Where Do Pot Worms Come From – Compost Garden Soil Has Worms


By: Anne Baley

If you’ve added materials that change the pH balance in your compost pile or if rain showers have made it much wetter than usual, you might notice a large collection of white, small, thread-like worms working their way through the heap. These are not baby red wigglers as you might think, but rather a different breed of worm known as the pot worm. Let’s learn more about pot worms in compost.

What are Pot Worms?

If you’re wondering what pot worms are, they’re simply another organism that eats waste and gives aeration to the soil or compost around it. White worms in compost aren’t directly a danger to anything in your bin, but they do thrive on conditions that the red wigglers don’t like.

If your compost pile is completely infested with pot worms and you want to lower their population, you’ll have to change the conditions of the compost itself. Finding pot worms in compost means the other beneficial worms aren’t doing as well as they should, so changing the conditions of the compost itself can change the worm population.

Where Do Pot Worms Come From?

All healthy garden soil has worms, but most gardeners are only familiar with the common red wiggler worm. So where do pot worms come from? They were there all along, but only a tiny fraction of what you see during an infestation. Once the conditions for pot worms gets hospitable, they multiply in alarming amounts. They won’t directly harm any other worms in the compost, but what is comfortable for a pot worm is not as good for common wiggler worms.

Dry out the compost heap by turning the pile frequently, skipping watering for a week or so and covering it with a tarp when rain threatens. Even the moistest compost will begin to dry out after a few days of this treatment.

Change the pH balance of the compost by adding some lime or phosphorus to the pile. Sprinkle wood ashes in among the compost materials, add some powdered lime (like that made for lining baseball fields) or crush up eggshells into a fine powder and sprinkle them all through the compost. The pot worm population should decline immediately.

If you’re looking for a temporary fix until the other conditions are met, soak a piece of stale bread in some milk and lay it on the compost pile. The worms will pile onto the bread, which can then be removed and discarded.

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I have bugs (worms/maggots/pot worms/mites/flies/slugs/snails/ants) in my compost. What should I do?

Worms are a welcome friend in your compost bin. Not only do they breakdown organic material but they also keep the bacterial population balanced. This will assist you in maintaining an efficient compost process.

Generally, the type of worm that will naturally make its way from your garden into your compost bin is an earthworm. Earthworms are different to the red wriggler and tiger varieties that you may have seen in a worm farm. While still useful in your compost bin, they are a little more sensitive to heat, cold and moisture so you may find that they leave the compost bin in response to smaller changes in their environment.

Often confused with blow fly maggots, black soldier fly larvae are: bigger, browner and more segmented. They help break down compost faster, and similar to worms create a nutrient-rich compost. But, they aren’t for everyone.

There’s no easy way to remove them. Just stir more often, add more garden scraps, and they’ll leave in a few weeks.

Blow fly and house fly maggots

Eek - maggots can be a little unsightly but don’t worry, they won’t do any harm. Often confused with black soldier fly larvae, blow fly and house fly maggots are: smaller, lighter in colour, do not darken with age and are less segmented. The presence of maggots suggests that meat or dairy are present. While meat and dairy can be added to cold compost in small amounts, if they are added in large amounts or don’t breakdown quickly enough, blow flies will be attracted by the smell and lay eggs.

To get rid of blow fly maggots, place a piece of bread soaked in milk inside the compost bin overnight. This will attract the maggots, then just pull them all out in the morning.

Don't worry, your compost hasn't been invaded by alien worms. Pot worms are very small, white worms. Often confused with baby red wriggler worms, pot worms are: Only white in colour and do not grow larger than a baby red wriggler worm.

Pot worms prefer a moist, acidic environment. While they won’t harm other worm species and are efficient at aerating soil and breaking down organic material, they may indicate some imbalances in your compost bin.

To reduce a pot worm population, place a piece of bread soaked in milk inside the compost bin overnight. This will attract the pot worms, then just pull them all out in the morning. You can also adjust the moisture and pH levels by adding more brown matter to your compost bin.

While a little pesky, these tiny flies help to decompose organic material in your compost bin.

If their population is getting too high, try the following. While there is no quick fix, this will work to reduce their population as soon as possible!

  • Make sure to keep your lid firmly on the compost bin between additions of organic material
  • After each addition of organic material, cover your compost with a layer of carbon-rich material

A large mite population commonly indicates that your compost bin is too moist. This may be caused by overwatering, poor drainage or an imbalance between green and brown matter.

To reduce the mite population, try reducing the moisture level in your compost bin. Add brown matter and aerate the compost bin regularly, and minimise the addition of water until the mite population is reduced.

Slugs and snails are masters at decomposing organic matter and help break down organic matter in the compost bin. While there is often concern for them laying and spreading their eggs through compost, the eggs will likely be eaten or decompose in the compost.

