Worms for the garden

I’ll bet you think that the earthworm is only good for fishbait. Well, think again. The earthworm is one of nature’s top “soil scientists.” The earthworm is responsible for a lot of the things that help make our soil good enough to grow healthy plants and provide us food.

Worms help to increase the amount of air and water that gets into the soil. They break down organic matter, like leaves and grass into things that plants can use. When they eat, they leave behind castings that are a very valuable type of fertilizer.

Earthworms are like free farm help. They help to “turn” the soil—bringing down organic matter from the top and mixing it with the soil below. Another interesting job that the worm has is that of making fertilizer. If there are 500,000 worms living in an acre of soil, they could make 50 tons of castings. That’s like lining up 100,000 one pound coffee cans filled with castings. These same 500,000 worms burrowing into an acre of soil can create a drainage system equal to 2,000 feet of 6-inch pipe. Pretty amazing for just a little old worm, don’t you think?

Having worms around in your garden is a real good sign that you have a healthy soil.

Earthworms’ role in the ecosystem

Charles Darwin is well known for his work on natural selection. He published widely on topics ranging from barnacles to geology to plants. He travelled the world and saw many unusual animals. Near the end of his life in 1881, he wrote in The Formation of Vegetable Mould,

It may be doubted whether there are many other animals which have played so important a part in the history of the world, as have these lowly organised creatures.

Charles Darwin

Darwin, of course, was referring to earthworms.

Earthworms may lack the charm or excitement of more familiar animals, but their contribution to our world is significant. These ‘lowly creatures’ play a vital part within the natural soil ecosystem. They are also valued for their contribution to ecosystem services – ecosystem functions that are of direct benefit to humans through their action on soil processes.

Earthworm benefits to ecosystems

Earthworms are sometimes known as ‘ecosystem engineers’ because they significantly modify the physical, chemical and biological properties of the soil profile. These modifications can influence the habitat and activities of other organisms within the soil ecosystem.

Earthworms influence (and benefit) the soil ecosystem in a number of ways:

  • Recycling organic material: Earthworms, along with bacteria and fungi, decompose organic material. Most people know about earthworms and compost, but earthworms do the same in pasture soils, decomposing dung and plant litter and processing 2–20 tonnes of organic matter per hectare each year, and recycling leaf litter under orchards and in other forested areas.
  • Increasing nutrient availability: This happens in two ways: by incorporating organic materials into the soil and by unlocking the nutrients held within dead organisms and plant matter. Nutrients like phosphorus and nitrogen become more readily available to plants after digestion by earthworms and being excreted in earthworm casts. Scientists have measured up to five fold increases in nitrogen availability in earthworm casts compared to undigested soil. Earthworms also take nutrients down through the soil profile, bringing them into closer contact with plant roots.
  • Improving soil structure: Earthworm burrows alter the physical structure of the soil. They open up small spaces, known as pores, within the soil. When earthworms are introduced to soils devoid of them, their burrowing can lead to increases in water infiltration rates of up to 10 times the original amount. This brings water and soluble nutrients down to plant roots. Burrowing also improves soil aeration (important for both plants and other organisms living in the soil) and enhances plant root penetration.
  • Providing food for predators: Earthworms, like all creatures, are part of food webs. Birds are well known predators, but native earthworms are also food for endangered and endemic land snails.

Earthworm benefits to humans

New Zealand scientists have had a unique opportunity as far as earthworm research is concerned. Once land was cleared for production agriculture, native earthworms quickly disappeared. Unless non-native species of the lumbricid family were introduced to the area, earthworms were absent for periods of time. Scientists have been able to investigate the effects of introducing earthworms to pastoral lands and quantify the benefits they provide.

Earthworms provide these ecosystem services to humans:

  • Increasing pastoral productivity: Once lumbricid earthworms become established, pastoral productivity increases by 25–30%. This is equivalent to 2.5 stock units per hectare. Earthworms remove the surface thatch material that can block water from entering the soil, as the thatch can cause it (and soluble nutrients) to run off.
  • Facilitating and accelerating mine restoration: By increasing soil fertility, recycling waste products and providing food resources for predators, earthworms help to restore functioning ecosystems both above and below the ground.

Trish Fraser, a soil scientist and earthworm expert says, “The next time you see an earthworm struggling on the footpath, perhaps you will be kind to our little underground ally. Indeed, perhaps you will also think about the rest of the large army of earthworms working hard for us below the ground. Maybe then the important role that this underground army plays in our lives will be forgotten no more.”

Nature of science

Humans are part of the Earth’s ecosystems. Our activities, such as clearing native forests for agriculture or introducing lumbricid earthworms, alter the balance in ecosystems.

Useful link

The giant, native Powelliphanta snails are carnivorous and eat earthworms that they slurp like spaghetti! View a video of their life cycle on Te Ara – The Encyclopaedia of New Zealand.

Are earthworms good for your garden? Many gardeners believe that earthworms are a benefit while those who garden in a very heavy clay soil would be quick to disagree.

There are many studies that show earthworm activity helps to form better soil aggregates which in turn will help soil to support better plant growth with less compaction and erosion. Just compare the difference earthworms can make in the production of topsoil. It might take 500 to 1,000 years for nature to produce topsoil in the absence of a adequate soil animal population. However, under favourable conditions earthworms can shorten this process to a little as five years. This is because of the ability for earthworms to mix, till and build topsoil as they go about their daily business of burrowing through the earth.

article continues below

Trending Stories

  • Uranium City: Saskatchewan’s last frontier

The most “common” species of earthworm we would encounter is Lumbricus terrestris and it is amazing to learn the lowly earthworm has not been an inhabitant of North America forever. In fact, only after the last glaciations period have earthworms been introduced to our lands.

Beneath lawns, earthworms are amazing. They help to improve water infiltration, which leads to a deeper rooted lawn. This of course helps lawns to better withstand periods of drought. Earthworms help to increase soil organic matter by bringing deeper soil closer to the surface. This helps to decompose leaf litter (which reduces thatch) and amends the soil without any effort on behalf of the gardener. The only drawback is sometimes earthworm activity can leave lumps, which are distressful to some lawn fanciers.

If you can see these lumps from earthworms then you are very likely mowing your lawn a bit short. Try adjusting your mower height to ensure your lawn has lots of leaf tissue left after a mowing to help facilitate optimum growth. A lawn that is cut to about 2.25 inches is a healthy lawn. If these lumps make your lawn uncomfortable under foot then simply rolling your lawn will alleviate this distress.

