Wonderful Worms: A Love Story For Your Soil

July 5, 2022 Bill Hageman

Worms Are Good For Soil

You probably know that worms are good for the soil. Charles Darwin wrote in his final book that worms “have played a more important part in the history of the world than most persons would at first suppose.” From recycling organic matter into nutrients, to increasing beneficial microorganisms in the soil, worms are essential to a healthy soil food web. But did you know that the best worms for composting are different from those that burrow in your garden?

Redworms for Composting

Redworms Eisenia foetida are the species of worms that are best for composting. These are different from nightcrawlers, which have a deeper burrowing habit that is not suitable for shallow worm boxes. Other species are also sometimes called redworms, but are not as efficient or adapted for life in a worm bin. Redworms live in decaying organic matter on the surface of the soil, and do not form permanent burrows like other worms. They eat dead organic matter (but not live plants or roots) and soil microorganisms, and digest these into castings that are full of beneficial microorganisms, nutrients, chitin, and plant growth hormones. They can digest up to half their body weight per day.

Redworms prefer a dark, moist environment that is free from pesticides. Although they can survive soil or bin temperatures from 32 to 84°F, they are happiest and most active around 68 to 70°F. It’s easy to start a worm bin! Learn how in our video and by reading “How to Start a Worm Bin.”

Earthworms for Gardening

While you could “plant” redworms in your garden, and will inevitably relocate some worms and eggs every time you use worm castings, redworms are not the best worm species to choose for populating your soil. Earthworms are better suited to the conditions that exist outside of a worm compost bin. There are hundreds of species of earthworms. These worms will burrow to depths of up to 6 feet, and will drag organic matter into their borrows to eat. Their burrows help aerate the soil, and the organic matter they incorporate into the soil helps improve its structure.

Earthworm castings are full of the same beneficial nutrients and microorganisms as redworm castings. Earthworms also excrete mucous from their skins, which additionally helps improve the soil. You can easily add earthworms to your soil with worms from Scarlet's Worm Farm. Give your new worms a good home, and encourage more worms to move in, by keeping the soil moist but not waterlogged, practicing no-till or low-till gardening, and not using harmful chemical fertilizers or pesticides in your garden.

Like your vegetables, worms prefer neutral or slightly acidic pH, low salt, with plenty of organic matter such as mulch, compost, and green manure. Learn more about earthworms from University of Nebraska - Extension.

FAQs About Wonderful Worms

Why are worms beneficial for soil health?

Worms help create healthier soil by breaking down organic matter, recycling nutrients, and improving soil structure. As they feed and move through the soil, earthworms create channels that improve aeration, water movement, and root growth. Their castings (worm manure) contain nutrients and beneficial microorganisms that support plant growth.

Are all worms good for composting?

No. The best worms for composting are specialized composting worms, such as red wigglers (Eisenia fetida). These worms naturally live in decomposing organic materials like leaf litter and compost, making them highly effective in worm bins. Garden earthworms, such as nightcrawlers, are better adapted for living in soil and creating deeper burrows rather than processing large amounts of compost in shallow bins.

What is the difference between red wigglers and earthworms?

Red wigglers (Eisenia fetida) and earthworms serve different purposes. Red wigglers are surface-dwelling worms commonly used for composting because they efficiently break down decomposing organic matter and produce nutrient-rich castings. Earthworms, such as nightcrawlers, live deeper in the soil, where they create tunnels that improve aeration, water movement, and soil structure. Both are beneficial, but they are adapted to different environments.

Can I add composting worms directly to my garden soil?

Generally, composting worms like red wigglers are not the best choice for improving garden soil because they are adapted to rich organic material near the soil surface and may not survive well in ordinary garden soil. For gardens, it is better to encourage native earthworms by adding organic matter such as compost or mulch, maintaining soil moisture, and avoiding harmful pesticides.

How can I attract and maintain healthy earthworm populations in my garden?

You can encourage earthworms by maintaining healthy soil conditions. Add organic matter such as compost and mulch, keep the soil moist but not waterlogged, minimize soil disturbance, and avoid practices that harm soil organisms, such as excessive pesticide use. A healthy soil environment provides the food and habitat earthworms need to thrive.

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2 comments

Make sure your worms are indigenous to your area. Red worms are more aggressive than earthworms and can take over displacing earthworms and soil ecology.

I split my worm bin a few weeks ago and just harvested about 10 pounds of red worm castings this morning with tons (well, pounds…) more to go. I asked my wife if she’s like to assist me separating the eggs/cocoons and the worms from the castings but she declined so it was all me. You should have seen my zucchini after I applied the worm poop. Wow!