Earthworms eat dirt and decomposing matter and take in moisture from the soil. They get their nutrition from decaying organic matter in the dirt, such as animal manure and rotting foliage. Worms raised in worm farms eat organic materials, such as decomposing fruits and vegetables, grains, cardboard and teabags.
While worms do eat a variety of foods, there are some foods that are toxic or problematic to worms. Citrus fruits, such as oranges and lemons, contain limonene, which is deadly to worms. Worms in worm farms also should not be fed junk food or meat, which could attract ants and rodents.