Feeding Your Worms

worm composting bin

How to Feed Your Worms
Select foods that are suitable for worms including most fruits, vegetables, cereals and grains, and other organic items like cardboard and tea bags. It is best to cut food scraps into small pieces before placing them in the bin. The smaller the pieces the more surface area there is for bacteria to start breaking down the food, making it easier for the worms to consume. Some people put their food scraps, including eggshells, into a blender and make a slurry. The worms seem to love this, but it is not necessary.

Keep shredded black and white newspaper over the food at all times. Newspaper or bedding helps keep the bin dark and moist and discourages fruit flies. Other organic material such as burlap or shredded cardboard or paperboard can also be used. The worms live in these materials and they also eat them.

To feed the worms, place the food under the newspaper in a different part of the bin each time. Do not bury the food in the castings.

How Much Food?
Worms need to adjust to their new home and new foods so do not overfeed them the first few weeks. In addition to the food you are giving them, they're eating their new bedding. Once they are settled, comfortable and happy they will quickly munch through their food. The bin will require more food as its population grows.

You want to feed the worms just ahead of their rate of consumption. Before adding new food, consider:

  • Have they had enough time to consume old food?
  • Is there food remaining because they do not like it?
  • Has the food not been broken down enough by bacteria for the worms to consume it?

If there is a little food left and the worms are eating, additional food can be added. But if food is left due to one of the other reasons, cover it with newspaper and don't feed again for a week or remove the food from the bin.

worm banquet

Feeding Schedule
feeding timeUnlike other critters, worms don't demand to be fed on a schedule. They can be fed once a day, every two or three days, or once a week. You can go on vacation for a month without worrying about them. Just give them a regular amount of food before you leave and place plenty of shredded newspaper, cardboard or paperboard on top of the food. Make sure you leave the bin in an area where the temperature will not get too hot (not over 90º) and the cover material is wet enough that it will not dry out.

Happy redworms will eat half their weight in food every day. That doesn't sound like a very large quantity of food because they're so small, but when you get a few thousand worms living in a bin, food disappears rather quickly.

Other Additions
Because worms have no teeth, they need to take in grit with their food. Rock dust or crushed oyster shells offer grit for their diet and can also help correct problems if you've added too much food to the bin. These can be purchased at most garden stores. To add these powders to the bin, sprinkle a small amount on the food scraps once or twice a month.

Pulverized eggshells are an excellent source of grit. If you are adding eggshells to your bin you probably won't need to purchase other types of grit.

Trouble Shooting

Problem: Moldy food
Solution: If you have fed the worms too much, the food might become moldy. Remove moldy food as worms are unlikely to eat it and it makes the system vulnerable to infestations from other microorganisms.

Problem: Offensive odor
Solution: Uneaten food has become anaerobic. Make sure there is a generous amount of damp newspaper or cardboard placed over the food and stop feeding for a week. Add rock dust or crushed oyster shells.

Problem: Worms trying to escape
Solution: Bin may be too wet or too dry. Add more dry bedding if too wet, or moisten bedding if too dry.

Examples of Worm Food

worms eat fruit

Fruit: apples, pears, banana peels, strawberries, peaches and all melons

Vegetables: beans, cabbage, celery, carrots, cucumbers, tomatoes, all greens, corn, corncobs and squash

Cereals and grains: oatmeal, pasta, rice, non–sugared breakfast cereals, corn meal, pancakes

worms eat eaggshells and tea bags

Miscellaneous: coffee filter paper, tea bags, eggshells, dead flowers

Other food/bedding: newspaper (no shiny or coated paper), cardboard, paperboard, paper egg cartons, brown leaves

Use Caution When Adding These

Breads — can attract red mites
Potato skins, onions, garlic, ginger — get consumed slowly and can cause odors
Coffee grounds — too many will make the bin acidic

Do Not Feed

Meat, poultry, fish, dairy — protein attracts rodents
Potato chips, candy, oils — worms do not like junk food and these attract ants
Oranges, lemons, limes — citrus has a chemical substance (limonene) that is toxic to worms

Definite No–No's in a Worm Bin

Non–biodegradable materials that do not belong in your bin include plastic, rubber bands, sponges, aluminum foil, glass, and dog or cat feces.