However, in a heavy soil earthworm activity seems to make all the problems of a clay soil a little bit worse. The earthworm castings seem to be sticky, gloppy masses of close to concrete, not the type of soil conducive to plant growth. Over the years, I have been asked numerous times how to eradicate this pest.

There is no instant, magical way to eradicate earthworms with a spray or drench. In fact, even trying to do so would be devastating to all living organisms in the soil that help make up the great diverse environment in the soil we cannot see. If you have a heavy soil and find earthworms are not helping, the best solution is to add lots of organic matter.

In effect you will be “feeding the worms” and giving them more organics to break down and improve your non-friable soil. Use coarser organics like grass clippings and chopped leaves to provide lots of munching prior to becoming humus. Do not give up as this process will take some time, and lots of organic matter.

We as gardeners are always trying to improve the soil tilth, but it is always a short-term solution. Earthworms, believe it or not, are the best long-term solution for a healthy soil as they are able to: improve the soil structure, mix and till the soil, help in humus formation and increase the availability of nutrients in the soil.

Next time you get concerned about too many earthworms, remember that they are the army building your soil into a better entity, and perhaps instead of worrying about them, take you spade out to the garden, dig a few earthworms and go fishing.

— Hanbidge is a horticulturist with the Saskatoon School of Horticulture and can be reached at 306-931-GROW(4769); by email at [email protected] or check out our website at www.saskhort.com

05 Mar The Importance of Garden Worms

Two Different Earthworm Jobs

Let’s talk about two big jobs that earthworms do, and which ones do them.

  1. Worms that compost: Worms that compost are usually smaller, live closer to the soil surface, and can tolerate higher temperatures and a more crowded environment. They prefer to eat organic matter like compost more than they do actual soil, and as a result, produce richer worm “castings” (worm poop). These are the earthworms you see in your compost pile, and the ones that are recommended for vermicomposting indoors. Common names to look for are “red wigglers” or “red worms.”
  2. Worms that move the earth: These earthworms move deeper in the soil, and tend to be larger as a natural requirement for the job they do. They help aerate the soil and improve soil, and prefer cooler soil and less crowded living conditions (they don’t mind roomies but like their own space). And while they also produce valuable castings, theirs tend to be less rich ones than their compost-eating cousins. These earthworms are usually called “nightcrawlers” — and while they’re the ones that fishermen love because of their size, these are not the type you want to add to your kitchen worm composting project because they prefer digesting soil rather than compost ingredients.


There are over 1000 species of native worms in Australia and approximately 80 introduced species that are beneficial as well.

Earthworms are excellent buddies to have in your garden. They return nutrients to the soil from organic matter such as fallen leaves, vegetable peelings, fruit scraps, hair clippings, and even old paper. These nutrients are important for plants and will greatly enrich the soil in your backyard.

They are not all small and brown – some Australian native worms are enormous. The Guinness Book of Records records the ‘Gippsland Giant’ growing to 3 metres. A species found in north-eastern New South Wales often grows longer than 150 cm and is as thick as a garden hose. But you are unlikely to find one of these monsters in your backyard.

Earthworms can eat up to half their bodyweight in organic material every day. By tunnelling and burrowing underground, earthworms aerate your soil, making it less compact and easier for water to penetrate and get to plant roots.

Worms have good reason for staying under the ground – not only do they need to stay moist, but they are the favourite food of many birds.

Avoid using chemicals or pesticides in your garden as they can enter the soil and cause your worms to become sick. If you have recently wormed your pet, collect any droppings from the garden and put them in the bin, as these chemicals can kill earthworms.

By putting your organic waste like fruit and veggie peelings, scraps, and even shredded paper in a compost or worm farm, you’re reducing the amount of rubbish you send to landfill.

Be a Backyard Buddy

Earthworms love:

  • Dead organic matter like fallen leaves, vegetable peelings, and fruit scraps, which they pull underground and eat.
  • Mulch & groundcover which keeps the soil underneath cool and moist.
  • Night time when they emerge from the soil to grab leaves and scraps to pull underground and eat. They stay underground during the day so they don’t dry out and to avoid predators.
  • Tunnelling to get around underground. This also aerates your soil.

But they don’t like:

  • Strong flavours such as citrus, pineapple, chilli, onion, garlic or shallots.
  • Meat, chicken or fish as earthworms are vegetarians.
  • Chemicals, oil or pesticides, which make them sick.

Be a Buddy to Earthworms

Try to:

  • Make a compost heap in your garden.
  • Cover up any worms you unearth when digging in the garden. They don’t like to be exposed.
  • Mulch your garden beds, grow groundcover, or let leaf litter be your mulch. This will provide plenty of worm food and keep the soil moist.
  • Collect any veggie peelings, fruit scraps, old shredded papers and put them in the garden for worms to eat.
  • Start a worm farm and make worm juice (liquid fertilizer) which is great for your plants. In good conditions worms breed every 7-10 days, eggs take about 21 days to hatch, and in 2-3 months the new worms are ready to breed. The population will double every 2-3 months and will eat all your scraps and organic material.


  • Using chemicals, pesticides or insecticides in your garden.
  • Overwatering your garden as worms like damp but not extremely wet soil.
  • Putting meat, dairy, sugary products, spicy vegetables, or citrus scraps in the garden as worms don’t like to eat them and they can attract other insects and rats.

Don’t be surprised if :

  • You see really, really long worms.
  • Earthworms squirt out lots of liquid if you pick them up.
  • You see earthworms in puddles after heavy rains.

A few more Earthworms facts

  • Worms have both male and female organs, but they still need another worm in order to reproduce. Worms lay eggs which hatch after about three weeks.
  • Earthworms don’t have lungs, and instead breathe through their skin.
  • Worms are made up almost entirely of water, and so they love to be in damp soil during the day where it is cool and moist, so they don’t dry out or become too hot.
  • Worms don’t have eyes but they do have light-sensitive tissues near their heads to detect light.
  • Earthworms don’t have teeth. Tiny stones in their gut help grind up what they eat.

Related Factsheets:

Worms have both male and female organs, but they still need another worm in order to reproduce. They lay eggs which hatch after about three weeks. Earthworms don’t have lungs, and instead breathe through their skin! Worms are made up almost entirely of water, and so they love to be in d..

