SOIL IS THE STRATEGY.
Farm Composting Worms – for Manure, Horse Manure, Vermicomposting & Biological Compost Systems
Farm Composting Worms – for Manure, Horse Manure, Vermicomposting & Biological Compost Systems
2kg + one FREE Coir Bedding Block
£84.95
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£84.95
Need more than 20kg?
Please talk to us.
At genuinely large scale, the right starting population depends on your feedstock, active bed area, temperature, system design and how quickly you want to process material. We'd much rather understand what you're doing than simply sell you another 20kg of worms.
Pickup available at Lower Blakemere Farm
Usually ready in 5+ days
We Deliver by hand within 10 Miles or can send with our courier.
Live composting worms for farms, stables, smallholdings, market gardens, manure systems, IBC worm composters and Johnson-Su bioreactors. Supplied in proper farm quantities, with a FREE coir bedding block with every order.
At Lower Blakemere Farm we've worked with composting worms for decades through Wiggly Wigglers, and increasingly we're using them as part of the biological systems on the farm itself. We have worms working in an IBC system, we use them in our Johnson-Su bioreactor, and we introduce them into our cattle manure once the Bokashi and initial composting stages have finished and the material has cooled enough for them.
We don't breed the worms ourselves and we aren't claiming to be worm farmers. We source them from specialist producers. What we do have is a great deal of practical experience of using worms, composting with them, understanding the conditions they need and working out how they fit into a bigger farm system. Our current mix contains Tiger/Brandling Worms (Eisenia fetida) and Dendrobaena (Dendrobaena veneta), the same specialist surface-dwelling composting worms we supply through Wiggly Wigglers.
And perhaps the most important thing to understand is this:
These aren't worms to scatter across your fields. They are livestock for your composting system.
Most farms already have the raw materials.
We have manure.
We have bedding.
We have crop residues and other suitable organic matter.
The question is whether we regard that material as waste that needs moving, or as a resource we can biologically process and put back into the soil.
A good vermicomposting system can:
- Reduce the amount and bulk of manure and organic material that needs managing.
- Turn coarse manure and bedding into fine, dark vermicompost.
- Produce a valuable soil amendment from something you already have.
- Transform nutrients into different, often more plant-available forms rather than buying another input.
- Increase the fragmentation and microbial processing of organic matter.
- Work particularly well as a finishing stage after hot composting or Bokashi.
- Build its own workforce — healthy composting-worm populations reproduce.
- Work with cattle manure, horse manure and many other suitable farm wastes.
- Fit into IBCs, beds, bays, windrows and Johnson-Su systems.
- Produce solid vermicompost that can also be used to make fresh biological water extracts.
- Help return food and habitat to the wider soil biology — including the native field worms already living in your soil.
It is a wonderfully simple bit of enterprise stacking.
You've already paid to grow or buy the feed. You've paid for the bedding. You've fed the animal. You've got the manure.
Why not get another job out of it?
“The worms aren't adding fertility from nowhere. They're helping us make much better use of the fertility we've already got.”
— Lower Blakemere Farm
We think horse manure could be one of the most useful applications of farm-scale worm composting.
Anyone with horses knows the problem.
The horse eats at one end and, with impressive efficiency, produces an ever-growing mountain at the other.
Multiply that by a few horses, add straw or shavings and twelve months of mucking out, and suddenly manure storage becomes a significant job in its own right.
Horse manure is a well-established vermicomposting feedstock. Studies using Eisenia fetida have shown that horse dung can support worm growth and successful vermicomposting, while research specifically comparing conventional pre-composting and Bokashi pre-composting followed by vermicomposting found horse manure performed particularly well in that staged system.
That's useful because the biological sequence we're interested in is exactly that:
fresh manure → pre-composting → cooling → worms → vermicompost.
What about the bedding?
This matters.
A heap of mostly horse dung is biologically very different from a heap that is largely clean wood shavings with a relatively small amount of manure.
Straw, paper, hemp and wood-based bedding all bring carbon and useful structure, but woody materials contain more resistant lignin and cellulose and generally need more time to break down.
That doesn't mean the worms can't deal with them.
It means you need to give the whole biological community time.
The worms are very good.
They aren't wood chippers.
