Earthworm Castings in Growing Marijuana

One of the best ways to ensure a bountiful marijuana harvest is to use earthworm castings on the soil. This natural material is the by-product of the food digested by the worms. As such, it is purely organic and extremely rich in both the main nutrients and trace minerals that are essential to the plants.

While many growers commonly associate composting with hard work, using this method is relatively easy. Basically, all we need is a good environment for the worms and plenty of food supply to work their magic. Once we apply it to our crop, expect to see it grow healthier and produce richer buds.

To get started in using worm castings, it is best to know the basics about it. Hence, this article will cover its benefits, production, and usage. Because of its tremendous positive effects on the plants, learning about it can be extremely valuable to cannabis growers.

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What We Need to Know About Worm Castings

Again, the best way to supercharge the soil is to use worm castings. But how do we get started with this method? For interested growers, this section will provide all the necessary information to start using it effectively in the garden. But first, let’s take a quick look at its composition and benefits.

1. What is it?

As mentioned, worm castings are the excrements of worms from digesting various food scraps. Somehow, through their digestion process, they produce this material that is loaded with rich nutrients for the soil.

1.1 Worm Castings vs Vermicomposts

WormCasting in Growing
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Worm castings slightly differ with vermicomposts when it comes to composition. While the former is made purely of worm feces, the latter is a mix of the castings and other materials in the compost. Both have the same basic ingredient and are often combined with each other. Thus, many growers use these terms interchangeably.

1.2 What kind of worms can we use?

Red Worms
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There are specific earthworms that growers use for this purpose. The two main types are the Lubricus rubellis and the Eisenia foetida which are also the ones we use as fish baits. Casually, they are known as the red worms, red wrigglers, tiger worms, and the manure worms.

2. What are its benefits?

Aside from being totally chemical-free and inexpensive, using worm castings can make huge improvements to the garden. In addition, they are readily available and are easy to make. So, what more do we need? To truly appreciate their magic, let’s examine how they are beneficial to the crop.

2.1 Aerate the Soil

Aerate the Soil
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While most gardeners keep their worms in a container, some are more practical and just let them loose in the garden. This allows the worms to perform their most obvious functions which is to tunnel through the soil and introduce oxygen in the process. As a result, the roots get enough space to absorb more water and nutrients.

2.2 Environment-friendly

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Aside from being nature’s decomposers, worms also help households reduce their waste by recycling their kitchen scraps. This significantly reduces landfills while enriching the soil and produce bountiful harvests. Add to that, using castings eliminates the need to use harmful chemicals in the garden.

2.3 Get Rid of Harmful Microorganisms

Get Rid of Harmful Microorganisms
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Worm castings release substances in the humus that eliminates toxic fungi and bacteria. In effect, they fight off diseases that could possibly weaken the plants and affect our yield. Moreover, they also introduce good microorganisms that help make the soil richer and the plants healthier.

2.4 Make the Soil More Absorbent

Make the Soil More Absorbent
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The castings can make the soil absorb moisture more easily. As a result, the soil gets all the water that it needs, keeping the plants well-hydrated and at no risk from completely drying out.

2.5 Stabilize the pH of the Soil

Stabilize the pH of the Soil
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The soil needs to have a balanced pH to absorb the essential minerals. When we apply the worm castings, this immediately corrects any imbalances in the pH level. Hence, for many growers, this is the best remedy and preventive measure for nutrient problems.

2.6 Teeming with Nutrients

Teeming with Nutrients
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Compared to the ordinary potting mix, castings have ten times more nutrients. In fact, they contain over 60 micronutrients and other essential elements including nitrogen, phosphates, and calcium. Even better is that unlike commercial fertilizers, they are released slowly in the soil, preventing any nutrient burn or mineral buildup.

2.7 Remove Toxins in the Soil

Remove Toxins in the Soil
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Sometimes, there are heavy metals and other toxic matter in the soil. Impressively, worm castings remove these dangerous wastes, leaving the soil safe and suitable for the plants to grow in. This is especially useful when growing marijuana in reclaimed landfills or other contaminated areas.

