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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.

Here’s why earthworm castings are considered good for your plants and lawn.

1. Seed Germination

The worm is an invertebrate that may accelarate 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.

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

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

3. Liquid Fertilizer

This is popularly referred to by gardeners as ‘worm casting tea’.

You can make it in much the same way as tea leaves by steeping castings into 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 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 near neutral, the castings can help balance acidic or alkaline pH levels in the soil and avoid leaf burn on plants.

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

The product produces a more porous friable soil quality that reduces surface crusting and allows air and moisture to penetrate. The excreted matter is also very permeable, helping to retain plenty of water in the ground.

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

8. Decrease in 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 clusters of minerals (‘aggregates’), the castings also help to avoid compaction of the soil as well as resisting erosion.

10. Plant Growth Hormone

Hormones have vital functions in plant life — enabling and speeding growth in saplings, shrubs, and trees or limiting production in drought.

Plants are unable to produce hormones, so they rely on nature’s way by drawing on provisions available in substances like worm casts.

The hormone-like effect of earthworm casts greatly influences the growth and development of plants [3].

11. High in Nutrients

Analyzed soils will show deposits of minerals and water. However, vermicast provides far more nutrients for plants and crops to thrive, whilst balancing the unhelpful minerals naturally contained in soils.

These invertebrate animals 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 micro-organisms. However, vermicomposting greatly increases the living organisms in the earth, enriching the soils with humus and feeding plant roots.

Vermicast is exceptionally high in nitrogen and phosphorus. It also provides the earth and plants with a life-giving dose of potassium.

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. This natural humus draws off harmful bacteria, toxins, and fungi from the soil, promoting better growing conditions.

The microorganisms in the soil benefit plants and crops by supplying vital nutrition and enabling supreme health and abundant growth.

13. Pest Prevention

Vermicast naturally repels pests 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 dehydrate and die. Many bugs and harmful pests that chew and suck on plants can be eliminated by the introduction of worm casts into the ground.

Commercial Supplies, Fertilizers, and Bins

The benefits of this liquid goodness in sustainable gardening and farming have led to commercially produced supplies of worms and vermicompost.

Many gardeners have turned to vermiculture, raising their own supplies of the invertebrates to benefit their garden, greenhouse, or indoor plants.

For compost, the ‘red wiggler’ worm, Eisenia fetida, is the correct type but those present in the soil will naturally continue to enrich plants and crops.

It is becoming fashionable for even town gardeners to have bins to produce nutrient-rich casts.


Digging and turning over the earth has long been a regular part of life 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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