Worms Eat My Garbage, 35th Anniversary Edition

How to Set Up and Maintain a Worm Composting System: Compost Food Waste, Produce Fertilizer for Houseplants and Garden, and Educate Your Kids and Family


By Mary Appelhof

By Joanne Olszewski

Foreword by Amy Stewart

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For more than three decades, this best-selling guide to the practice of vermicomposting has taught people how to use worms to recycle food waste into nutrient-rich fertilizer for houseplants or gardens. Small-scale, self-contained worm bins can be kept indoors, in a basement, or even under the kitchen sink in an apartment — making vermicomposting a great option for city dwellers and anyone who doesn’t want or can’t have an outdoor compost pile. The fully revised 35th anniversary edition features the original’s same friendly tone, with up-to-date information on the entire process, from building or purchasing a bin (readily available at garden supply stores) to maintaining the worms and harvesting the finished compost.



Title Page




The Worm Composter Checklist

1. It Starts with a Worm

2. Getting Started

3. Choosing the Right Worm Bin

4. Choosing the Right Bedding Material

5. Using the Right Kind of Worms

6. Acquiring Your Worms

7. Setting Up Your Worm Bin

8. What Can Your Worms Eat?

9. Taking Care of Your Worms

10. Frequently Asked Questions

11. Other Critters and Pests

12. How to Use Your Vermicompost

13. Treating Waste as a Resource

Appendix A: Record Sheet

Appendix B: Annotated References

Metric Conversions

Appendix C: How Many Worms in an Acre or a Hectare?






Cultivate Your Green Thumb with More Books from Storey


Share Your Experience!


In 2001, I called Mary Appelhof and told her that I wanted to write a natural history of earthworms. "At first I wasn't sure anyone would want to read a book about worms," I said, "but I'm finding out that everybody has an earthworm story."

"Oh, they do!" she said, and proceeded to tell me hers. She built her first worm bin in 1972, and published a brochure about worm composting a year later. "I sold it to anyone who would send a quarter and a self-addressed, stamped envelope," she said.

"Did it sell?" I asked.

"It was a hit!" she said. "I did a survey back then on people's attitudes towards using worms for home garbage disposal. Only 25% of the people who responded to the survey said they couldn't stand the idea. I figured that meant 75% were willing to consider it."

That was Mary: the eternal optimist, the tireless evangelist. Anytime she saw an opportunity to promote earthworms, she took it. She taught classes at any school or nursery that would have her, she spoke at conferences, produced educational videos, and began answering to the name "Worm Woman."

She published Worms Eat My Garbage in 1982, when self-publishing a book meant stacking thousands of copies in the garage and peddling them out of the trunk of the car. It was the only book about worm composting on the market at the time, and remains the best: it's thorough, well-researched, and entertaining. To everyone's astonishment but Mary's, the book sold 100,000 copies — but not overnight.

"It only took me twenty years!" she said. "When I started, I envisioned huge piles of garbage and huge quantities of worms. I didn't have the wherewithal to make that happen, but I did know how to get worm composting going one household at a time. So that's what I did."

The book you hold in your hands is nothing less than Mary Appelhof's prescription for saving the world — in your own backyard. It's now been twenty years since I started my first worm bin. In that time they've proven to be surprisingly good pets: clean, industrious, self-­sufficient, and always up for the job of devouring compost and enriching the soil.

If you're embarking on your first adventure with earthworms, I congratulate you on your decision and promise that before long, you're going to have your own earthworm story to tell.

Amy Stewart, author of The Earth Moved: On the Remarkable Achievements of Earthworms


I met Mary Appelhof in 1982. Her first gift to me was a 1-2-3 Worm Box, complete with worms. At work, I used the paper shredder to shred newspaper. Adding the paper and vegetable scraps to the bin, I then placed it under a bench in my greenhouse and totally forgot about it. About a month later, Mary came to visit and checked up on the worms. Imagine my surprise when she pulled back the bedding to find one of the most prolific masses of worms she had ever seen. I have been worm composting since that time, and I occasionally forget about these amazing creatures, yet they continue to perform. Today, I have two bins. The large outdoor one I made from cedar pickets, and the second, small indoor bin is Mary's Worm-A-Way that I use for demonstrations.

Mary passed away in 2005 and the first two editions of Worms Eat My Garbage were written in her own words. Many times she used the first person "I" to explain her ideas and reasoning. I have chosen to leave her words intact. In the new sections of the book, I also used the first person to express myself. Although it could be confusing to have two authors each use "I" in one book, rest assured that I agreed with Mary on her ideas and I believe she would agree with mine.

