Introduction
For those who are keen on learning more about composting, you might be wondering about the different composting techniques.
If so, have you considered composting with mealworms? Vermicomposting (composting with worms) is growing increasingly popular, and you might be wondering whether you can use mealworms for the same process.
Mealworms aren’t really worms, and they aren’t suitable for vermicomposting like red wigglers are.
They will, however, help to break down dead organic matter in your compost pile, at least while they are “worms.”
Their frass (poop) is nutritious and useful to plants, and they will increase the speed at which food is broken down. However, once they become beetles, you may find they are not very useful.

Will Mealworms Help My Compost Bin?
Mealworms in your outdoor compost are nothing to worry about, and they will actually help to break up the compost and turn it into something useful – frass, which you can use to fertilize and feed your plants.
Like worms, what they excrete is rich and great for the garden, although may not be quite as rich as the produce of red wigglers and other compost worms.
The mealworms will mostly feed on dead and decaying matter, which is exactly what you want the things in your compost bin to eat.
They tend to go for food scraps, and will eat almost anything, including sometimes each other, without discrimination.
If the worms find your compost bin to their liking, they will probably start to grow and reproduce in there. You may see their pupae, which will do nothing for the compost, and their beetles, which will probably leave.
The beetles won’t help the compost bin, so you can ignore them. They are just interested in launching the next generation.
The best place to find mealworms outdoors is your compost pile, as here they are actually being useful and not harming any living plants by eating their roots.
However, if you are trying to get a new compost pile active and working efficiently, you might be better off purchasing compost worms to add, rather than putting in mealworms.
If you already have mealworms, feel free to try adding some, and if they turn up on their own, that shouldn’t cause any issues. However, they aren’t necessarily as effective at creating compost as compost worms.
Mealworms may also find an outdoor compost heap too wet for them – and if they don’t, it could be a sign your compost is too dry to be working effectively.
Make sure you check it’s wet enough to be decomposing, as mealworms tend to prefer very dry environments, so their presence could indicate a problem.

Can I Use Mealworms In An Indoor Compost Bin?
You can, but with some caveats. Mealworms need to be in a smooth container with high sides, or they will escape and get all over your house.
You will also end up with beetles that do not have any particular use after a while.
These should be removed, but you will have to work out what to do with them.
You could feed them to the birds in your garden (if you have one).
You need to make sure that your mealworms in the house don’t get too wet or too hot.
While outdoor mealworms will just leave if the conditions don’t suit them, indoor ones don’t have that option, and you wouldn’t want them to take it if they did.
That means keeping an eye on the temperature and humidity levels, and making sure your mealworms are comfortable, fed, and happy.
You will also need to remove any mold from the box, as they hate wet conditions and will quickly die if mold is allowed to spread.
Adding shredded paper and eggboxes to the mealworm’s container will help to keep them dry, stop them from getting squashed, and give them another source of food (though they tend to eat paper products fairly slowly).

What Are The Pros Of Composting With Mealworms?
- Breeding mealworms is a great way to have a ready supply for pets that enjoy them (e.g. chickens, lizards, etc.).
- Mealworms break food down quickly and effectively (although you will need to be careful about feeding them wet foods such as melons; this tends to make their environments too wet).
- Mealworm poop can be used to fertilize plants.
- Mealworm populations will expand fairly quickly, as they usually breed fast, so you don’t need to get lots of mealworms in order to experiment with mealworm composting; you just need the patience to let their population grow.
- Mealworms are cheap to feed, enjoying pretty much any organic scrap you give them.
- They are not great escape artists, so you can keep them indoors fairly easily.
- They are harmless and pose no threats to people or pets.
What Are The Cons Of Composting With Mealworms?
- The waste they produce may not be as good as the waste produced by red wigglers and other composting worms.
- You will probably need to supplement their food scraps with bran or other cereals, as these are their main diet.
- They can be fussy about their conditions and won’t thrive if the container is too wet or too hot.
- Once the worms pupate, they become useless to you.
- The beetles might be better at escaping and could get into the house. They are harmless and can’t fly, but you still might not like this idea very much.
- They may not break down food as fast as real composting worms, although they will generally get through the things they like fairly quickly.
- Mealworms in outdoor compost heaps might attract rats or other vermin that want to feed on them.
Summary
Mealworm composting could be an interesting experiment to undertake, and you may get some valuable plant food out of doing it.
You will probably find that it is not as effective or easy as vermicomposting in the traditional manner, but it’s a good option to explore if you want to breed mealworms to feed to your pets.
If mealworms have found their way into your outdoor compost independently, let them keep at it – they will only be helping the natural processes that turn the waste into something useful!