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13 Benefits of Earthworm Castings

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13 Benefits of Earthworm Castings

The modest earthworm and its nutrient-rich castings (vermicast) have numerous benefits in producing healthy soil, plants, and crops [1].

Belonging to the phylum Annelida, earthworms were once considered lowly and insignificant. Today, with farmers and gardeners returning to organic methods of production, these creatures are now recognized for their immense importance.

Worm Casting Benefits

Below you’ll learn why worm cast is considered good for plants and your lawn.

1. Seed Germination

The worm is an invertebrate that may accelerate seed germination by means of its excrement or casts mixed into the soil. [2]

Besides, they help to aerate the soil and retain moisture for seeds to germinate and seedlings to thrive.

2. Lawn Conditioning

Lawns can dry out, and without fertilizer and sufficient moisture, the grass will quickly thin out and start to die.

The actions of earthworms allow the soil to become more porous and moisture-retaining, assisted by the water-filled castings.

The creatures digest nutrients from organic matter and excrete them into the earth, benefitting lawns as well as plants.

3. Organic Fertilizer

Worm castings are an organic fertilizer that is good for plants. You can also use it to make a natural liquid fertilizer or worm casting tea.

Make worm tea in much the same way as tea leaves by steeping castings into some water and distributing the liquid around plants/crops.

This is useful to encourage microbes and enrich plant roots, enhancing the size and vigor of indoor, outdoor, or greenhouse plants.

4. Organic Matter

Earthworms, through their digestive systems, break down ingested organic matter and excrete pure worm castings.

The liquid goodness then supplies a vast amount of nutrients to the soil, as well as food for other organisms.

5. Regulate Soil pH

Vermicast can achieve a stabilizing soil pH factor for the organic gardener. At a neutral pH of 7.0, the castings can help balance acidic or alkaline pH levels. Extreme pH levels prevent plants from absorbing nutrients from the soil.

6. Soil Aeration and Structure

The granular character of this organic product allows oxygen into the soil, essential to plant development.

The casts can also improve the condition of soils containing coarse-grained building material such as grit, gravel, sand, and the metallic elements of slag.

7. Maintain Soil Moisture

Worm cast produces a more porous friable soil quality that reduces surface crusting and allows air and moisture to penetrate. It also increases water retention in soil.

Additionally, earthworms can produce up to ten times their weight in casts, which greatly improves hydration to plants and crops.

8. Decrease Soil Erosion

The moisture-retaining and granular qualities of earthworm castings help to improve drainage and limit the damage from soil erosion.

9. Lessen Soil Compaction

By forming soil aggregates, the castings help to avoid compaction problems of the soil and improve its structure.

10. Plant Growth Hormone

Hormones have vital functions in plant life. The hormone-like effect of earthworm casts greatly influences the growth and development of plants [3].

11. High in Nutrients

Vermicast provides vital nutrients for plants and crops to thrive. It is exceptionally high in nitrogen, phosphorus, iron, and calcium. Earthworm casts also provide the soil and plants with a healthy dose of potassium and sulfur.

Moreover, earthworms are the real providers of good earth for sustainable gardening and farming. Through their digestive processes, they can break down large amounts of organic matter and excrete this in a form readily absorbed by plants.

Soils naturally contain microorganisms. However, vermicomposting greatly increases the number of living organisms in the soil. It also enriches the soil with earthworm humus which is good for plant roots.

12. Microbes

One of the principal benefits of worm composting is the increased microbial activity in the soil. The nutrients released from the casts assists in the growth of plant life and microorganisms. It also gives protection against harmful bacteria and disease.

Plants susceptible to rot and wilt diseases are more resistant and also stronger from the increased nitrogen in the soil promoted by the worm manure. The microorganisms in the soil benefit plants and crops by supplying vital nutrition and enabling supreme health and abundant growth.

13. Pest Prevention

Worm castings naturally repel pests such as whiteflies that damage plants and crops.

Along with hormones and good bacteria, the tea contains enzymes. One of these enzymes, chitinase, reacts with the exoskeletons of pests to dissolve the essential element, chitin.

Without this covering, the pests get dehydrated and die. Therefore, many bugs and harmful pests that chew and suck on plants can be eliminated by the introduction of worm casts into the soil.

How to Make Worm Castings

To make organic worm castings, obtain a container or worm bin that is suitable for the process. The bin must not be too deep (10 inches deep is ideal) and there should be drainage holes at the bottom.

Put in a layer of sand and moistened newspaper strips at the bottom. Next, add some dried leaves, compost, manure, and then top it off with more moist newspaper strips and soil.

It’s now time to add the worms and food for them. Throw in some garden scraps and/or kitchen scraps. Now leave them alone for a few months.

However, not every worm will survive in composting bins. Lumbricus rubellus (red earthworm), Eisenia fetida (red wigglers), and Eisenia hortensis (European Nightcrawler) are species that are suitable for vermicomposting. Moreover, you can purchase them online here and here.

Alternatively, buy commercially-produced worm casting compost if the DIY process is too much.

Harvesting Worm castings

After a few months have passed, lay out some old newspapers or a plastic sheet and empty out the contents of your worm bin.

Next, collect the worms and add them to a new vermicompost bin. Finally, use the castings on your plants. That leftover is what is called worm casting fertilizer.


One of the disadvantages of worm castings is that it takes time to create. Three months is the minimum and it may take up to a year before you can harvest a good amount.

Another one is the cost. If you choose to buy earthworm fertilizer instead of making your own, you will find that it is more expensive than regular fertilizers.


Digging and turning over the soil has long been a regular part of the process for all who love their gardens. Seeing earthworms come up with the soil is a normal sight but in recent years science has revealed the true benefits of the humble creature.

Image via commons.wikimedia.org

Sasha Brown

Blogger and lover of all things natural.

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