This third edition continues to answer the most common vermicomposting questions while updating and expanding on the scientific data. Mary had a gift for taking difficult information and presenting it in a simple fashion. As a former middle school science teacher, I have attempted to continue that practice. This update also answers questions Mary asked in her previous editions. Much has happened in composting, vermicomposting, and recycling in the last two decades. It was Mary in 1993 who coined the term "worm workers." This revision brings us up-to-date on what worm workers are doing and hopefully inspires you to become a worm worker as well. After all, if worms eat my garbage, they will eat yours, too.

— Joanne Olszewski, Worm Woman 2.0


The Worm Composter Checklist

  1. 1. Read Worms Eat My Garbage.
  2. 2. Weigh organic kitchen waste for two to three weeks to get the average amount produced in your household so that you can determine the right size bin for the amount of waste you produce.
  3. 3. Determine the quantity of worms you need and order worms.
  4. 4. Purchase a bin or select the size of container required and assemble the materials.
  5. 5. Determine what types of bedding are available, and either order materials or scrounge.
  6. 6. Build or assemble your bin.
  7. 7. Prepare the bedding. If using manure, prepare it at least two days before the arrival of your worms.
  8. 8. Add worms to the bedding.
  9. 9. Bury your food waste in the bedding.
  10. 10. Check moisture levels periodically; look for cocoons and young worms.
  11. 11. Harvest worms and prepare new bedding.
  12. 12. Use the vermicompost or worm castings on houseplants or in your garden.

It Starts with a Worm

Earthworms in nature play an important role in recycling organic nutrients from dead tissues back into living organisms. They do this without fanfare; rarely does anyone see them perform their tasks.

If you decide to use composting worms to process your own organic kitchen waste, you will see them at work. You will see mounds of disagreeable material converted noiselessly, with almost no odor, to material you can use directly on your houseplants and in your garden. You will enjoy healthier-looking plants, better-tasting vegetables, and money in the bank. You will spend less on fertilizers and trash disposal. Some of you will be serving fish for dinner — caught using "your" worms as bait. Hopefully, you'll also gain a better appreciation of the intricate balance and interdependencies in nature. You will be treading more gently upon the Earth.

As your gardens are enriched, so is your life and mine. You will have joined the worm-working adventurers who say, "Worms eat my garbage." Isn't that a grand beginning to a task that needs to start somewhere? You, personally, can make it happen.

What to Call Your Setup

Some people use the term "home vermicomposting system" because it sounds more sophisticated than "worm bin." They are right on both counts; it is sophisticated, and it is a system. The system consists of five interdependent parts:

  • Physical structure: A box or container
  • Biological organisms: The worms and their associates
  • Controlled environment: Temperature, moisture, acidity, ventilation
  • Maintenance procedures: Preparing bedding, burying kitchen and food waste, separating worms from their castings
  • Production procedures: Making use of the castings (worm manure)

I hesitate to use "home vermicomposting system" exclusively because the term itself might frighten away those who feel more comfortable with "worm bin." It sounds less intimidating to suggest taking a plastic container or wooden box and putting holes in it to provide a source of air. Then add damp bedding and worms, bury food waste, harvest worms, and set up fresh bedding as necessary. If calling this system a worm bin encourages you to try the technique, no other term is better.

On the other hand, the system truly is complex. Much more can be learned about it: Just what is going on in that bin? Are the worms really eating the food waste, or are they eating the microbes, bacteria, protozoa, molds, and fungi that are breaking down the food waste? Can conditions become too acidic? How can you tell? What kinds of food might cause overacidity? When is the best time to harvest if you want the greatest number of worms for the least amount of time and effort? When do you harvest to get the best castings? What is the best size of container to bury a given quantity of food waste?

If you like to compare notes, for example, about ideal temperature for worm cocoon production or about acceptable levels of anaerobiosis (absence of oxygen), you might want to say you have a home vermicomposting system. I have such a system. I know a great deal about vermicomposting, but I have a lot more to learn. For myself, I just say, "Worms eat my garbage. Wanna see my worm bin?"

Getting Started

When deciding what kind of worm bin to get and where to put it, consider both the worms' needs and your own.

That may sound elementary, but I've learned from experience that there are a few basics you should think about in advance. Adjusting your thinking early will help determine later how successful and enjoyable a worm bin is for you.

To meet your needs, a home vermicomposting system will have to measure up to your expectations, provide a convenient method for converting organic waste to a usable end product, and satisfy your idea of suitable aesthetics. Potential end products are a supply of worms for fishing, worm castings for plants, or vermicompost for use in your garden. If you do use worms for fishing, it is important that you are aware of their proper disposal. (See chapter 5 for more information on worms as an invasive species.)

What to Expect

The effectiveness of your vermicomposting system will depend partly upon your expectations and partly upon your behavior. You can reasonably expect to bury a large portion of your bio­degradable kitchen or food waste in a properly prepared worm bin, check it occasionally, make judgments about what must be done, then harvest worms and vermicompost or worm castings after a period of several months. You cannot expect to merely dump all the trash from your kitchen into a worm bin, add some worms, and come back in only two weeks to collect quantities of fine, dark worm castings to sprinkle on your houseplants. Either revise this unreasonable expectation to something more realistic, perhaps using the ideas below, or don't even set up a system.