If they begin taking over, do not add chemical baits. Slugs and snails will generally congregate on the surface of the compost bin. You can try picking them off as well as increasing the amount of brown matter in your compost as slugs and snails prefer a soggier environment.

The presence of ants indicates that your compost bin is dry. Either decrease the amount of dry matter going into your bin or alternatively, you can give your compost a quick hose when you're doing the garden!

Cockroaches hide in warm, dry, still patches. Soak your compost with a hose, then turn and toss thoroughly using your Revolver. Only add garden scraps when you 'Food, Stir, Garden' to avoid dry patches forming.


1 Answer 1

I can't tell if they are maggots rather than worms - flies would be delighted to lay their eggs on that sort of waste laying on the surface, and I'm not surprised it smells.

In a proper compost bin or heap, what keeps it from being smelly is the right mix of greens (Nitrogen) to browns (Carbon). The correct ratio is around 25 to 30 parts carbon to 1 part nitrogen, or roughly two thirds carbon to one third nitrogen. What you've dumped on top of the soil won't contain any browns (carbon) by the sound of it, and when you say kitchen scraps, hopefully that just means things like vegetable and fruit peelings or scraps of vegetative origin, and not meat, fish or other types of scraps.


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Composting worms speeds up the composting process. New worm bin owners tend to make mistakes. Once you get the hang of vermicomposting, you will love it! Reducing trash, saving the earth, and creating free fertilizer makes worm composting worthwhile. Your household might even adopt the worms as members of the family! Watch out for these five common mistakes.

Mistake #1: Overfeeding

Enthusiastic worm bin owners toss every available scrap into the bin. The worms cannot keep up. The bin starts to smell terrible!

In theory, worms can eat their weight in scraps per day. However, that number might be lower, depending on air temperature and other factors. A fool-proof method is to feed them every 2 to 3 days. Be conservative in the quantity. Soon, you will get a feeling for how much food they can handle. They should start eating one feeding before you add another. An entire feeding should be completely gone in 1 to 2 weeks.

Mistake #2: Wrong Foods

Worms need a healthy diet in small pieces. Whole cabbages and watermelon rind halves will take too long to break down. Processed food, meat scraps, salty snacks, spicy foods, oily sauces, yogurt, pineapple, and bushels of tomatoes can spoil the bin. Most non-food items are also bad ideas.

The ideal diet for composting worms is non-acidic fruit and vegetable scraps. Grains, bread, coffee grounds, tea bags, and pasta are also fair game. Aged grass clippings, hair, and herbivore animal manure are compostable. Add shredded black-ink newsprint in moderation. Torn or shredded brown corrugated cardboard is acceptable. Clean, crushed eggshells add grit and calcium. All items should be small. Larger items should be cut up or run through a food processor. Smaller pieces break down faster. This reduces odor and discourages pests.

Mistake #3: Too Wet or Too Dry Composting Bedding

The over-enthusiastic worm bin owner pours gallons of water on their worms. The negligent owner lets the bin dry out. Too wet, and the bin becomes stinky and the worms might drown. Too dry, and the worms dehydrate, cannot breathe, and can’t tunnel effectively.
The easiest way to check worm bin moisture levels is by picking up a handful. Squeeze it. If water comes out, it’s too wet. Worm bin bedding should have the feeling of a wrung-out sponge.

See our instructions for drying out a wet worm bin. Also find out how to keep the bin moist.

Mistake #4: Forget to Harvest Worm Castings

Avid gardeners eagerly look forward to removing finished compost from their worm bin. Fresh “black gold” is the best organic fertilizer to make plants grow. Gardeners mark the days until the worm castings are ready for harvesting.

However, non-gardeners typically focus on reducing trash and odor. For them, the worm castings are a side-effect. Their worm bin eventually fills up with worm castings. Adding more trays or getting a larger bin puts off the inevitable.

Harvesting finished compost means separating worm castings from the worms. You will leave bedding behind for the worms to live in. Using a screen should only take 30 to 60 minutes. Making mounds takes a day, mostly waiting time. Tray-based composting bins might only take 10 minutes.

  • at the start and end of the growing season
  • whenever it is getting full
  • as needed, if the worms have been in the bin for at least three months and there are extra worm castings inside

If you have more “black gold” than you need, donate it to a local gardening project or neighbor.

Mistake #5: Too Hot or Too Cold

Just like people, composting worms have an ideal temperature range. The worm bin and bedding help regulate the temperature. When the air temperature is below 54 degrees Fahrenheit, worms slow down. Below freezing, they can die. Above 84 degrees can cook the worms.

Do you live in a climate that has temperature extremes? See our tips for keeping composting worms cool in summer and warm in winter. Bin location is the primary issue. You can mitigate some of the temperature hazards using ice, bin blankets, insulation, relocation, and moisture regulation.

At Uncle Jim’s Worm Farm, we offer expert information about managing your vermicomposting bin. Peruse our blog, check out our product descriptions, and read our Frequently Asked Questions. We are the #1 supplier of composting worms in the USA.