How earthworms can help your soil

Little is known about the behaviour of earthworms in Australia. Much of the research that has been done has been carried out in southern Australia, where the climate and soils are quite different to the NSW North Coast. For this reason, this information is very general in its approach. However, the principles established from research on earthworm ecology can be applied generally to most soils and climates.

Benefits of earthworms

By their activity in the soil, earthworms offer many benefits: increased nutrient availability, better drainage, and a more stable soil structure, all of which help improve farm productivity.

  • Improved nutrient availability
    Worms feed on plant debris (dead roots, leaves, grasses, manure) and soil. Their digestive system concentrates the organic and mineral constituents in the food they eat, so their casts are richer in available nutrients than the soil around them. Nitrogen in the casts is readily available to plants. Worm bodies decompose rapidly, further contributing to the nitrogen content of soil.
    New Zealand research shows that worm casts release four times more phosphorus than does surface soil. Worms often leave their nutrient-rich casts in their tunnels, providing a favourable environment for plant root growth. The tunnels also allow roots to penetrate deeper into the soil, where they can reach extra moisture and nutrients. Earthworm tunnelling can help incorporate surface applied lime and fertiliser into the soil.
  • Improved drainage
    The extensive channelling and burrowing by earthworms loosens and aerates the soil and improves soil drainage. Soils with earthworms drain up to 10 times faster than soils without earthworms. In zero-till soils, where worm populations are high, water infiltration can be up to 6 times greater than in cultivated soils. Earthworm tunnels also act, under the influence of rain, irrigation and gravity, as passageways for lime and other material.
  • Improved soil structure
    Earthworm casts cement soil particles together in water-stable aggregates. These are able to store moisture without dispersing. Research has shown that earthworms which leave their casts on the soil surface rebuild topsoil. In favourable conditions they can bring up about 50 t/ha annually, enough to form a layer 5 mm deep. One trial found worms built an 18-cm thick topsoil in 30 years.
  • Improved productivity
    Research into earthworms in New Zealand and Tasmania found earthworms introduced to worm-free perennial pastures produced an initial increase of 70–80% in pasture growth, with a long-term 25% increase: this raised stock carrying capacity. Researchers also found that the most productive pastures in the worm trials had up to 7 million worms per hectare, weighing 2.4 tonnes. There was a close correlation between pasture productivity and total worm weight, with some 170 kg of worms for every tonne of annual dry matter production.

How to encourage earthworms

Because earthworms do not like soil that is too acid, alkaline, dry, wet, hot or cold, their presence is a good indicator of soil conditions suitable for plant growth.

  • Ensure soil pH (CaCl2) is above 4.5
    Earthworms do not like acid soils with pH (CaCl2))* less than 4.5. The addition of lime raises pH and also adds calcium. Earthworms need a continuous supply of calcium, so are absent in soils low in this element. South Australian research found that earthworm numbers doubled when pH(CaCl2) rose from 4.1 to 6.7.
    • pH can be measured in water or calcium chloride (CaCl2). The CaC12 method is more accurate and gives values of about 0.5–0.8 lower than water pH. A pH(CaCl2) of 4.5 measures about 5.0–5.3 in water.
  • Increase organic matter
    Earthworms feed on soil and dead or decaying plant remains, including straw, leaf litter and dead roots. They are the principal agents in mixing dead surface litter with the soil, making the litter more accessible to decomposition by soil microorganisms. Animal dung is also an attractive food for many species of earthworms. The following farming practices provide food for earthworms.
    • Permanent pasture: Permanent pasture provides organic matter as leaves and roots die and decay. Pasture slashings and manure from grazing animals are also good sources of organic matter in pasture.
    • Green manure crops: Green manure crops are fodder crops turned into the soil to provide organic matter to benefit the following crop. The crops are grazed or slashed, sometimes pulverised, and then left on the surface or turned into the soil.
    • Crop stubble: Stubble is an important source of organic matter. Burning stubble destroys surface organic matter, and this affects worm numbers. It is best to leave stubble to rot down, and sow following crops into the stubble using aerial sowing, direct drill or (at least) minimum tillage. All these techniques mean less cultivation, and this also encourages earthworms.
    • Rotations: Rotating pasture with crops helps build up organic matter levels and earthworm numbers.
  • Reduce use of some fertilisers and fungicides
    Highly acidifying fertilisers such as ammonium sulfate and some fungicides reduce worm numbers. Researchers have found that orchards sprayed with bordeaux or other copper sprays contain few earthworms and have peaty surface mats and poor soil structure.
  • Keep soil moist
    Worms can lose 20% of their body weight each day in mucus and castings, so they need moisture to stay alive. Groundcover such as pasture or stubble reduces moisture evaporation. Decaying organic matter (humus) holds moisture in the soil. In dry times some species burrow deep into the soil and are inactive until rain ‘reactivates’ them.
  • Improve drainage
    Worms need reasonably aerated soil, so you may need to drain or mound soil in wetter areas to prevent waterlogging.
  • Reduce soil compaction
    It is difficult for earthworms to move through heavily compacted soil, so keep vehicle and animal traffic to a minimum in wet conditions.
  • Reduce cultivation
    Ploughing soil reduces earthworm numbers. Researchers have found that after four years, zero-tilled paddocks had twice as many worms as cultivated soils. However, shallow cultivation may not affect worm numbers.
  • Protect from climatic extremes
    Earthworms are intolerant of drought and frost, and do not like dry sandy soils. They are active only when the soil is moist, and are inactive when it is dry. Organic matter cover helps reduce the effect of climatic extremes, and retains soil moisture.

How to introduce earthworms

  • Change management practices
    If you do not have many earthworms in your soil, introduce some of the practices described above. It is surprising how quickly they build up in favourable conditions.
  • Transplant pasture
    Cut pasture sods from areas with high worm populations and transfer them to worm-free areas. New colonies will establish within a couple of years as long as there is plenty of organic matter and soil and climatic conditions are favourable. It is important that you transplant pasture, not just worms. Do not try and transplant compost worms into agricultural soils. Species that thrive in compost will not survive the harsher conditions of paddock soils, which dry near the surface.

