What Do Worms Eat? EVERYTHING You Need to Know About Feeding Earthworms

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There are lots of foods that earthworms eat. They will eat just about anything (but that doesn’t always mean they SHOULD eat it) and they are not very picky eaters! 

But what do worms eat in particular and what should you feed them?

Simply put, if it is decomposing, the worm can fit the food in its mouth, and it does not affect the pH of your bin too much, they can eat it. 

Worm Food You Should Be Feeding Your Earthworms For the Best Castings

If you’re in a rush, here’s a small list of foods that worms eat and generally thrive on: 

  • Vegetable scraps/food scraps
  • Vegetable peels
  • Most farm animal manures, including sheep, cow and horse manure.
  • Most fruits (avoid too much citrus)
  • Most cereals
  • Most grains
  • Coffee grounds
  • Egg shells (crushed into a fine powder)
  • Bread (moldy is fine)
  • Tea bags
  • Newspaper/Shredded Paper
  • Cardboard
  • Leaves (watch out for poisonous plants)

But there is so much more to consider when it comes to worm food and what, when and why you should put feed into your worm farm or bin.

Things to Consider when Feeding Your Composting Worms

It’s not as simple as finding the best worm food for your composting worms.

Here are some other things to consider when putting food into your compost bin to make sure it maintains a healthy environment for our wriggly friends:

Keep the Moisture in Your Worm Bin Optimal

The most important thing for your worms is that they are in the perfect environment.

Their environment needs to be moist in order for them to survive!

As you know, worms breathe through their skin, so being in dry soil simply won’t do.

Unless the worm bin is moist at all times, your worms run the risk of suffocating and dying.

Moreover the moisture helps to make them moving about in their bin far easier.

They have very fragile skin, so the moisture makes it a lot easier and more comfortable for them to move about in the bin.

However, if the bin is too moist, then it will not be good for the compost, nor the worms.

That is why you need to be careful with the food that you feed to them.

If it is very dry food, then add some water to the bin and mix it up, to ensure that the whole bin is perfectly moist.

On the other hand, if the foods that you are adding are rich in water (such as cucumbers, tomatoes, etc.), then consider adding some bedding to the worm bin, to help soak up some of the moisture.

How Much Can Worms Eat in a Day?

As a general rule, worms can eat around half their own weight each day.

Some sources say they can eat their own body weight daily, but I’d recommend starting out on the conservative end to avoid overfeeding and food rotting in your farm.

This makes calculating how much you should feed your worms relatively easy.

Especially, if you have purchased your worms from a worm farm.

For example, if you have bought 1/2 a pound of worms, then your worms should eat around a 1/4 pound of food everyday – approximately half their body weight.

There are other factors that can affect this, like your compost bin environment and the health of your compost worms (more help with this further down)

Can Worms Eat too Much Food?

Worms won’t overfeed themselves and can regulate how much they eat, but putting too much food into your worm bin can still cause huge problems for your worms and your worm compost bin.

If you are putting more feed into your bin than your worms can consume, then you could run into some of the following problems:

Nasty Odors and Rotting

A sure sign that you’re feeding your worm buddies too much is a nasty smell coming from your bin.

Worms will want to eat their food before it is over-rotten and if they can’t, you’re inevitably going to get the nasty-smelling odors from the bacteria that comes with it.

Which also leads to…

Flies and Other Pests

It’s not the end of the world if your worm bin is shared by other bugs and insects that aren’t harmful to your worms – in fact, that’s quite normal and healthy.

But if you’re experiencing a sudden rise in fruit flies buzzing around your bin – or worse – rodents, it’s safe to say that’s something you or your worms are not going to want.

And if you’re doing your vermicomposting indoors, then I hope you live alone because you might find yourself living alone without a choice if there’s a constant offensive smell around!

Not to mention unwanted animals, insects and other pests.

The flies may not be a problem if your vermicomposting activities take place in your garden or outdoors in the ground, but even then, it’s not healthy for your worms because…

Overfeeding Can Create Too Much Moisture

Worms love fruits and vegetables! What are fruit and vegetables mostly made up of? Water.

Fruit and vegetables contain anywhere between 75% and 96% water, depending on which one.

The higher the water content, the more the worms seem to love the scraps.

Keep the high water fruits and vegetables to a small amount and monitor moisture levels.

You can always increase the quantity if all goes well.

What Not to Feed Worms

There are certain greasy, salty, acidic and spicy foods, earthworms may purposely avoid and even appear to escape from. 

While your red wiggler worms (or whichever compost worms you are using for vermicomposting) may eat these foods, they carry with them some amount of risk – either to your worms or to the environment which they do their work.

The foods not to feed worms or generally avoid are:

  • Citrus fruit peels
  • certain acidic vegetables
  • feces (read more about worms eating poop)
  • malt grounds
  • newspapers
  • fallen leaves
  • commercial cereals
  • meats
  • dairy products
  • spicy foods
  • cooking oils
  • salty or salted foods (may burn your worms skin!)

