Complete Guide To Feeding Apartment Compost Worms

Estimated reading time: 12 minutes

Today I wanted to share my complete guide to feeding an apartment compost worm bin. To get the best, nutrient-rich compost, you need to know what to feed your worms and what to avoid. Many people are surprised to learn that worms love avocado, but a tomato could kill them.

First I’ll share the basics of how worms eat. Then I’ll share some notes about how small space composting is different than outdoor. After, I’ll share a list of foods that are good, bad, and unconfirmed items you can use as worm food. Finally, you will get some basic directions on how to feed your worms and stay consistent.

How Worms Eat

Worms have a gizzard, so you need to add grit. This sounds weird because worms are so soft and squishy and grit sounds dangerous. I understand your concerns- but let’s discuss the basics.

Food enters the worm’s mouth, and moves from their pharynx, and is stored in the crop until it is moved to the gizzard. Similar to a chicken, a worm uses its gizzard, full of stored grit to grind up the food. The gizzard acts almost like the worm’s teeth to help the rest of their digestive track absorb as many nutrients as possible.

If you fail to add gritty items like eggshells, oystershells, or coffee grounds to your bin, your worms will have a much more difficult time digesting food, and producing compost. An added benefit of ground egg and oyster shells is the added calcium and pH balancing impact.

Note About Apartment Vermicomposting

Later in this article, I’ll share what I’ve found to be ‘good’ and ‘bad’ foods you can use to feed your compost worms. I want to note this is specific to my experience, preference, and size of my bin. Some people will argue some foods on the ‘bad’ list are actually quite fine for worms to eat. However, there are a few things I want to note about indoor vermicomposting.

Pests & Fellow Composters

I agree you can add more citrus, garlic, or onions in an outdoor bin. This is often because other types of composters exist in outdoor compost bins. Composters such as black soldier flies, maggots, mites, pseudoscorpions, or small vermin may help with the decomposition process. However, you may not want to attract these insects and rodents into your home.

Black soldier Fly Image
Black Soldier Fly – Powerful Composter

Ph Balance

Another issue that apartment composters must be aware of is the Ph balance of their bin. While worms love coffee grounds, you can kill them if you add too much. Worms prefer a pH around 7.0, but they can live in pH levels of 4.2 to 8.0 or higher.

You must be more mindful of this when you are composting in a small space or apartment. In an outdoor bin, a worm can wiggle away from the problematic food. In a small bin, the worm will try to crawl the sides and likely die if the problem is not eventually remedied.


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Smell

I’ve also made a note of certain foods I’m mindful to limit in each feeding. These are typically Cruciferous veggies, potatoes, asparagus, and similar foods. This is a personal preference thing for sure. However, if you are living in a small home or apartment, be kind to yourself, roommates, and neighbors – skip the stinky stuff.

Good Worm Foods

Below is a list of items that are awesome to feed your compost worms. A note to this list is everything in moderation. Worms love foods like watermelon rinds and sweets. However, a bin full of rinds may attract fruit flies and unwanted pests because of the sugars.

Try to mix a nice variety of foods together to keep your worm bin balanced. The added benefit from this method is a more nutrient food for your worms and better, bio-diverse, vermicompost for your house plants.

Alphabetical List Of Foods You Can Feed Your Worms

composting worms love watermelon
  • Alfalfa Sprouts
  • Apple
  • Apricot
  • Asian Pear
  • Asparagus (in moderation/ smell)
  • Avocado
  • Bamboo Shoots
  • Banana
  • Bean Sprouts
  • Beets
  • Belgian Endive
  • Bell Peppers
  • Blackberries
  • Blueberries
  • Bok Choy
  • Boysenberries
  • Broccoflower (in moderation/ smell)
  • Broccoli (in moderation/ smell)
  • Brussels Sprouts (in moderation/ smell)
  • Cabbage (in moderation/ smell)
  • Cantaloupe
  • Carrots
  • Casaba Melon
  • Cauliflower
  • Celery
  • Cherries
  • Coffee Grounds
  • Collard Greens
  • Corn
  • Cucumber
  • Eggplant
  • Grapefruit
  • Grapes
  • Green Beans
  • Greens
  • Guava
  • Honeydew Melon
  • Horned Melon
  • Iceberg Lettuce
composting worms love avocados
  • Kale
  • Kiwifruit peels
  • Lettuce
  • Lima Beans
  • Mangos
  • Mushrooms
  • Napa Cabbage (in moderation/ smell)
  • Nectarines
  • Papayas
  • Parsnip
  • Peaches
  • Pears
  • Peas
  • Peppers
  • Plantains
  • Plums
  • Pomegranate
  • Pumpkin
  • Raspberries
  • Red Cabbage (in moderation/ smell)
  • Romaine Lettuce
  • Rutabaga
  • Shallots
  • Snow Peas
  • Spinach
  • Sprouts
  • Squash
  • Strawberries
  • String Beans
  • Sweet Potato
  • Turnip
  • Watercress
  • Watermelon
  • Waxed Beans
  • Yams
  • Yellow Squash
  • Zucchini Squash

How To Make Worm Chow

For one reason or another, you may want to have some dry, ready-to-use worm food on hand. Some people use ‘worm chow’ to increase the size of their worms. Other people use it when they don’t have any fruit and vegetable scraps on hand.