Earthworms can be an indicator of soil health

There are many different parameters that can be used to determine soil health. One common measure is the number of earthworms that are found in the field. To survive, earthworms need moist soils that have sufficient residue or organic matter for food. As part of MSU Agriculture Innovation Day – Focus on Soil on Aug. 24 in Frankenmuth, MI, attendees can learn more about earthworm’s role in maintaining soil health.

Earthworms perform several important functions in soil. They improve soil structure, water movement, nutrient cycling and plant growth. They are not the only indicators of healthy soil systems, but their presence is usually an indicator of a healthy system.

There are some considerations that you need to be aware of when looking for earthworms. If earthworm counts are taken when the soil is dry, the earthworm numbers may not be a good representative of the field. Earthworms may have moved deeper or to areas of the field that have more moisture. Earthworm populations will be high around areas with high organic matter. If such an area is consistent throughout the field, go ahead and test. If it is not a good representative of the field, choose another spot to test that is more uniform with field conditions. To get the best results, it is advisable to test several times during the growing season, and then take an average of the earthworm numbers.

Materials that you will need to measure worms in the field:

  • Tape measure
  • 2 liters of tap water
  • Hand trowel or shovel
  • Container to collect worms
  • Solution of 2 tablespoons of mustard powder dissolved in 2 liters of water

Once you have your materials gathered you are ready to count earthworms.

Step 1: Measure a square foot in the test area and dig down 12-inches.

Step 2: Collect and count the number of worms found. If possible, differentiate worms by type. For example, label as earthworms, red worms, etc.

Step 3: (Optional) Level out the bottom of the hole, and pour the mustard solution slowly. Deep burrowing worms should come to the surface within 5 minutes. Collect and count the worms that come to the surface.

Step 4: Count and record the total number of earthworms that are collected.

Another method to count earthworm populations takes more time but is less labor intensive.

Step 1: Measure a square foot in the test area.

Step 2: Slowly pour 2.5 gallons of the mustard solution in the test area, allowing the water to infiltrate through the soil without pooling and running off. This could take several minutes depending on soil type and moisture.

Step 3: Collect and count the earthworms as they come to the surface for ten minutes after the test area is saturated with the mustard solution.

Earthworm counting is only one way to determine soil health. There are other measures that farms can use, especially with soils that are sandy and droughty, to determine the health of their soil.

To learn more about soil health, join other farmers on Aug. 24 as Michigan State University Extension hosts an educational field day focusing on soils at the Saginaw Valley Research and Extension Center near Frankenmuth, Mich. The MSU Agriculture Innovation Day: Focus on Soils program is a great opportunity for farmers to learn about the cutting-edge research conducted by MSU scientists on soil health topics ranging from nutrient management and soil quality to compaction and tile technology. The event is free and open to all. It begins at 8 a.m. with registration. Nine educational sessions will be conducted throughout the day, and attendees can also view displays and demonstrations. A lunch will be provided.

How do earthworms eat and poop — and other surprising facts

How do earthworms eat?

They do not have teeth. A liplike extension over the mouth helps direct food into the mouth, where the muscular pharynx (throat) grabs it, coats it with saliva and pushes it down the esophagus into the crop, where it is stored before moving on to the gizzard. There it is crushed and ground apart before moving into the intestine, where it is broken down further by digestive enzymes. Some of the food is passed into the bloodstream for use by the earthworm, and the rest passes out the anus as castings (worm poop).

Do earthworms have eyes?

(Alla Dreyvitser/The Washington Post/iStock)

No. They have receptor cells in their skin that are sensitive to light and touch. They will move away from light because heat from the sun or a light source will dry out their skin and kill them.

How do earthworms breathe?

Earthworms do not have lungs; instead, they breathe through their skin. Their skin needs to stay moist to allow the passage of dissolved oxygen into their bloodstream. Earthworm skin is coated with mucus, and they need to live in a humid, moist environment.

How do earthworms move?

Earthworms have groups of bristles on each segment of the body that move in and out to grip surfaces as they stretch and contract their muscles to push themselves forward or backward. They tend to move forward.

If an earthworm is cut in half, will it regenerate into two worms?

No. The half with the worm’s head will survive if the cut is after the segments containing vital organs. But the other half will not grow a new head nor other vital organs.

Joseph Brownlie holds and watches a ‘red wiggler’ worm. (Katherine Frey/The Washington Post)

Which end is the head?

The head is at the end closest to a swollen band encircling an adult earthworm.

What is that swollen band?

The swollen band is called a clitellum. After copulation, it secretes a cocoon in which eggs and sperm are placed for conception and development.

How do they reproduce?

Earthworms are hermaphrodites, so individuals have both female and male organs. They mate by aligning themselves in opposite directions at their gonadal openings and exchanging packets of sperm. Each earthworm will form an egg capsule in its clitellum and pass it into the environment. The egg capsule is golden brown and looks like a tiny lemon the size of a match head. Two to seven Eisenia fetida babies (three, on average) will hatch from an egg capsule in 30 to 75 days.

Can earthworms survive the winter outdoors?

To survive winter, other species of earthworms can burrow into the soil below the frost line. But composting earthworms don’t burrow, so they produce cocoons that allow their babies to live through cold weather. People who are vermicomposting can counteract cold by insulating their worm bins.

How long do worms live?

The Eisenia fetida earthworms’ life expectancy is approximately 4½ to five years.

Will the worm population in a bin keep growing?

If the bin has the proper conditions (i.e., moisture level, temperature), the earthworms will thrive and reproduce. After about four to six months, you may need to thin the population. Do not put the worms in your yard because it is not their natural habitat and they probably will not survive.

For more information, see here.

Earthworms Are an Essential Part of an Organic Garden

Healthy soil is an integral part of an organic garden, and earthworms make healthy soil. They tunnel through and ingest the hardest of hardpans, and the burrows aerate the soil. Worm castings add fertilizer full of macro- and micronutrients, which helps create an optimum growing environment for your garden.

There are several species of earthworms, and they burrow in as many different directions. Some worms make shallow burrows and devour surface litter, others go straight down several feet, and still others move horizontally – while some tunnel completely at random! No matter the methods, worm burrows allow water and air to penetrate the soil while making spaces for deep root growth.

Think of worms as a rototiller turning the soil. The shallow dwellers take organic matter from the surface of the ground down into their burrows, while the deeper dwellers pull up nutrients and minerals not accessible to plant roots. Worms till your soil and make a loose, friable planting medium with excellent aeration and drainage without fossil fuels! In one year on one acre, worms can move eight tons of dirt and excrete enough castings to make 2” of fresh, nutrient-packed soil, according to Darwin. Check out this video of earthworms making short work of a pile of compost, grass, and sawdust.