Where bedding is extremely woody, pre-composting first can make an enormous difference because fungi and microorganisms start opening up that resistant carbon before the worms take over.
One important point for horse owners: worming treatments
This is worth knowing before you start.
Some veterinary antiparasitic products are excreted in dung and remain biologically active afterwards.
Ivermectin is a good example. Controlled research with Eisenia fetida has found that ivermectin exposure can impair worm growth and reproduction at sufficient concentrations.
That does not mean manure from every recently wormed horse will kill your composting worms.
But if you're running a livery yard or stable and animals have recently been treated with ivermectin or another persistent antiparasitic product, it's sensible to know what has gone into the muck heap.
Where practical, keep recently treated manure separate for a period, follow veterinary/product guidance and, if you're uncertain, do a small worm test before committing a large population.
That's really the theme running through this whole page:
know the biology you're working with.
This is one of the practical benefits that particularly interests farmers and horse owners.
Vermicomposting doesn't make matter disappear by magic.
What happens is that worms and microorganisms metabolise organic matter. Some carbon leaves the system through respiration as carbon dioxide. Moisture changes. Coarse material is fragmented. Organic compounds are transformed and the overall material becomes more stable and considerably finer.
In research using feedlot cattle manure, successful Eisenia fetida vermicomposting reduced the original manure dry mass by about 30% while at the same time producing worm biomass and a much more stabilised end product.
Other studies also show increased organic-matter degradation when suitable worms are introduced. A 2024 experiment, for example, found that the optimal Eisenia fetida treatment increased organic-matter degradation by around 35% compared with the no-worm control in that particular green-waste system.
We don't therefore promise:
“Buy these worms and they'll halve your muck heap.”
Actual wet volume depends enormously on moisture, bedding, feedstock and management.
But biologically the direction is clear:
bulky, unstable organic matter becomes less bulky, finer and more stabilised as decomposition proceeds.
For an equestrian yard where muck storage is taking over the place, that's rather useful.
The fascinating bit about worm composting is that the worm is really only the visible member of an enormous workforce.
Bacteria and fungi are doing much of the biochemical decomposition.
The worms live amongst and feed within that microbially active material. They ingest partly decomposed organic matter together with microorganisms. They fragment it physically, pass it through their digestive system, move through the bed and continually expose new surfaces for microbial colonisation.
Modern research increasingly supports the idea that earthworms and microorganisms are partners rather than simply predator and prey. A 2025 meta-analysis found that earthworms increased bacterial abundance by about 17% and fungal abundance by about 31% on average across the studies examined.
So when we say:
“the worms are doing the work”
what we really mean is:
the worms are helping to manage an astonishing microbial workforce.
“The worm isn't the whole composting factory. It's an ecosystem engineer working in the middle of the factory.”
— Lower Blakemere Farm
Composting worms are not ordinary field worms
This distinction matters.
Earthworms occupy different ecological jobs.
Composting worms — epigeic worms
Our Farm Composting Worms contain:
Tiger/Brandling Worms — Eisenia fetida
and
Dendrobaena — Dendrobaena veneta
These are epigeic, or surface-dwelling worms.
They naturally thrive in the upper layers of rich organic material such as old manure, leaf litter and compost. Your Wiggly worms are already supplied as this mixed Tiger/Dendrobaena composting population.
Soil worms
The big Lob Worm, Lumbricus terrestris, is an anecic worm. It creates permanent deep burrows in soil and drags surface material down into them.
There are also endogeic worms, which spend much of their time feeding and moving through mineral soil.
Different worm.
Different job.
So please don't buy 20kg of composting worms and scatter them over a grass field expecting them to become Lob Worms.
Put the composting worms into the organic-material system where they belong.
Then use the finished compost to improve the conditions for the field worms that already belong in your soil.
Darwin was onto this 145 years ago
Charles Darwin spent decades studying earthworms and eventually devoted his final scientific book to them.
His conclusion remains one of our favourite worm quotes:
“The land was in fact regularly ploughed, and still continues to be thus ploughed, by earth-worms.”
— Charles Darwin, 1881
Darwin recognised that worms move, mix and transform surface material on an astonishing scale.
Modern soil science has added the microbiology to that picture, but the underlying observation remains remarkably good.
These apparently insignificant animals alter the environment around them.