Before every vermicomposter who feeds their worms these foods get angry; I’m not saying that worms can’t and shouldn’t eat them.

I’m saying that you should be wary of feeding your worms too much of these foods and keep an eye on the environment and pH levels of your farm or worm bin while doing so. 

Many of these foods may be fine in small quantities.

The organic waste produced by many light processing plants such as wood chips and mushroom sticks can also be used as food for earthworms.

Although earthworms can eat raw/cooked meat, it is generally not encouraged to feed meat and dairy products. 

It can affect the soil quality, and can attract nasty odors and other insects or pests like flies or worse. 

What Do Worms Like to Eat Most?

Earthworms especially like to eat moist, sweet fruits such as watermelon and mango. 

It should be noted that some foods need to ferment and cool for a few days in advance before being fed to your worms, such as animal feces (which may raise the temperature of your worm bin if given fresh). 

The high temperatures of feces may cause your earthworms to try to escape from your farm or worm bin in the process of their environment heating up.

Generally, the feces fed to earthworms are cow, sheep and pig manure, but most manures tend to work well.

NOTE: Do not add dog feces for your worms to eat if the dog is undergoing any form of treatment or medication. Especially, if your dog is being treated with dewormers if they are carrying worms.

This kind of earthworm food does not need to wait for decay (but you should wait for it to cool) and is easily absorbed by earthworms. 

As long as it is balanced out by adding appropriate high carbon materials such as straw and wood chips, it makes for excellent earthworm feed to produce high-quality earthworm castings.

My Worm Feed Experiment

I did a simple experiment.

I prepared 5 plastic square basins, each split up by cardboard and divided into 3 parts. Nutrient-free soil was placed inside.

After that, about 30 adult night worms were put in to each section to adapt for 3 days before adding any food.

Then, various foods were added to each section and we waited another 2-3 days to say how the worms did with each feed.

For the earthworm food, I used: 

  • thick paper
  • dead leaves and decaying plant matter
  • coconut coir
  • oatmeal
  • pineapple
  • banana
  • watermelon
  • mango
  • papaya
  • sheep manure
  • corn
  • sweet potato leaves
  • vegetable gall
  • cabbage
  • and small maize 

Let’s see the result! There are some things that haven’t changed.

  • These are watermelons, bananas and pineapples here. It was taken shortly after the release.
pineapple banana and watermelon worm food
  • This is 1-2 days after being eaten by the earthworms and most foods have been almost completely decomposed. 
pineapple, banana and watermelon eaten by earthworms
  • Especially the watermelon, only has a thin layer of skin left. Bananas are a bit slower, surprisingly. There are probably too many pineapple skins, but the earthworms seem to love it. In the next few days, only a little bit of perishable rind was left on the pineapple. 
  • Finally, there was a thick pile of worm feces (called castings) on the soil, which is great as this was our goal from the start. 
  • The cauliflower and cabbage were slow to decay. Maize was particularly slow. They didn’t seem to eat very much, but I still found some worm castings when it came time to harvest.
worms eat feces papaya and mango

Sheep manure was decomposed at a moderate rate.

These are common vegetables sourced locally in Malaysia. Vegetable gall, cabbage, and small corn are used here.

TIP: Put any large food scraps through a food processor to make them easier for your worms to eat. Some soft foods like watermelon flesh won’t need this extra step.

But it will make a big difference in making hard foods easier for your worms to process due to the decreased surface area of the food scraps. Remember, worms don’t have teeth, so any help you can give them is a good idea.

If worms aren’t composting your foods faster than they are decomposing and rotting, you could be in for a nasty smell or a surprise visit from unwanted pests.

  • This plastic bucket contains mango, papaya, and sheep dung.

These fruits were not so fast to break down. Compared to watermelon and pineapple, these two are slightly slower. 

  • This is the slag of mushroom, which is also called a “mushroom block”. I crushed them and put them in this box to feed the Earthworms. 
  • This is coconut shell took a long time to break them into such a fine package.

One thing worth mentioning is that mushroom blocks are surprisingly fast to decompose and digest for the earthworms. 

As far as I know, it’s because it uses fermented organic matter and sawdust to add fungi, so if you want to try it, grab yourself a mushroom block.

Others like coconut coir, dead leaves, paper skins and oatmeal are relatively slow to decompose and are often used as bedding, as well as food. Which makes sense.  

Although some worm castings can be found in these 2-3 weeks, it generally takes longer, unless the food is decomposing already when you put it in your worm bin. 

What Do Worms Eat blog post image

Chicken manure

If you use chicken manure instead, you must pay attention to the pH value.

Chicken manure is acidic, so you can add some wood chips or lime powder until your bins pH is around 7 before it is eaten by earthworms. 

Cow manure is generally more preferable.