Worms eat dirt, animal manure, and organic matter such as leaves, dead roots, and grass. Their digestive systems turn their meals into humus full of necessary plant nutrients. Their castings contain more nitrogen, phosphorus, potassium, and calcium than the surrounding soil. Worm poop is a concentrated form of all the ingested nutrients, which are immediately available for uptake by plants.

Attracting Worms To Your Garden

You couldn’t ask for better free help to improve your soil! Here are five ways to lure night crawlers and field worms to your garden:

1. Keep your garden well-watered and mulched. Worms like a cool, damp environment. Protect them from extremes weather. Plant a cover crop over the winter to keep them from freezing.

2. Be sure your pH is above 4.5. If the soil is too acidic, the worms will go to a more alkaline area. Add lime to a very acidic soil to raise the pH and provide calcium, which worms love and need!

3. Feed them by adding organic matter to your garden in the form of compost, shredded leaves, and grass clippings.

4. Do not use synthetic fertilizers and pesticides. Worms will move to an organic, natural area.

5. Turn your soil with a flat tined fork or a broadfork. A rototiller or shovel will damage burrows and injure the worms.

Growing Your Own Worms

Start a compost pile of yard waste and fruit and vegetable kitchen scraps. The organic matter will attract worms, and they will turn it into compost, which will feed the worms in the garden.

Build a worm bin for indoor composting using red wigglers or branding worms. You will get nutrient-rich compost and liquid fertilizer to use on your plants. Worms will also multiply in a bin, so you’ll always be adding to your population.

Feed the worms, and they will feed you!

Would you like to be the first to hear about our new products and more?
Sign up for our Nature’s Path Newsletter.