More organisms in a teaspoon of soil than people on Earth
And then we get to the bit underneath the worms.
Soil isn't dirt. It is an ecosystem.
One of those facts that sounds as though someone made it up is that a teaspoon of healthy soil can contain more living organisms than there are people on Earth.
USDA Natural Resources Conservation Service uses exactly that comparison when explaining soil health and the soil food web.
Think about that for a moment.
One teaspoon.
Billions of bacteria can be living alongside fungi, protozoa, nematodes and all sorts of other organisms.
The worms are simply the bit big enough for us to see.
That's why we are so interested in composting biologically.
We're not trying to make a sterile product with an NPK number stuck on the bag.
We're trying to turn organic material into something that can feed and support a living soil system.
Hot compost first. Worms later.
This is perhaps the most important practical instruction on this page.
Don't put expensive worms into a steaming-hot muck heap.
Vermicomposting is a mesophilic process. Worms operate at moderate temperatures.
Hot composting is thermophilic and can reach temperatures of 50–70°C.
Those temperatures can be extremely useful for breaking down fresh organic matter and, if the process is properly managed, reducing pathogens and weed-seed viability.
But they are not useful if you're a worm.
Research confirms that high thermophilic temperatures inhibit Eisenia fetida vermicomposting.
As a useful farm guide:
15–25°C — lovely
25–30°C — keep an eye on it
Above around 30°C — we'd normally wait
Steaming manure — definitely wait
This is why the combination of hot composting followed by worms makes so much sense.
Heat first. Worms later.
Each does a different job.
And yes, it is entirely possible to spend £439.95 on worms and kill them remarkably quickly by putting them into 50°C manure.
We'd rather you didn't.
Bokashi first. Worms afterwards.
This is another system we use here at Lower Blakemere.
We use Bokashi Bran in our deep-litter cattle sheds.
The Bokashi starts a fermentation stage while the straw, manure and urine are underneath the cattle.
Eventually we muck out.
That material then moves into an aerobic decomposition stage.
We don't put the worms straight into strongly fermenting Bokashi material.
Freshly fermented material can be acidic and, once exposed to air, manure can begin heating.
So we let it transition.
We let it aerate.
We let it cool.
Then the worms can take over.
The sequence is:
Cattle + bedding + Bokashi → fermentation → aerobic composting → cooling → composting worms → vermicompost → soil.
There is published research specifically comparing traditional pre-composting and Bokashi pre-composting before vermicomposting, including horse manure. Both approaches successfully produced mature vermicompost in that study, supporting the idea that fermentation and worms can work very well as successive stages rather than simultaneous ones.
Worms in our Johnson-Su bioreactor
We also use composting worms as part of our Johnson-Su system here at Lower Blakemere.
The Johnson-Su bioreactor is designed to keep compost aerobic while allowing it to mature for a long period without repeated mechanical turning.
Again, the worms don't go in at the beginning.
Published Johnson-Su work describes adding Eisenia fetida after the initial heating stage has fallen below approximately 28°C. The worms then become part of that slower maturation process.
It's another good illustration of why we like stacking biological processes.
The bacteria and heat have one job.
The fungi have another.
The worms have another.
We're not asking one organism to do everything.
Worms in an IBC — one of our favourite simple systems
You absolutely don't need a huge commercial vermicomposting plant to get started.
An ordinary IBC can make a very good farm worm system.
We have worms working in an IBC at Lower Blakemere and regularly add suitable organic waste to the top.
IBC systems are particularly useful because they're:
contained,
readily available,
cheap compared with purpose-built systems,
relatively easy to keep moist,
easy to replicate,
and small enough that you can learn without gambling a year's worth of manure on your first attempt.
Farm-scale vermicomposting guidance also recommends IBC-type systems and shows how multiple units can simply be added as the operation grows.
Frequently asked questions
How do I know manure is ready for worms?
Use four simple tests.
Is it hot?
If yes, wait.
Does it stink strongly of ammonia?
If yes, wait or mix/aerate it.
Is it rotten and sulphurous?
If yes, you've probably got an oxygen problem.
Does it feel moist and earthy rather than hot, slimy or aggressive?
You're getting much closer.
And if you remain uncertain:
Do a worm test.
Take a bucket of the material.
Add a handful of worms.
