aerobic space (in other words: with oxygen) so that earthworms and microorganisms work in tandem.

Before a container of the same volume but different shape, the one with a larger surface is better for the composting process.

This must be with low height and elongated, as tray-shaped, instead of tall and narrow, like a garbage can. This allows more contact with the organic remains with the air.

Ideally, with stacked trays, you get more aeration and more composting in less space.

In each of the trays, there is compost in different stages, the earthworms can be moved from one to another as it suits them.





Advantages: breath more than plastic, which favors having an aerated medium.

Disadvantages: it deteriorates rapidly since it is recommended that the wood is not treated.




Advantages: resistant, light and durable.

Disadvantages: worse ventilation. It is necessary to make holes to favor the ventilation of the container.



Advantages: Breathes better than plastic and is more durable than wood.

Disadvantage: hard to find, heavy.


What to feed the earthworms?

This is the one million dollar question. Once you have them installed and happy in their new home, what remains can you throw them and which are not recommended?

Kitchen scraps, organic scraps, or traces of vegetables and fruits. But it’s time to get specific. Because the kitchen remains can contain from macaroni with sausage to coffee grounds or salad remains.

So that you can have the list of what organic remains your worms will enjoy and which is better to avoid, you can use the information presented in this blog post so that you know what to feed the earthworms.

If you have forgotten it, you can scroll up and know what is good for the earthworms and what you must avoid overcoming problems associated with earthworm castings.


What Is Earthworm Castings?: The Final Verdict!

Earthworm castings are definitely beneficial to your garden. There are different methods of keeping them and your process will affect the quality of the castings you have. This will have an effect on the quality of your plants too.

If you are interested in purchasing high-quality earthworm castings, please read my number one recommendation here. 


A Few Final Thoughts

If you ever need a helping hand or have any questions on this product or want to leave a comment or a review of your own, please do so in the space provided below.

I will be more than happy to answer them as best to my knowledge and would enjoy hearing from you.

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Reader Comments

  1. Hi Catherine. Thanks for the information. Regarding the “ant problem,” Is there something you’d recommend besides petroleum jelly to prevent access to the castings? It’s not something that is easy-to-find where I live.

  2. Never knew there was so much to learn about these little guys. I used to love worms as a kid and never really knew they were good for so much.
    This reminds me a little of Big Little Farm, all the vermicomposting and waste that is saved with composting is interesting to me. Have you seen that movie? It was super good, full of fun farming info.
    I live in an apartment and don’t have the place for a garden just now but would love to one day.

  3. This is very insightful. I bought a composting bin last year and wondered why it’s not working. Based on your post, I realized I did a lot of things wrong: I did not crush my eggshells, I did not cover the compost with papers thus a lot of fruit flies, not maintaining the humidity, etc. I will do your suggestions here and hopefully be able to successfully compost this year.

  4. I know that they do the job as I like to observe them in nature but I did not know that they are also available for sale. This is new information and it is very green. Do they multiply, too or do thy only reduce if they don’t go well with the remains?

    Thank you!

  5. I have never heard of earthworm casting. I’m always looking for new ways to “go green”. Thanks for this post. It has enough information, that I could start vermicomposting right away. Plus I now know why I should. I like that it doesn’t take up large spaces because I rent an apartment and have very limited square footage.

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