White Worms (Pot Worms) In Worm Composting

“Hi there, I started up a worm farm about 3 months ago. It is doing very well, but has lots of tiny white worms in it. They even seem to be living in the fluid which comes from the bin. Are these worms bad for either the system or the garden? If so, how do I get rid of them? I read one website saying to add garden lime, and another saying not to. I have added crushed egg shells but it doesn’t seem to have changed anything. Thanks,”

Those worms are almost certainly ‘White Worms’ – aka ‘Pot Worms’. They are members of the family Enchytraeidae, and are actually a small relative of the other ‘earthworms’ (including the composting species). They are often associated with development of acidic conditions – commonly brought about by over-feeding.

My first experience with them was back when I set up my very first worm bin. Not really knowing what I was doing, I added a BIG clump of white rice to my bin, assuming it would be consumed by the Red Worms. It ended up turning into an anaerobic mess (basically fermenting), and one of the side effects was a White Worm population explosion. They were EVERYWHERE (in the bin), and the rice itself was loaded with them.

White Worms are actually widely used as a fish food. Interestly enough, one of the suggested techniques for raising them involves soaking pieces of bread in milk and feeding it to them. You definitely don’t need to worry about the worms themselves harming your wigglers, but the conditions that brought about their population increase MAY be cause for concern.

I personally prefer not to add lime as a means of combating acidic conditions. Believe it or not, Red Worms actually prefer a somewhat acidic environment – much like that found in outdoor compost/refuse heaps.

By trying to counter-balance your acidic conditions, you will very likely shock the system, potentially causing more harm than good. Adding a little lime (or crushed egg shells etc) every now and again before problems arise is probably a better way to keep your bin buffered again serious pH swings.

In your particular case, I would personally recommend removing any excess food material in the bin and adding a lot of dry bedding to help wick up excess moisture – this should definitely help to at least get rid of all the White Worms on the lid and sides of your bin, and should get you on the right track in terms of reducing their population size down to a normal level.


Earthworms eat a large variety of organic matter. They also eat small microorganisms found all around us. Earthworms are considered omnivorous but, In a book named “In Earthworms” written by Sims and Gerard in 1985 they say it’s better to describe them as detritivores because they prefer to eat decaying animals and plant matter.

What type of plant matter? Well, Above ground worms will eat anything from dead grass to the leaves that fall from the trees. They will also consume various types of fruits, vegetables, and wild berries. Bellow ground they will feast on fungi, bacteria, and algae. Popular fungi that have been reported to be a favorite of some earthworm species are called mycorrhizal. It grows on the roots of various trees and plant species.

Not all species of earthworm, of which there are over 6000! eat soil for nutrients, But some do. These are classified as geophagous (eating of soil).

In the UK, for example, there are 4 classifications of earthworms. This includes all sorts of species, But in general identifies how they live and what food they eat.

Composting EarthwormsGenerally seen when first starting to compost a new set up garbage or manure. They do the heavy lifting in the beginning of the decomposition process.
Endogeics EarthwormsA general worm, It’s often found in soils very high in organic matter.
Anecic EarthwormsThis category actually brings food back to its den/burrow. It helps distribute nutrients.
Epigeic EarthwormsThey call rotting logs and decaying plants home. Often eating any organic matter that’s mostly decayed.

How do earthworms eat?

Ever wonder how earthworms eat? It’s really interesting!

Earthworms have no teeth, In fact, they swallow their food whole! They have a little flap that sort of act’s like lips which pushed and directs their food into the mouth hole. After that, the throat muscle takes hold, lubes it up with saliva, and slowly starts pushing it down the earthworms esophagus.

At the end of the esophagus, there is a small space called a crop. This is where food will remain until it’s ready to reach the gizzards, where it is ground up very fine until it’s passed onto the intestines to be absorbed and broken down. What the worm doesn’t use for energy is expelled out of the rear of the worm (anus). This super fertile nutrition-packed poop is called worm castings. Plant’s love this stuff.

What do earthworms drink?

Earthworms don’t drink like you or me and fluffy the cat. They absorb liquids from the soil with their skin. On that same note, Earthworms don’t breath like we do either. They breath by absorbing oxygen from the liquid and soil around their body. They can’t do this is they are dried out, tho. So it’s vital a worm always stays a bit moist.

How much can earthworms eat

Worms eat between half and 3/4 of their body weight in food every single day. So it varies based on worm species, size, and weight. If you are thinking of adding worms to your compost bin and don’t want to overfeed them, then a good rule of thumb is 1 pound of worms for every 1/2 pound of scrap or refuse every day.

It’ doesn’t seem like much but it really does add up. That’s 3 and a half pounds of food a week!

It’s important not to put in foods that won’t be consumed after a couple days. Things like meat decompose and turn the soils bad for some time, and this will hurt or even kill your worms.


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