Keep it shaded and moist.
Look again the next day and again after 48 hours.
If they've settled into the material, that's reassuring.
If they're all climbing the bucket looking for Hereford station, the material isn't ready.
Test with a handful before testing with £400-worth.
How much should I feed them?
There isn't a sensible universal formula.
You'll often read that a worm can eat its bodyweight in food every day.
Under very favourable conditions and with easily processed material, surprisingly high consumption rates are possible.
But farm manure isn't a laboratory diet.
Temperature varies.
Bedding varies.
Moisture varies.
Aged cattle muck is not the same thing as a heap of woody horse shavings.
So we don't promise:
10kg worms = exactly 10kg waste every day.
Instead, add manageable layers and watch how fast they're being processed.
If the previous feed is disappearing and the worms are active throughout it, add more.
If material is building up faster than they can manage it, slow down.
Let the biology set the feed rate.
Do the worms multiply?
Yes, and this is one of the loveliest parts of the system.
Once conditions are good, you'll begin finding cocoons and then tiny juvenile worms.
Eisenia fetida is a prolific composting species and populations can increase surprisingly rapidly under favourable conditions.
But again, we don't promise a fixed doubling time.
Actual population growth is affected by:
temperature,
moisture,
food,
population density,
season,
and the quality of the habitat.
The important bit is that you are establishing breeding livestock rather than repeatedly applying a consumable product.
A small, well-managed worm system can therefore become a much bigger system over time.
What can I feed Farm Composting Worms?
Suitable materials include cooled and partly decomposed:
cattle manure,
horse manure,
sheep and goat manure,
strawy bedding,
suitable stable bedding,
crop residues,
spent vegetable plants,
fruit and vegetable wastes,
coffee grounds mixed with other materials,
shredded clean cardboard and paper,
mature or partly mature compost,
and Bokashi-treated material once it has moved through fermentation, become aerobic and cooled.
Poultry manure can also be vermicomposted, but because it can be particularly nitrogen-rich, high in ammonia and salty, we'd normally blend it with carbon-rich material and pre-compost it first.
The question isn't simply:
“Is it organic?”
The question is:
“Can a worm breathe, feed and reproduce in it?”
What do worms actually produce?
The finished material is generally called vermicompost, vermicast, worm compost or worm casts.
Technically, pure worm cast is material that has actually passed through a worm.
Farm vermicompost normally contains a mixture of:
worm casts,
microbially transformed organic matter,
humified material,
fine feedstock particles,
microorganisms,
worm cocoons,
and often a few worms.
And that's absolutely fine.
What we are trying to produce isn't laboratory-grade pure worm poo.
We're trying to make excellent biologically processed organic matter.
How rich are worm casts?
This is where worm casts get talked about as “black gold”, but it is worth understanding what that actually means.
There is no universal NPK analysis for vermicompost.
A worm can't create nitrogen, phosphorus or potassium out of thin air.
What comes out depends on what went in.
Research reviews commonly report mature vermicomposts in the region of roughly:
1–3% total nitrogen
about 0.4–2.5% phosphorus
about 1.6–2.3% potassium
along with organic carbon, calcium, magnesium, sulphur, micronutrients and a substantial biological component.
A recent agricultural-waste experiment, for example, produced vermicomposts containing approximately 1.1–2.6% nitrogen, 0.48–1.21% phosphorus and 0.62–1.45% potassium depending on the feedstock.
The variation is the point.
Feedstock matters.
Horse manure won't necessarily produce the same analysis as cattle manure.
A heavily straw-based mix won't be identical to vegetable waste.
If you're producing vermicompost at meaningful commercial or farm scale, get your own finished material laboratory tested.
Then you'll know what you've actually made.
What can I do with finished vermicompost?
There are several routes.
Use it around planting
For vegetables, trees, shrubs or transplants, blend mature vermicompost into the soil or compost around the root zone rather than putting a thick layer of pure casts directly against the roots.
Research often finds useful responses when vermicompost makes up a modest proportion of the growing medium, rather than replacing the entire medium. Depending on the crop and experiment, rates from around 5–20% and upwards have been studied successfully.
For practical farm or market-garden planting, we tend to think:
a handful where the plant needs it rather than tonnes everywhere.