Earthworms A Gardener’s Best Friend

  • Improve the physical structure of the soil.
    Improve water filtration rates and absorption rates helping the soil to drain better. Less runoff equals less watering and less erosion.
  • Their tunneling activity improves soil aeration, porosity, and permeability.
  • Increases moisture absorption by the soil and helps make moisture available to plants. Castings absorb water faster than soil; castings hold more water than equivalent amounts of soil. Bhawalker Earthworm Research Institute
  • Castings have the ability to absorb moisture from the air and hold it in a manner that plants can use. Bhawalker Earthworm Research Institute
  • 25 earthworms per square foot of soil equal 1 million earthworms per acre. Studies in England have shown that in healthy soil forty tons of castings per acre pass through earthworms bodies daily. A new USA study indicates 12 million worms per acre which move 20 tons of earth each year.
  • Studies have shown that with good food sources and favorable conditions, a field might have over 100 nightcrawlers per square yard. National Soil Tilth Lab
  • One earthworm can digest 36 tons of soil in one year. US Soil Conservation Office
  • The tunneling activity of worms helps breakup hardpan and other compacted soils.
  • Studies have shown that 30% of a field’s respiration during the cold wet winter to spring months is due to earthworms.
  • A study in European orchards found that earthworms could increase the pore space in soil by 75 – 100% and that earthworm burrows accounted for b of a soils air-filled pore. Earthworm Ecology and Biogeography in North America, 1995.
  • Improve soil fertility.
    Bring up minerals from deep in the subsurface that are often in short supply in surface layers.
  • Earthworm activity counteracts leaching by bringing up nutrients from deep in the soil and depositing them on the soil’s surface as castings.
  • The burrows also allow roots to easily go down deeper into the soil and get nutrients they could not ordinarily reach.
  • Removes litter from soil surface – earthworms eat the litter and leave the nutrients in their castings for plants to use as a natural fertilizer that is non-polluting.
  • Earthworms process compost residues and waste products. The bacteria and other microbes in a worm’s gut help destroy harmful chemicals and breakdown the organic wastes.
  • Create fertile root channels – the mucus lining of abandoned burrows are an excellent source of nutrients and root growth promoting hormones.
  • They make plant nutrients more available, worms concentrate minerals in their castings in a form that is easy for plants to absorb.
  • Earthworms chelate nutrients, making minerals available to plants that would otherwise be in a form that would be chemically unavailable.
  • Worms stimulate beneficial microbial populations; nitrogen fixing bacteria are more numerous near earthworm burrows and in their castings. One study on bacteria and actinomycetes found densities from 10-1,000 times greater. Earthworm Ecology and Biogeography in North America, 1995.
  • Plant growth stimulants such as Auxins are produced in the castings, these hormones stimulate roots to grow faster and deeper.
  • Worms neutralize soil pH, cast analysis shows that the product coming out of the back end of a worm is closer to neutral than what goes in the front end.
  • Analysis of earthworm castings reveal that they are richer in nutrients than surrounding soil, often 3 times more calcium, several times more nitrogen, phosphorus, and potassium. K.P. Barley, Advances In Agronomy, Vol. 13, 1961
  • Nitrogen fixing bacteria live in the gut of earthworms and in earthworm casts and higher nitrogenase activity, meaning greater rates of nitrogen fixation are found in casts as compared to surrounding soil.
  • One study found that earthworms are responsible for passing nitrogen to the soil at a rate of 100 Kg N per ha per year. Earthworm Ecology and Biogeography in North America, 1995.
  • The earthworms gut is a natural bioreactor, which increases the beneficial microbial density in the material it excretes to 1,000 times that of the surrounding soil. Worm Digest, Winter 1994.
  • Improve plant growth and health
  • Tests have shown that crops grown in earthworm-inhabited soil increased yields from 25% to over 300% than in earthworm-free soil. K.P. Barley, Advances in Agronomy, vol. 13, 1961, p. 262-264
  • Earthworms help eliminate thatch in lawns and grassy areas by eating and digesting the plant debris.
  • Studies have shown that soils rich in earthworms have less of the harmful nematodes like root feeders.
  • Earthworms create soil conditions that discourage populations of soil organisms such as insects, nematodes and others that are harmful to plants.
  • By passing soil and organic matter through their bodies, gradually make acid soil less acid and alkaline soil less alkaline. The Rodale Book Of Composting, 1993
  • A recent study found that earthworm produced compost (vermicompost) dramatically increases germination and growth in many plants. Adding only 5% of the compost to commercial growing media (95%) significantly increased plant growth. Dr. Clive Edwards, Ohio State University, Nursery Management & Production, January 1995
  • Research has shown that twice as many roots grew in pure worm castings than in sphagnum. Dr. Clive Edwards, Ohio State University
  • Many species of earthworms actually eat the bad microbes (fungi, bacteria, etc.) that are plant pathogens and in the process they also increase the good beneficial microbes.
  • It has recently been discovered that in feeding, earthworms consume spores of mycorrhizae, a beneficial fungi that help roots take up nutrients. These spores are deposited in the worm castings, deep in their burrows, where roots easily find them as they grow. The Avant Gardener, p. 87, 1995.
  • Studies have shown that earthworms can increase barley yields 78-96%, spring wheat and grass yields 400%, clover yields 1,000%, and peas and oats by 70%. Other studies found that yields were increased for millet, soybeans, lima beans, and hay. Studies in New Zealand found that earthworms at least doubled yields in all cases and adding worms to crops has become standard agricultural practice. Earthworm Ecology and Biogeography in North America, 1995.
  • Experiments at Tennessee Technological University found that 10% vermi-compost in a potting mix improved the germination of seeds of low viability (Echinacea purpurea) by 43%
  • Researchers at Oregon State University have found that a tea made from the worm castings speeds up the sprouting of hard to germinate seeds following just one hour of pre- soaking.
  • A large earthworm population suppresses weed growth
  • The tunneling activity of earthworms prevents many of the conditions that weed seeds need to germinate.
  • Earthworms often eat weed seeds and either destroy them or reduce their ability to germinate.
  • Earthworms stimulate the growth of microorganisms in the soil and some weed seeds are destroyed by these microorganisms.
  • Some microorganisms (bacteria and fungus whose growth is stimulated by worms) live in a symbiotic relationship with plant roots and help plants grow better hence shading out weeds and out competing them for water and nutrients.
  • Worms often help clean up dangerous chemicals in the environment
  • Researchers have found that bacteria living in the guts of worms breakdown (detoxify) many hazardous chemicals such as hexachlorocyclohexane (HCH), Organic Gardening, May/June 1993
  • Microbes living in worms have the ability to breakdown complex organic molecules like cellulose and lignin.
  • Improve water absorption and prevent erosion
  • Increase the water stability of the soil, earthworm castings can take a direct hit by a raindrop and maintain their shape, this reduces erosion and runoff hence helps the soil absorb water.
  • A research study conducted in Minnesota showed that earthworms added to cornfields increased water absorption rates 35 times over control fields without the earthworms, within a 6 week period. Acres USA, March 1994.
  • Soil in a field with 100 nightcrawlers per square yard, 2 inches of water (a very heavy rainfall) could be absorbed by the soil in 12 minutes. The same soil without earthworms took over 12 hours to absorb that much water. National Soil Tilth Lab
  • If the top 3 feet of soil contained 25% macropores (earthworm burrows) then that soil should be able to absorb at least a 9 inch rainfall without runoff. Natural Food & Farming, July/August 1991.
  • One study showed that on a sloping field with no-till practices, there were 155 earthworms’ holes per square yard and an average runoff of 0.08 inches per year. This compares to a tilled field with 6 holes per square yard and 4.9 inches of runoff per year. The average rainfall for this area is 39.4 inches. Natural Food & Farming, July/August 1991.
  • Scientists from the Agricultural Research Service found that grass and leave mulched plots had twice as many earthworms as those mulched with cornstalks. Water penetrated the earth-worm filled soil up to 4 times faster.
  • Chemicals produced in the earthworm cause the castings to form aggregates in the soil that are resistant to erosion.
  • Studies have shown that earthworms in soils can easily triple infiltration rates and cut run-off in half. Earthworms in Agroecosystems, 1995.
  • Some scientists now believe that earthworms have the potential to eliminate soil erosion
  • This could save society billions of dollars in erosion control, reduce pollution from dangerous synthetic chemicals and improve the environment.
  • In an acre of good soil researchers have found more than 1 million worms and 1,200 miles of earthworm holes or burrows.
  • Earthworms are valuable