Coffee Grounds

Contrary to popular belief, coffee grounds are pretty close to being pH neutral (between 6.6-6.8pH normally). 

Coffee itself is acidic when made to drink, but the grounds are actually not. 

This is why some people get confused when they see how much worms love coffee grounds. Well, now you know. They’re not acidic.

To prevent your earthworms from escaping, you should make the proper preparations before feeding.

Here I discuss 5 reasons why earthworms escape.

What is Carbon-to-Nitrogen Ratio of Worm Food and Why is it Important?

Some of the foods that we put in our worm bins are very high in nitrogen.

Sadly, an environment that has too high a nitrogen level is unsuitable for worms and can be very dangerous for them.

Therefore, we add bedding that is lower in nitrogen and higher in carbon, to help to balance out the environment, making it more stable for the worms.

It is important to always ensure that there is enough bedding, as foods tend to release more moisture and more nitrogen as they decompose.

Therefore, the longer they are in the bin, the more you are going to need good bedding!

A good rule of thumb is to keep twenty five to thirty parts of carbon to about one part of nitrogen in your worm bin.

To achieve this, generally feeding your worms an equal mix of green and brown foods is helpful.

Green foods: are the obvious; vegetables, dead plant matter, fruit peels or rinds. These are a bit higher in nitrogen, which is needed for worms to grow.

Brown foods: Is your food waste (and often not traditional human food!) that is high in carbon and carbohydrates which your worms eat and balances out the nitrogen.

Things like egg shells, shredded paper and cardboard.

What Food Makes Earthworms Grow Fastest?

If you give them what they love, they will grow super-fast. 

The little experiment I did above found that in addition to feces, earthworms love to eat sweet fruits and mushroom block, so in addition to their staple foods, you can also give them these kind of foods – consider these food scraps dessert for your worm farm . 

Simply put – if you increase the nutrient intake of earthworms. Earthworms will grow bigger and better.

Watching this video, the earthworm uses its strong mouth to pull the banana in.

If you were wondering, do worms have mouths <– I explain here how the earthworms mouth works. 

Do Earthworms Eat Dirt?

Strictly speaking, yes earthworms do eat soil. 

But they eat the decomposing substances contained in the soil together, and then after absorption through the intestines, the nutrients are separated from the soil and output as feces to become worm castings or earthworm soil (whatever you want to call it).

We have a post dedicated to the question do worms eat dirt if you’re interested.

Do Worms Need to Drink Water? (And How They Consume it)

Worms do not drink water through their mouths as we do, however, they do need water constantly.

Worms breathe through their skin, and they consume the water in the dirt via said skin.

That is one of the reasons why they always need a moist environment in order to thrive.

Sadly, if they remain in a completely dry area for too long, then the worms will suffocate and die.

That being said, being in a completely wet environment is also bad for them as they cannot control the amount of water around them, and the worms may drown or try to escape.

How Do Worms Find and Break Down Food? 

Earthworms do not hunt down their food as most creatures do.

Instead, it appears as though they move about aimlessly, making their way through their food.

However, that is not necessarily the case.

In fact, worms use what are called ‘chemoreceptors’ to detect things around them, including their food, and other animals.

These receptors cover their bodies, and it is even believed that they may be able to taste through them, too.

What Do Baby Worms Eat?

It may sometimes seem as though you should cut the food up extra small for the baby worms, and even try to hand feed them yourself, however, that is not the case.

Baby worms eat the exact same way as adult worms.

That is to say that they will feed on the decaying matter in the worm bin, in its tiny form in the soil.

Feed them as frequently as necessary, by keeping an eye on the food in your bin, and ensure that there is enough food in the bin for them all to be able to eat comfortably, and so that the baby worms can develop well.

Try to place a wide variety of foods in the bin, to ensure that the babies especially get all of the nutrients that they need to develop healthily.

Summary of What Worms Eat and What to Feed Worms

As animals go, worms are pretty easy to please, and to take care of.

It may sound very specific and somewhat scientific the way that you need to feed them and take care of them, however, worms are actually very simple to keep.

They are far simpler than humans in that, when they’re hungry, they move more and eat, when they’re satisfied, they move less as this study shows

It’s one reason why worm composting is so popular – and why worm farms are becoming more and more commonplace.

As such, a balanced worm’s diet of organic material – providing you are careful with what’s in your food waste – will be ideal.

Once you get used to your worms’ feed and needs, their ideal environment, and their own favorite foods, it will be so easy to keep them happy and healthy.

You’ll find yourself quickly being able to recognize the perfect bin for them just by seeing the shade of the soil, or feeling it. 

You will also come to notice that when feeding worms, they definitely have tastes and eat foods with more vigor than others.

Some of the foods will go down far quicker than others, too.

Having a worm bin is obviously a great way of doing your part for the environment, but it is also a great way of getting to know these little creatures better, and witnessing their own personalities.

Appetite control: What we can learn from how worms eat – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3544365/