Top-dress
Use it around established plants or in horticultural beds.
Add it to compost or growing media
A relatively small proportion of good vermicompost can add both nutrients and biologically processed organic matter.
Put it back onto land
Larger quantities can be returned as an organic amendment, subject of course to feedstock, regulations and your nutrient-management plan.
Make an extract
This is where a small amount of very good vermicompost can potentially reach a much larger area.
Worm liquid, worm tea and worm extract are not the same thing
These names are constantly muddled together.
We think farmers are better served by knowing the difference.
1. Leachate — the liquid from the bottom of the IBC
This is simply water that has percolated through the worm bed and drained into the bottom.
It can contain soluble nutrients and microorganisms.
Extension guidance commonly suggests diluting fresh worm-bin leachate around 10 parts water to 1 part leachate for soil application.
But it is variable because you don't fully control what the water has travelled through.
If your IBC is based on animal manure, we would not use raw leachate as a foliar spray over edible crops.
Use it as a soil drench if appropriate, diluted and fresh.
2. Vermicompost extract
This is the one we particularly like.
You deliberately take mature vermicompost, put it into water and physically extract soluble compounds and microorganisms into the water.
Because you choose the starting compost, water and extraction process, you have far more control than you do with random drainage liquid.
3. Brewed or aerated worm tea
This is a longer brewing process, often involving aeration and sometimes added microbial foods such as molasses.
There is interesting research around compost and vermicompost teas, but adding readily available sugars can also stimulate undesirable microorganisms if they happen to be present.
USDA guidance specifically raises this issue with molasses and other supplemental sugars in compost teas.
For straightforward farm use, our preference is therefore:
good mature vermicompost + clean water + vigorous extraction + use it fresh.
Simple.
FREE Coir Bedding Block with every order
Every Farm Composting Worm order — 2kg, 5kg, 10kg or 20kg — includes one FREE coir bedding block.
The block expands to approximately 9 litres when water is added. Coir holds moisture while maintaining useful air space, making it an excellent starter refuge for newly delivered composting worms.
Hydrate it with roughly 3–4 litres of water, allow it to expand and mix it with your prepared mature compost or aged manure.
The coir isn't the whole bed.
It's simply somewhere safe and stable for the worms to arrive before they spread into their new home.
Live-worm delivery
These are living animals.
Please have your system prepared before they arrive and introduce them as soon as practical.
We may alter dispatch during periods of extreme heat or other weather that makes live transport unsuitable.
That's inconvenient occasionally.
Dead worms are considerably more inconvenient.
Worms Can:
Process properly prepared cattle manure.
Work particularly well with horse manure.
Reduce and stabilise organic matter.
Produce fine, biologically processed vermicompost.
Transform coarse bedding and manure into a more manageable material.
Work in IBCs.
Work in manure beds and windrows.
Join a Johnson-Su system after the hot phase.
Work beautifully as a later stage after Bokashi.
Multiply and establish a self-reproducing population.
Help you turn a manure-management problem into a soil resource.
Produce material suitable for making fresh vermicompost extracts.
Create organic amendments which, when returned to soil, can help support the wider native soil-worm community.
Worms Won't:
Survive happily in hot compost.
Fix an anaerobic slurry.
Magically dry a waterlogged muck heap.
Create N, P or K from nothing.
Guarantee a particular nutrient analysis.
Guarantee pathogen or weed-seed destruction.
Ignore unsuitable veterinary-drug residues.
Automatically process a tonne of waste just because an online chart says they should.
Replace good manure management.
Or read your spreadsheet.
More Frequently asked questions
Are these ordinary earthworms?
No.
They are specialist surface-dwelling composting worms, predominantly Eisenia fetida and Dendrobaena veneta.
How many worms are in a kilo?
Worms vary in size and age, so we sell by weight rather than count.
As a rough guide, the existing Wiggly mix is approximately 1,600–2,000 worms per kilogram, but this should be treated as an estimate rather than a guaranteed number.
Are these worms good for horse manure?
Yes.
Horse manure is a very useful vermicomposting feedstock once it has cooled and become suitable. Bedding type and veterinary treatments should also be taken into account.
Will worms reduce my muck heap?
They can reduce and stabilise the organic matter, although actual wet-volume reduction depends heavily on bedding and moisture.
