What do worms eat in the wild?
Worms are very different from that finicky cat next door that only eats specific types of gourmet cat food. They'd probably eat the cat food too, but they'll happily chow down on cardboard, sawdust, leaves, fruit rinds, and whatever else they have access to. In the wild, this amounts to whatever is physically around them. Surface worms and deep-earthworms sustain on slightly different diets, but the core ingredients are consistent: bacteria, fungi and algae. As mentioned above, surface worms will eat almost anything that contains these ingredients; if it's rotting, decaying, or just vaguely organic they'll likely want to take a bite. The deeper-dwelling worms have it even easier than their surface siblings; earthworms mostly eat dirt that contains the necessary bacteria for their nutritional needs. Their ability to breathe through their skin makes it easy for them to spend nearly all their time underground just eating, eating, and eating. Occasionally, they'll return to the surface to breed and then it's right back to eating. Wild worms are basically tiny food processors that take food in through one end and expel fertilizer, or "worm casts" out the other.
Having worms in your garden is generally beneficial because of their constant burrowing and fertilizing that aerates the dirt and breaks up hard-to-penetrate soils without any additional work on your part. It's possible to lure wild worms to your garden by spreading mulch in the spring or by leaving any of the food choices mentioned above. A more concentrated way of doing this is of course, composting.
What can I feed my pet worms?
Because of these broad eating preferences worms have become a popular addition to the world of composting. Rather than just throwing stuff in a bin and waiting, it's nice to know that there are a bunch of tiny, slimy machines helping the process along. So when you get your first batch of pet worms and find yourself asking What do worms eat? then worry not; they're likely the lowest maintenance house guests you'll ever have. Next time you're making a fruit salad set the rinds aside. Start hanging on to vegetable matter instead of dropping it in the trash. In fact, feel free to hang onto your used coffee grounds and tea bags for their next meal. Anything you can eat is probably on their menu so holding on to your table scraps is a great first step. There are only a few things you may want to steer clear of or feed in moderation: avoid putting in meat or dairy products as it could stink up your house and attract flies more than benefiting your worms. Moderating onions, garlic, and citrus may also be wise for similar reasons. In terms of keeping your worms healthy, it's easy to apply similar human dietary suggestions; too much oil, grease, or salt isn't good for anyone. If you're interested in speeding along the feeding process than cutting up your leftovers will make it easier for your worms to process it quickly. Even if you don't bother, they can still process the food but it can just take longer. Another rule of thumb is that you should make sure that you're varying their diet. Feeding them junk mail or cardboard is fine as long as you alternate it with eggshells or plant matter. Keep it varied and try to regularly incorporate organic materials.
Worms eat fungi, algae, and bacteria found in healthy soil.
What do baby worms eat?
Since worms are hermaphroditic you don't have to worry about collecting male and female worms for your composting. As long as you have two then reproduction is possible! Once an egg case has appeared it may be up to three weeks until new worms emerge. The numbers vary but usually an egg case will produce anywhere from 2 to 7 new baby worms. During the stage within the cocoon you don't have to worry about feeding them anything as they are gaining nutrients from the case itself. Following their hatching, they still might not eat much for several months while they mature but their diets will be similar to their parents', just smaller. Baby worms look like small pieces of white string and won't get their pink color and the signature "band" around their middle until they mature. If there are lots of baby worms appearing in your crate then good news! Just like with other animals, frequent reproduction among worms indicates a habitable and even hospitable environment. Once new worms are mature then continue feeding them the diet indicated above, but be aware: more worms does mean more food might be required. Just keep an eye on your worms and make sure the food isn't disappearing too quickly.