2.8 Repel Pests

Repel Pests
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Aside from enriching the quality of the soil, worm castings also protect the plants from pest damage. Studies found that applying them around the plant promotes the release of chemicals that are offensive to insects. In effect, we control pest problems without resorting to chemicals.

3. How do we make it?

While some growers prefer to buy the castings from a local garden supply center, others like to make their own. The great thing about this method is that we can practice it anywhere. Whether at home or in the office, anyone can start making worm castings in three easy steps with the help of a few simple things.

Step 1: Select a Container

Select a Container
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Before getting the worms, prepare a suitably-sized bin for the desired amount of castings. Nowadays, there are so many types of commercial worm containers that are available online. They are designed for home use, so they are very easy to manage.

Step 2: Obtain Earthworms

Obtain Earthworms
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Now that we have a container, it’s time to get the worms. Most growers prefer to acquire them the easy way and purchase them at the local garden store or online. Others like to comb the soil for red wrigglers themselves. But remember that we need at least a thousand of worms if we want to produce a decent amount of castings.

Step 3: Provide the Basic Needs

Provide the Basic Needs
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Worms need a bedding which we can easily provide by placing shredded newspapers or cardboard for them to tunnel in. Since worms need a bit of moisture, make sure to have extra beddings to absorb it.

Provide the Basic Needs

To create an environment for them to thrive, we also need to add sawdust, cornmeal, straw, or coco coir. Now for their food, give them kitchen scraps such as fruit and vegetable peelings, coffee grounds, tea bags, grains, and bread.

Provide the Basic Needs

Basically, they tend to produce more nutritious castings if they get a well-balanced diet. But avoid giving them meat or dairy which often attracts bad bacteria. Also, make sure they don’t run out of fresh food to consume. A good rule of thumb is to provide a pound of scraps to a pound of worms.

Step 4: Harvest the Castings

Harvest the Castings
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Depending on the size of the container and the number of worms, we can harvest the castings every two months.

4. How do we use it?

How do we use it
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We can use the castings right away or store it for the next growing season. But don’t be disappointed if we extract only a handful from the bin. In favorable conditions, the worms multiply rapidly and will make more castings if we provide them enough food.

To use, simply mix the castings with the compost or use it as a side dressing for an indoor plant. We can also use the “worm tea” by watering it to plants that need a boost. Whichever way we use them, we can expect to see satisfying results.

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Final Thoughts on Using Worm Castings

There is nothing more natural than using worms to enhance the quality of the soil. Since they are nature’s fertilizers, they offer the most abundant nutrients with the least harm to the environment. Hence, growers who practice this method get the most nourishing soil and the healthiest plants.

To get started with worm castings, learn everything about it first. While the process comes naturally, we need the knowledge and skills to sustain it. By doing so, we get decent amounts of the castings that will boost our chances of getting a successful harvest every time.

Learn more about increasing your yields at harvest time with my free mini harvesting guide.

FAQs About Worm Castings on Marijuana Plants

Are worm castings also ideal for seedlings?

Yes, they can be used for seedlings as worm castings will not burn the roots of your plants, unlike synthetic fertilizers. They also have microorganisms that nourish your soil (including potting soil) and help prevent other plant diseases, in addition to providing natural resistance to most pests.

Is using worm castings better than composting?

Because worm castings have sufficient amount of nutrients and help with plant hydration and aeration, they’re ideal for smaller gardens. However, worm castings can be more expensive than compost and other soil additives.

How often should worm castings be used?

It is recommended to apply a 1/8- to 1/4-inch layer of earthworm castings between each layer of compost materials. Then, every two to three months, you can supplement your bin with fresh castings.

Want to be an expert cannabis grower? You only need practice and learning. Let my blog help you get started.

Have you ever used worm castings on the soil of your marijuana plants? Please share your experience or leave questions in the comments!

Happy growing!


Avatar for Robert Bergman

Robert Bergman

Robert Bergman is an Amsterdam-based marijuana grow expert who has years of experience from small grows to massive operations. His passion for growing led him to develop his own Gold Leaf strain. Now, Robert is dedicated to sharing his knowledge with the world.... [Read full bio]


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