  • One-million earthworms per acre is about 25 earthworms per square foot of soil. If one had 1 nightcrawler per square foot at a value of $1.00 per dozen then one would have $3,630 worth of earthworms. Full retail value of one million earthworms would be over $83,000. If earthworms would work only 100 days per year and eat their weight of soil and/or residues daily, then at that rate with one ton of earthworms per acre you would have 100 tons of earthworm manure (castings) per acre per year. This is about 2/3 inch deep layer over an entire acre of land. Natural Food & Farming, July/August 1991.
  • One million earthworms will have burrows which will have the equivalent space of 4,000 feet of 6 inch drain tile. At a installed price of $1.20 per foot for drain tile, those burrows are worth $4,800 per acre. Natural Food & Farming, July/August 1991.
  • Soil samples from a field not fertilized for 5 years but with a active earthworm population was analyzed. Based on the reported analyses it was found that 100 tons of earthworm castings will contain 4 lbs. of nitrate nitrogen, 30 lbs. of phosphorus, 73 lbs. of potassium, 90 lbs. of magnesium, 500 lbs. of calcium. That is the equivalent to a 4-69-86 fertilizer and 3/4 ton of limestone worth $34.15 per acre with no fee for spreading or transportation.
  • Research presented at the ISEE 5 (International Symposium on Earthworm Ecology at Ohio State University) point at earthworms being a important biomedical resource. It has been found that ingredients from earthworms have anti-cancer properties.
  • The bodies of earthworms are extremely nutrient rich from minerals to amino acids, proteins and vitamins. When earthworms die these nutrients are released into the soil.
  • How to attract and promote earthworms
  • Mulch all soil with organic mulches which help stabilize soil temperature and moisture. Earthworms love Native Mulch and grow big and fat in it.
  • Mulch provides food and shelter for earthworms. Compost is an excellent mulch and as a soil amendment to attract (food source) earthworms.
  • Agricultural chemicals such as salt based artificial fertilizers (i.e. 13-13-13), pesticides, etc. can kill earthworms. Even if a few pesticides do not kill earthworms, such as DDT, birds are killed when they eat the worms. Pesticide Reviews, Vol. 57, 1975.
  • Earthworms and other beneficial organisms are destroyed by synthetic chemical fertilizers and fungicides, pesticides, etc. (Reviews of Environmental Contamination and Toxicology, 1992). In the absence of earthworms, the soil becomes lifeless, sterile, nutrient deficient and develops lots of problems.
  • Studies have found that most organic fertilizers tend to have a positive effect on earthworms and increase population densities. Earthworm Ecology and Biogeography in North America, 1995.
  • Soils that are not tilled have 3-4 times as many nightcrawlers (surface feeding earthworms) as soils that are tilled in the spring or fall. Tilling greatly accelerates the breakdown of organic matter in the soil that worms need. National Soil Tilth Lab
  • Studies have shown that mulches produced from grass cuttings or leaves have twice the earthworm population than course mulches from straw or corn stalks, etc. National Soil Tilth Lab
  • Mulches made from wood wastes that have lots of “fines” or small particles sizes are easier for worms to use (swallow and eat). The increased particle surface area of the small sizes also allows for greater microbial activity that is preferred by worms.
  • Rough (unfinished) compost is one of the best worm-food mulches there is. The Avant Gardener, p. 87, 1995.
  • Types of earthworms, Over 3,000 worm species have been identified. Experts disagree as to what distinguishes one type of worm from another and if one species is a true earthworm or not. All soil worms are beneficial and most references lump all soil worms into the category of “earthworms”.
  • Two basic types of worms, those that feed on the surface and those that feed in the subsurface. The surface feeders eat plant residue, are generally large worms and live in vertical burrows often over 6′ deep. Subsurface feeders are smaller than surface feeders like nightcrawlers but outnumber them 9 to 1. They eat their way through the subsurface loosing, aerating and improving soil structure in the process.
    When worms are separated into “worms” and “earthworms” then following applies:
  • Redworms, often called manure worms, brandling worm, or red wigglers, they are reddish brown in color, and they live in the soil in the surface layer of decaying vegetation (litter). They feed on this layer, multiplying rapidly in numbers, expand into poorer surrounding soil and die thereby distributing the nutrients contained in the excess wastes over a larger area. Often used in small scale worm bins. Eisenia foetida and Lumbricus rubellus (tends to be more soil dwelling if large amounts of organic material are in the soil) are examples of redworm species.
  • Earthworms, often called soil processing worms, they are a burrower, a soil processor, eating dead organics and rock particles, grinding and excreting them as a finely ground mix which serves as food for bacteria. They tend to survive in harsh conditions better than redworms. They do not assimilate the organics to the same extent as redworms for themselves; hence they do not multiple as quickly as redworms whose assimilation rates are much higher. The higher rate of assimilation (redworms) means that the nutrients consumed by the redworms goes into building their own biomass while the earthworm passes on these nutrients in a soluble form in their castings.
  • Pheretima elongata, deep burrowing earthworm used in Bombay India to convert garbage into vermicompost. Recommended by Uday Bhawalker (Bhawalker Earthworm Research Institute) as the most efficient organic waste converter. Waste conversion occurs at the soil surface, not in a bin hence less material handling is required.
  • Lumbricus terrestris, called nightcrawlers, dew worms, rain worm, orchard worm, etc. They like soil temperatures less than 50EF. They are also dig burrows and do not like to have their burrows disturbed. They come to the surface to feed on dead grass leaves etc. drawing them into their burrow hence taking organic matter deep into the soil layer. A good garden worm.
  • Garden worms, Allolobophora caliginosa, A. chloritica, Aporrectodea turgida, A. tuberculata, etc. often found in pastures.
  • Most worms found in U.S. soils are not native
  • Some earthworms from the southern hemisphere can grow 3-5′ long, 1″ in diameter and weigh up to 1.3 pounds
  • Earthworms have many uses from soil farmer to food for animals. Most recently they are being used as a diagnostic tool since they have the ability to hyper accumulate toxins and environmental pollutants found in the soil (since they ingest soil). As a result they are often collected and their tissue analyzed for chemical contaminants
  • Earthworm Math
    25 earthworms/sq. ft. = 1 ton of worms/acre
    1 ton worms = 100 tons of castings or b” manure (castings) on surface per acre
    Macropore equivalent to 4,000 ft. of 6″ tile drain pipe per acre
    Nutrients added to 1 acre of soil each year:
    4 lbs of nitrate of nitrogen
    30 lbs of phosphorus
    72 lbs of potash
    90 lbs of magnesium
    500 lbs of calcium
    or in terms of a fertilizer analysis = 4-68-96 plus 3/4 ton of limestone for a nutrient value of $34.15/acre in 1998.
    • Allolobophora chlorotica – the green worm, native to U.S.
    • Aporrectodea rosea – the pink soil worm, native to U.S.
    • Aporrectodea trapezoides – the southern worm, native to U.S.
    • Aporrectodea turgida – the pasture worm, native to U.S.
    • Bimastos tumidus – often found in compost piles, tolerates medium C:N ratios and cooler temperatures better than Eisenia foetida , multiplies rapidly in old straw and spoiled hay, hardy to Z-5 and will survive in ordinary soil conditions hence once established it would survive without extensive preparations. Earthworm Ecology and Biogeography in North America
    • Chumiodrilus zielae:
    • Eisenia foetida: (the tiger or brandling worm), often used for composting sometimes called E. andrei, (composter or surface worker species)
    • Eudrilus eugeniae: (African nightcrawler) do well but cannot withstand low temperatures,(composter or surface worker species)
    • Hyperiodrilus africanus: (west African)
    • Lumbricus rubellus: (common redworm or red marsh worm), used in Cuba’s vermicomposting program, (composter or surface worker species), native to U.S.
    • Lumbricus terrestris: nightcrawler, native to U.S.
    • Millsonia anomala:
    • Perionyx excavatus: (Asian species) do well but cannot withstand low temperatures. (composter or surface worker species)
    • Octolasion tyrtaeum – woodland white worm, native to U.S.
    • Pheretima elongata: bigger, stronger and livelier than common species such as red worm (esienia foetida). It is a deep burrowing worm. Recently found in Missouri. Agricultural Research Service scientists are attempting to breed and spread this species as it would be useful for breaking up hardpans and for erosion control (increase infiltration). Avant Gardener, p.87, 1995.
    • deep burrowing earthworm: used in Bombay India to convert garbage into vermicompost. Recommended by Uday Bhawalker (Bhawalker Earthworm Research Institute) as the most efficient organic waste converter. Waste conversion occurs at the soil surface, not in a bin hence less material handling is required.
    • Polypheretima elongata:
    • Ponotscoex corethrurus: (common through-out humid tropical zone)
    • Pontoscolex corethrurus:
    • Stuhlmannia porifera:
  • Earthworm predators:
    • Artioposthia triangulata – “flatworm”, from New Zealand, destroying earthworms in Great Britain, worm is dark brown, flattened with cream speckled margins, likes moist conditions with moderate to cool temperatures.
    • Australoplana sanguinea – “flatworm”, from Australia, destroying earthworms in Great Britain, tolerates warmer and drier conditions than A. triangulata


