Can Compost Worms Eat Bread?

There are so many food scrapes to add to a worm bin to keep our wriggly composters happy and healthy. Fruit, vegetable peels, and other food scraps can all be tossed to the worms, where they will turn them into beautiful worm castings. It really doesn’t matter whether it is rotten food, moldy food, or even starchy food; a worm farm can break it down.

But when it comes to bread, you want to take a more careful approach. Grains have a tendency to attract pest animals to your worm and composting bins more than other food scraps. If you will be giving food waste like stale bread to your worms in their worm bins, you will want to make sure you have the right worms and environment for them to break it down fast. Read on to learn how! 

Do Worms Eat Stale, Moldy Bread?

Worms will consume any organic matter, including moldy bread and other moldy materials. Spicy foods are generally avoided by worms, but vegetable scraps and moldy composting material is fine for worms because it is the bacteria from the composting process that feed the worms. Certain mold growth, like black mold or dangerous species, should not be added to composts or worm bins and should be sealed in a bag and disposed of safely. 

Stale bread is also a perfectly acceptable food for worms and can regularly make up a small part of their diet. While moldy bread tends to be extra moist, stale bread lacks moisture and may be harder for worms to absorb unless additional moisture is added or wet organic waste is added to it. Stale bread can be broken into small pieces, whereas fresh or moldy bread can be tossed in as is since it will be consumed into compost much faster. 

Common Compost Worms

While most worms will be able to break food items into worm castings and aid in the composting process, the two most common types are nightcrawlers and red wrigglers. Occasionally the term earthworm will be used, and in most cases, we can just assume that is a naturally occurring soil worm for that area. Nightcrawlers can usually be found on your own lawn or at a local bait shop, whereas red wriggles can be found online or at specialty garden shops. 

Red WrigglerExtremely Fast ComposterDry Environments
Night CrawlerFound in any SoilBreaks food down slower than other composting worms

Red Wriggler

These worms make the highest quality compost in the shortest amount of time. These worms will break down animal manure, coffee grounds, uneaten food, cooked foods, and any waste from a food garden. A rule of thumb is that red wriggle worms can consume about their body weight in organic waste and food sources every day as long as it is a balanced diet and the soil is moist enough.  

Food with preservatives will take longer to break down than fresh foods, but even so, with enough other uneaten food scraps, red wrigglers can get through even some of the most processed wastes. Dairy foods and meat scraps, as well as oily foods, can be added in very small doses as long as plenty of animal manure or other compost worm favorites are added too.


As long as you give your soil a food supply, you’ll attract nightcrawlers. If you have a compost bin and want to speed up the composting process, or if you want to build a worm bin where you can feed anything from grain food to fruit scraps to worms in exchange for castings, you’re going to need to get the worms first. If you plan on using nightcrawlers, you won’t have to go far. 

Nightcrawlers are a common earthworm that could be under your feet this very second. This means all you need to do is dig them up and add them to your bin. If you want to increase your success, you should water near plants and other fertile soil areas in the evening and then dig for night crawlers before the sun comes up the next morning. The water will draw the worms up, and nighttime is when they are most active and easiest to dig up. 

How to Feed Worms Bread?

Feeding bread to worms is much more efficient if you take a few steps to prepare it for the bin. Moldy bread and stale bread can be added, but different preparations should be taken to avoid spreading mold spores around the kitchen. Putting moldy bread in a food processor, for example, may not be the best idea, but stale bread could be pulverized to make it as easy as possible for your composters to devour. Check out these steps to help your worms eat bread better.

Cut into Small Pieces

Large quantities of bread can be added to worm bins if they are cut into small pieces or run through a food chopper first. Adding a layer of small pieces of bread followed by a food layer can help the worms find the bread faster. Moldy bread can be thrown in directly because it is already partially decomposed, but stale bread should be made as small as possible and crumbed into tiny bread pieces if possible. 

Keep at Less than 10% of Total Feed

The amounts of bread mixture in the worm bin are determined by the total mass of worms in your system and the additional food scrap contributions you will be adding. Rotten bread can be added in a little bit higher quantities than fresh slices of bread, and stale bread should be reduced in quantity even further. Bread with soil will break down faster than bread with acidic foods or spicy foods. 

Mix Well 

The closer to the surface you place food scraps, the less likely large numbers of worms will come to the top and eat them. Worms prefer the seclusion of the lower levels of the worm bin and like food that is brought to them. Mixing bread crusts and pieces of bread with soil, compost, and other organic wastes will increase the speed by which worms will turn them into castings. 

Cover With Compost

Worm blankets and layers of compost can be used to encourage worms to come closer to the surface to eat newly added dry bread. If a dense, moist layer of the cover is placed above the newly added sources of food, then worms will quickly devour it and move in great numbers to these spots. Worm blankets also have the added benefit of keeping rodents and other grain-loving wild pests out of your worm bin.

Can Too Much Bread Harm Worms in Compost?

While too much bread will not necessarily harm worms in compost, it can start causing problems for the overall soil environment. Bread can lead to a build-up of mold and bacteria that can slow decomposition and create unpleasant odors.

A moldy patch growing on the top of a worm bin can lead to airborne mold and other issues when you open the bin or if it is hit by a breeze. Large areas of slowly rotting bread will be avoided by beneficial microbes especially if anaerobic conditions have formed. 

To avoid these issues, make sure that the amount of bread mixed into the worm bins does not exceed 10% of the total waste. Grind or cut all bread into small pieces and mix it with the other food scraps. Never drop a whole loaf of bread in one spot, as it will take a long time to break down and will increase the chances of attracting pests. Worm feeding with bread can be successful as long as the worm’s needs are considered first.