Thankfully, it is quite easy to make your own dry worm food without having to make a special trip to the supermarket. Here is a basic recipe you can follow:

  • 2 parts oats
  • 1 part cornmeal
  • 1/8 part crushed eggshells
cleaned and dried chicken egg shells for worm food grit

To make:

  1. Bake your eggshells at 20 for 10 minutes to kill any potential salmonella bacteria
  2. Add baked eggshells to the blender and process on high for 45 seconds.
  3. Add cornmeal and oats to the blender.
  4. Blend on high for 45 additional seconds
  5. Store in an air-tight container.

To Use:

How much you use depends on how many worms you have in your bin. Start first by sprinkling 1 tablespoon over the top of a small section of your bin.

Mist the dry food with a spray bottle and cover it with moist bedding.

I’ve seen different recipes for dry worm food on different blogs and youtube videos over the years. Corn meal is a common ingredient, in all recipes. You could also substitute the crushed egshells for ground owyster shells.

The oats and corn meal provide an easy to digest meal and the eggshells grit, calcium, and act as a Ph balancer. I always recommend using the least processed items when using your worm chow.

And for the best vermicompost/ fertilizer, use real fruit and vegetable scraps whenever possible for greater biodiversity.

Bad Worm Foods

Now let’s talk about which foods you should not feed your composting worms. If you’ve accidentally added a very small amount of any of these items it will probably be fine. For example, a garlic peel will not doom your worms to death.

However, a bin full of onion and orange peels will definitely kill your worms.

I also added pet waste to the list as it is a common question from beginner vermicomposters. It is true that in nature, composting worms live in piles of manure. But, it is not advised to add pet waste to your bin because of bacteria, pH balance, and smell.

Alphabetical list of foods you can feed your worms

picture of lemons, limes, oranges not to feed apartment compost bin
  • Processed food
  • Animal & pet waste
  • Garlic
  • Green Onions
  • Leeks
  • Lemons
  • Limes
  • Mandarins
garlic onion bad worm food
  • Mandarin Oranges
  • Meat
  • Onion
  • Oranges
  • Pineapple
  • Potatoes
  • Tangelo
  • Tangerines
  • Tomatillo
  • Tomato

Unconfirmed Worm Foods

I’ve listed some types of fruit and vegetable I’ve never tried in my own bin. If you’ve tried any of these foods, please leave a comment below. I would love to keep the list up-to-date with a diverse amount of foods we can feed our worms.

  • Artichoke
  • Atemoya
  • Beans
  • Cactus Pear
  • Chayote
  • Cherimoya
  • Coconuts
  • Cranberries
  • Dates
  • Endive
  • Escarole
  • Feijoa
  • Gooseberries
  • Fennel
  • Figs
  • Hominy
  • Jerusalem Artichoke
  • Jicama
  • Kohlrabi
  • Kumquat
  • Longan
  • Loquat
  • Lychee
  • Malanga
  • Mulberries
  • Okra
  • Passion Fruit
  • Persimmons
  • Prickly Pear
  • Pummelo
  • Quince
  • Radicchio
  • Radishes
  • Rhubarb
  • Ugli Fruit
  • Water Chestnuts
  • Yuca/Cassava

How To Feed Your Worms

Now that you know what foods are good and bad for your worms, it’s time to actually feed your worms.

How I prep my compost worm food:

Time needed: 30 minutes.

These are the basic steps I take to prep my worm food. I will often save food scraps untill I can fill a blender- saving :

  1. Bake your eggshells

    Bake at 350 for 10 minutes to kill any potential salmonella bacteria

  2. Add cooled eggshells to the blender

    Process eggshells in blender on high for 45 seconds. Avoid any shell dust and let the shell dust settle before opening the blender. I like to crack the blender a little water, and turn on the blender again. This helps reduce the amount of shell dust that can escape.

  3. Add food scraps to the blender

    Add your food scraps to the eggshells in the blender along with a quarter cup of filtered water. Avoid adding tap water as it often chlorinated. Start blender on low and slowly increase speed.
    Add a little water at a time until everything blends into a slurry.

After I mix all of the food I can feed it directly to my worms or store it for future use.

Pocket Feeding Method Explained

I use a pocket feeding method to feed my worms. That means, I open the bin and chose a corner – think of the five-side. of a dice. I will dig a small hole, being careful not to hurt the worms in the area.

Pocket each corner and one in the middle like a five on a dice.

Next, I place a few scraps of newspaper at the bottom of the hole. This paper absorbs the added liquid, and any liquid from decomposition. I then place 1/4 cup of the slurry into the hole, on top of the newspaper. I then add some addition dry newspaper scraps on top for extra absorption. Finally, I use the material I moved when digging the ole to cover the feeding area.

Often I’m left with a blender full of worm food slurry that I need to store for the future. The easiest way to consistently feed my worms the same amount on the same schedule is to freeze a pre-measured amount.

I’ve found the best way to get rid of paper waste and pre-measure my worm food is with toilet paper rolls. You could also use cardboard egg crates, fill them like an ice cube tray, and freeze. Once frozen you can rip off an egg section and follow the same pocket feeding method.

Summary

I hope you feel confident in feeding your compost worms from now on. Feel free to refer back to this guide whenever you have a question. Share any tips that you found helpful, let me know what you though of today’s article.

Be sure to share any foods your worms loved or hated that I don’t have on the list. If you’ve tried any of the unconfirmed items in your bin, be sure to share your experiences. I will keep this list up to date to help any future baby vermicomposters!