The Earth Moved, by Amy Stewart, Algonquin Books, P.O. Box 2225, Chappel Hill, North Carolina 27515 ISBN 1-56512-337-9

The Biology of Earthworms, C.A. Edwards and J.R. Lofty

Earthworms, K.E. Lee

Worms Eat My Garbage, Mary Appelhof, ISBN 0-942256-03-4

Worm Digest Magazine, P.O. Box 544, Eugene, OR 97440-9998

The Farmer’s Earthworm Handbook: Managing Your Underground Moneymakers, David Ernst, Lessiter Publications, Brookfield, Wisconsin. 1995.

“Worm Wise News”, International Worm Growers Association, P.O. Box 900184, Palmdale, CA 93590

Soil Biology & Biochemistry, Special Issue: 5th International Symposium on Earthworms Ecology, ISSN 0038-0717



Twin Oaks Farm (Georgia Brown Nose…a heat tolerant worm)
Jim McCarter
Rt. #1 Box 78A
Purdon, Tx 76679-9801
(817) 578-1272

Rabbit Hill Farm
Jay Mertz
Rt. 3 Box 2936
Corsicana, Tx 75110
(903) 872-4289

Earthworm Institute
City of Grapevine
Larry Wilhelm
(817) 424-0540


Brown’s Worm Farm
Rosemary Brown
Box 284
Marietta, OK 73448
(405) 276-3897

Flowerfield Enterprises (good source of educational material for children)

Mary Appelhof (“The Worm Lady”)
10332 Shaver Road
Kalamazoo, MI 49002
(616) 327-0108

Jim Knight
Rt. 2 Box 183
Eudora, AR 71640
(510) 294-2603

Southern Worm Enterprize
12118 Marilyn Lane
Hammond, LA 70403
(504) 294-2603

Willingham Worm Farm
Rt. 1 Box 241
Butler, GA 31006


Gardener’s Supply Company
128 Intervale Rd.
Burlington, VT 05401
(800) 955-3370

Garden’s Alive
5100 Schenley Pl.
Lawerenceburg, IN 47025
(812) 537-8650

Peaceful Valley Farm Supply
P.O. Box 2209
Grass Valley, CA 95945
(916) 272-4769

Lots of info here, let me first say I do raise worms for a living, I dont know everything, but I do know there is tons of miss information out there.
Depending on where you live, as to what type of worm is in your yard, manure pile, field, golf club, keep in mind the same area may have several types in the same location. there is literally thousands of types.
even the “red worm” has many, many different species, depending on who you talk to, as to what kind it is.
when you buy red worms from one person, they will be different from another, all say “red worm” and in fact, to that person, they are……..
Worms can be any species and “wild” or “domesticated” some don’t domesticate well, so they are not raised as bait or vermiculture…..the worms in your yard—–no mater what kind, are “wild”
the ones you buy online or in a store are domesticated, with the exception of the Canadian night crawler, and those are generally picked from golf course’s in cold climates. ever put a wild bird in a cage, or let a domestic bird go. neither will do well…..same with worms. they will, co-exist in raised beds, I add my castings to my beds, and as the eggs hatch it helps them become more “wild” in a sense. If you put some meal or coffee/tea grounds in your beds, and cover that spot with a piece of black plastic, worms will come to it. “wild” worms, no mater what speicise do not breed well in captivity, have been raising and selling worms since 1975……..no expert, just some of what I have learn t…..

Adding Worms to Compost: Should I put Worms in my Compost Bin?

“Red wigglers are said to be able to process half their body weight in food every day”!

They also tolerate crowded conditions and can grow into large populations. A small number of red wigglers will reproduce quickly. The resulting compost (sometimes referred to as vermicompost) is highly beneficial for your plants.

So where do you find these handy little creatures? Unfortunately, you probably won’t find them in your backyard. If you want to give red wigglers a try you can sometimes pick them up from your local nursery, or you can order them online (these ones on Amazon are great value and come from a well reputed supplier).

Once you’ve got some red worms, you can easily add them to a closed bin or composting tumbler, but also an open bottomed compost bin. As long as they have plenty of organic waste for food they will thrive. Introduce them to your compost by gently spreading them out. Add some small pieces of food scraps (the smaller scraps break down faster). Then cover the worms with bedding soil to prevent them drying out and to prevent fruit flies turning up for the feast.

Earthworms vs Red Wigglers

Earthworms on the other hand are somewhat different.

A compost heap can be a relatively harsh environment for ordinary earthworms. The microbes feeding on waste vegetation can increase the temperature of the composting mass. Earthworms don’t do well in these hot temperatures compared to red wigglers which have a higher tolerance for temperature differences (they can survive at temperatures between 32 and 95°F / 0 – 35°C).

Another difference between red wigglers and native earthworms is their diet. Red wigglers will eat food waste and rotting vegetation, whereas earthworms get their nutrients directly from the soil or from composting material.

Earthworms are still a useful guest to have in your bin. It’s likely you’ll find worms from your garden inside an open compost heap. However, in extremes of heat, cold, or moisture, earthworms will prefer to leave the compost pile and bury themselves in the soil.

Why worms are good for compost

Worms are helpful to composting for a few different reasons. Worms are basically one long digestive tube.

Yep… Stuff goes in one end and comes out the other! In the process, several good things happen.

Composting material gets broken down, both physically grinded in the digestive tract and by the worms digestive juices. The worms manure (known as casts) actually comes out richer in nitrogen, organic matter, and bacteria than what went in.

Worms also improve the structure of the compost by their tunneling habits. Their tunnels allow better air and water circulation within the compost which encourages aerobic bacteria to do their job of decomposition.

Leave a Reply

Your email address will not be published. Required fields are marked *