Do Worms Eat Bread? (Even if it’s Moldy?)

Worms eat a variety of different things – your average worm in the wild can pick and choose its diet, but what about composting worms? What food scraps can we throw into our worm bins for them to eat – and do worms eat bread?

Yes, worms will eat bread. It may not always be the most desired food for worms, nor the healthiest addition to their diet. However, it does contain natural ingredients, and it’s one of the most commonly wasted food scraps. So – you can put it to good use and feed it to a red wiggler or other earthworms…but there are some caveats. (more on this later)

Do worms eat mouldy bread?

Yes, worms do eat mouldy bread. Gross, but true – you can feed worms all kinds of decaying material.

The bread cooking process does alter the form of the individual powdered and liquid ingredients, but even combined in that way, the result can still be eaten and digested by worms.

Pre-cooked bread is perhaps less likely to be offered to composting worms, but food scraps, discarded dried loaves in the form of crumbs, slices or even whole loaves, may find their way into the worm bin.

Moldy bread may actually be that which is best enjoyed by worms. They thrive on dead or decaying food scraps. What’s more, worms do not have taste buds – so do not taste the mold as we might.

Contrary to being repulsed by mold, your average worm will see it as a sign that bread is good to eat. Again, disgusting but 100% true!

Worms can detect the difference between rotten foods and moldy foods. This distinction is crucial to their dietary choices.

So, don’t feel bad about throwing a small amount of plain, moldy bread in with ground eggshells, coffee grounds or otherwise via your worm bin. Just avoid throwing away any spicy foods with it!

Things to be aware of

There are a few things to consider of when feeding your worms bread – molding or otherwise – including:

  • Bread is considered a “brown” food source for worms (meaning it’s a provider of carbon and carbohydrates). Don’t use too much bread and keep your vermicomposting bin 50/50 with brown and “green” food sources (vegetable and fruit scraps which provide nitrogen and other nutrients to your soil)
  • Too much mold in your worm bin or worm farm can cause fungal growth.
  • This is fine in small quantities but keep on top of it because once they get to the fruiting stage, your farm will end up with nasty clouds of mold spores.
  • This is especially bad for anyone with allergies or breathing issues. Clouds of mold are not what you’ll want to be inhaling.
  • The easiest way to deal with it is to break up the mycelium with a small garden hoe or similar tool and mix it with the rest of your bins organic matter. Your worms can eat fungi just fine.
  • Another quick tip if things are getting out of hand is to cover the top layer of mold with manure from chickens, pigs, cows and most commonly, horses.

Do red wigglers eat moldy bread?

Yes, red wigglers do eat moldy bread.

They are commonly used in vermicomposting and are perfectly capable of – and happy to be – eating it!

They are recognised by most as the best vermicomposting worms (if not easiest to start with) and thrive on a mixed diet in the compost bin which includes all types of moldy material.

As your common worm or red wiggler does not have teeth and relies on mold and decay in the transit of food, moldy scraps pass through an earthworms mouth and soft bodies much more easily.

Smaller particles of decayed moldy bread, especially when moist, makes digestion more comfortable.

The membranes of their digest tract are not scratched, damaged or torn by mould and the nutrients, sometimes in the form of gas, are more easily released.

So – along with a great stock of shredded bedding and large, healthy quantities of organic waste, you also can top things off with moldy bread.

What about rotten food?

There is a huge difference between ‘rotten’ and ‘moldy’ food. Rotten food is of no benefit to red wigglers.

Mouldy food contains micro-organisms. Wigglers start feeding mouldy bread and other foods on which mould is developing because it helps to break these micro organisms down.

Red wigglers, as with other worms, breathe through their skin. Rotten food does not contain oxygen and so the worms in your worm bin aren’t going to make the most of these foods

It is therefore advisable to keep an eye on how the composting is developing. Conscientious compost bin owners never deliberately expose their wigglers to the potential peril of rotten food!

Wigglers will welcome moldy food. In fact, you’re actually doing your worm a favor by adding moldy bits and pieces to their feed in the bin.

do worms eat bread blog post image

Rotten waste, however, needs to stay out of any bin you have worms in.

It is easy to distinguish rotten from moldy bread. Rotten bread will be slimy, perhaps having been soaked or affected by other ingredients.

Dry bread seldom becomes rotten unless mixed with other things, such as dairy, or oils and spices.

If in doubt, you can check by tapping the bread! If a powdery discharge is released and it smells mildly gassy, you will know you have moldy crusts.

This is very tempting for red wigglers who will reward you by recycling your moldy food into good quality compost, so do make sure you’ve got mold, not rot, before feeding them the wrong stuff!


Worms will happily eat small quantities of bread.

Feeding it to them is a good way to avoid food waste, but must be supplemented with fruit, a vegetable, etc.

It is far better to give it to your worms than other foods such as citrus, dairy products, meats, etc.

So – start to add a little moldy bread to your worm bin feed occasionally. It’s actually something they can utilize, as well as like to eat.