How to Fatten up Worms in A Worm Farm

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Whether you are raising worms for compost or for fishing bait, the size of your worms is going to matter.

If you notice that your worms are on the smaller side, then that could be cause for concern as it could be an indication of an inadequate living environment, one that will need changing sooner rather than later. 

On the other hand, it could also be an indication that you simply need to be adding a little more food for them to eat. 

Whatever the case, there are a few things that you can do to ensure that your worms are the perfect size for your needs.

Why Are My Worms so Skinny?

Red worms are generally quite skinny, especially if they are young; however, if your mature worms seem to be thin, then this could be due to a few things: 

  • Your worm bin is overcrowded: Although there isn’t a general rule of thumb regarding how many composting worms you can have in your worm farm, if your red wigglers begin to appear slightly skinny, then it could be that there are too many of them for one bin.

The more red worms there are, the less each worm gets to eat from your kitchen scape.

Moreover, having too many compost worms in one bin can also create problems for their breathing as they will not be able to derive the same amount of oxygen from the soil as they usually would. 

  • Your red wigglers are being underfed: Not having enough to eat is not always directly connected to overcrowding in the worm bin.

It could just be that your red wiggler worms need some more food on a daily basis.

If you do not produce enough food scraps for the worms that you have, then you will have to buy some extra worm food for them. 

  • Your compost worms are dehydrated: The moisture levels in your bin are essential for the survival of your red wiggler worms.

Since worms breathe through their skin, they need to constantly be in moisture in order to breathe.

Moreover, A worm’s skin is very delicate and therefore needs the moisture in order to be able to move safely through the soil.

That’s why a bin that is too dry will leave your worms dehydrated and could therefore reduce their size. 

How Do You Fatten up Worms?

In order to fatten up your red worms, you can start by reducing the worm population in the bin.

This could simply mean getting a second bin to store the rest of your earthworms, or giving some away, releasing them in the garden, etc.

This will ensure that the worms in each bin will have easier access to the food; just remember to add enough food for each bin!  

Then, you should start feeding them foodstuffs that are easy for them to consume.

That includes large amounts of fruit and vegetable waste (melon rinds, apple cores, and other table scraps (such as coffee grounds), and less dry foodstuffs (such as dry leaves, grass clippings, powdered eggshells, etc.). 

Specialist products such as Purina Worm Chow may work well, too.

Finally, you will need to see the bedding in your worm bin nice and moist.

If the bedding that you are using is dry or dries out quickly, then you can sprinkle some water over it with a spray bottle a few times a week, making sure to mix the fresh bedding and the water well in the worm bow with a mixing spoon, or with your hands. 

What to Feed Worms to Make Them Big?

If your worms needs fattening up, then feeding them the right stuff is key.

You can start by giving them your fresh vegetable scraps and enough to keep them all going.

The composting worms’ diet should have plenty of variety, even in basic worm feed.

If, however, you have found that even the scraps that you have not been doing the trick, then it may be time to try some specialist produce.

You could start by using Purina worm chow.

All you need to do is mix it in with the other foods, and soon enough will be your fatter worms’ favorite food. 

organic food as worm feed

Do Worm Farmers Feed Their Worms Anything Special to Help Growth?

When it comes to worm farming, generally speaking, the bigger the worms, the better.

The bigger they are, the more they can feed on, the most compost they can make.

For other kinds of people who raise worms, for example those who do it to make fishing bait, the worms’ size matters just as much, as the bigger they are, the better they will work as fishing bait. 

With that in mind, some farmers use corn flour, or corn meal in their worm farming as a fattener supplement ingredients to help fatten their worms.

However, this has to be done carefully to ensure that the worms are able to eat just as much fresh and organic matter as they need. 

Some also add fish to their worm bins due to their great fats and nutrients, however, do be careful not to add any fish with spices on, and you might want to add a little rather than a lot, as this can lead to quite the bad smell (which could attract other animals). 

Things to Be Careful of

Your composting worms diet is essential for their survival, as is the case with all living things.

However, since their diet is made of organic decaying matter, some assume that that means that their worms can eat anything, but that is not the case. 

When fattening your worms, it is essential to avoid any dangerous food such as dairy products (such as yoghurts, cheese, powdered whole milk, etc.) or citrus fruits which are difficult for the fishing worms to digest and could end up killing them. 

You will find that even if it is organic, overfeeding them protein can also lead to poisoning and death.

So, be picky about the kitchen scraps you add to your worm bed.


Whether you have European night crawlers, African night crawlers or red wigglers, raising worms is relatively easy and can be a very fruitful endeavour.

It simply takes a little time getting to know how to feed your worms the best things for them and what the best worm bedding is for you to get the best results possible.