Research has recorded around 30% dry-mass reduction in a cattle-manure vermicomposting system.
Can I add them to fresh manure?
Not if it is hot, strongly ammoniacal or anaerobic.
Pre-compost first.
Can I use them after Bokashi?
Yes.
Allow Bokashi-treated material to move into its aerobic decomposition stage and cool before introducing worms.
Can I put them in a Johnson-Su bioreactor?
Yes, during the cooler maturation stage rather than the initial hot stage.
Can I use them in an IBC?
Absolutely.
We do, and think it's one of the simplest ways to begin experimenting with farm-scale vermicomposting.
What moisture do they like?
Moist but well aerated — approximately the feel of a wrung-out sponge.
What temperature do they like?
Around 15–25°C is excellent territory.
Avoid hot composting temperatures.
Will they reproduce?
Yes, when food, moisture, oxygen and temperature suit them.
Do they encourage other worms in my fields?
Indirectly, yes.
These composting worms themselves belong mainly in rich surface organic matter, but the compost and organic matter they help produce can provide food and better habitat for native field earthworms.
Field research consistently shows that organic amendments such as manure and compost can support greater earthworm abundance and biomass.
Are worm casts a fertiliser?
They contain useful nutrients, but we prefer to think of mature vermicompost as a biologically processed organic soil amendment rather than simply another fertiliser.
What is typically in vermicompost?
It varies with feedstock, but reviews commonly report roughly 1–3% nitrogen, 0.4–2.5% phosphorus and 1.6–2.3% potassium, along with organic carbon, calcium, magnesium, micronutrients, humic substances and microorganisms.
Can I use it when planting?
Yes.
Blend mature vermicompost into the root zone or growing medium rather than planting directly into pure casts.
Can I make worm tea?
Yes — but distinguish between drainage leachate, deliberately made vermicompost extract and brewed compost tea.
We particularly like a fresh water extract made from good mature vermicompost.
Can I use the IBC drainage liquid on plants?
Fresh leachate can be diluted — commonly around 10 parts water to 1 part leachate — and used as a soil drench.
We would not use manure-derived raw leachate as a foliar spray on edible crops.
Can I use vermicompost extract as a foliar feed?
Research has used vermicompost-water preparations as foliar treatments, including 5%, 10% and 20% concentrations.
We'd start cautiously, filter it properly and trial a small area first.
How do I separate the worms from the finished compost?
The easiest methods are migration towards fresh food, harvesting mature compost from beneath an IBC, using light to make worms retreat into a pile, or screening.
We generally prefer migration because the worms do most of the work themselves.
What if my horses have recently been wormed?
Be aware that some antiparasitic drugs, including ivermectin, can affect earthworm growth and reproduction.
Check what treatment has been used and consider keeping recently treated manure separate or doing a small worm test first.
Will vermicomposting kill pathogens?
Don't rely on it to.
Where sanitation matters, use a properly managed hot-composting or other appropriate treatment stage before the worm stage.
The science behind this page
Worms and microorganisms
A 2025 meta-analysis found that the presence of earthworms increased bacterial and fungal abundance on average, reinforcing the idea that earthworms and soil microorganisms often act as ecological partners.
Earthworms and decomposition
A global meta-analysis found earthworm presence substantially increased plant-litter decomposition, although effects varied by ecological worm group and environment.
Horse manure
Published work demonstrates that Eisenia fetida can successfully grow and process horse-manure-based feedstocks.
Bokashi followed by worms
Research comparing conventional and Bokashi pre-composting followed by vermicomposting found that both routes could produce mature vermicompost, including from horse dung.
Vermicompost nutrients
Recent reviews describe mature vermicompost as typically containing useful nitrogen, phosphorus, potassium, organic carbon and biologically active material, with composition strongly dependent on the feedstock.
Native earthworms and organic amendments
European field research shows that manure, compost and other organic amendments can increase earthworm abundance and biomass, although tillage, soil, crop and climate also have major effects.
Vermicompost extract
Research shows that extraction conditions, particularly aeration and time, influence how nutrients and other compounds move from vermicompost into water.
Compost teas and food safety
USDA guidance cautions that adding readily available microbial foods such as molasses can increase the risk of pathogen multiplication if the original compost is contaminated.