Compost or Castings?

Vermicompost is a more general term than worm castings. A casting is manure, the material deposited from the anus after it has moved through the digestive tract of a worm. Vermicompost contains worm castings but also consists of partially decomposed bedding and organic waste with recognizable fragments of plants, food, and bedding. Worms of all ages, cocoons, and associated organisms may be found in vermicompost. If a worm bin is left untended for six months or so, worms will eat all of the bedding and organic waste, depositing castings as they do so. In time, they will have reingested the materials a number of times. Then the entire contents will have been fully converted to vermicast, which is completely worm-worked and reworked material with a fine, smooth texture. Vermicast is considered overworked and has probably lost nutrients. At that stage, since no food remains for the worms, most worms will die and be decomposed by the other organisms in the worm bin. The few worms that live will be small, inactive, and undernourished.

Your Goals

The difference between reasonable and unreasonable expectations has to do with the kind of food waste you bury, the environment you provide for the worms, the length of time you are willing to wait to observe changes, and the character of the end products. Success isn't that difficult when you know what you want. Guidelines to help you make reasonable judgments about maintaining your worm bin effectively depend on your goals.

Goal: extra worms for fishing

Maintenance level: high

Some of you will want to produce more worms than you started with so that you have a ready supply for fishing. Expect to harvest your bin every two to three months, transfer worms to fresh bedding, and accept vermicompost that is less finished than if you were to leave the worms in their original bedding longer.

Producing more worms for fishing bait means having less finished vermicompost.

Goal: finished worm castings for plants

Maintenance level: low

Those who prefer to obtain castings in the most finished form have the advantage of extremely low maintenance. You will bury food waste in your worm bin over a four-month period, then leave it alone. You won't have to feed or water the worms for the next few months, letting the entire culture proceed at its own pace. The worms will produce castings continuously as they eat the bedding and food waste. The disadvantage of this program is that as the proportion of castings increases, wastes that are toxic to the worms accumulate, and the environment for worms becomes less healthy. They get smaller and stop reproducing, and many die. As you wait for the worms to convert all the bedding and food waste to castings, you will have to deposit fresh batches of food waste elsewhere — perhaps in a compost pile or in a second worm bin.

In time, your worm bin will provide a quantity of fine castings to give you a homogeneous, nutrient-rich potting soil. If you choose this goal, you can alternate from one bin to another. Or you may have to purchase worms every fall when you set up your worm bin. This low-maintenance program enables you to vermicompost inside during the cold winter months, compost outside in the traditional manner when the weather warms, and have finished worm castings from your indoor worm bin sometime during summer.

A nickname for this maintenance approach might be "the lazy person's technique." However, if you use two bins, it's actually a pretty efficient system; "the smart person's technique" fits the situation better.

Worm castings enrich the soil for your garden or ordinary houseplants.

Goal: continuous worm supply plus vermicompost

Maintenance level: medium

Middle-of-the-roaders can opt for a program that requires just enough maintenance to keep the worms healthy. You will harvest fewer worm castings, but you should still have ample quantities of vermicompost to use on your houseplants and ­garden and enough worms to set up your bin again. About every four months, you will prepare fresh bedding and select one of several techniques for separating worms from vermicompost. These techniques are described in chapter 9.

It should be apparent that the effectiveness of your home vermicomposting system depends as much upon you as it depends upon the worms.

Location, Location, Location

The convenience of your home vermicomposting system is directly related to its location. There are various possibilities. For some of you, locating your worm bin will depend considerably on what it looks like. A homemade bin may be practical but not necessarily beautiful. If it is a custom-made unit of laminated maple with sturdy legs on ball rollers and looks like a piece out of a Nieman Marcus catalog, you will want it where you can show it off most readily. Constructing your own worm bin is, of course, always an option; DIY instructions abound online, and classes may be offered at some organizations (see Resources for more details).

More realistically, before you decide where to locate your worm bin, (1) determine how large your unit must be to process your kitchen waste (see chapter 1 for more on this), (2) assess the space you have available, and (3) determine whether you want it to be merely functional and out of the way or the center of attention. To state this another way: How many guests do you want tramping through your basement? Or how many guests can deal with sitting on a window-seat worm bin in the dining room? From my experiences, I can guarantee you, until worm bins are common, almost everyone who visits is going to want to see yours!

The Kitchen

Since food preparation is done in the kitchen, the most convenient location for a worm bin might be there, too. One of my friends has a worm bin on top of his dishwasher with a cutting board serving as a lid. When he is through chopping cabbage, celery, or whatever, he just slides the top back and scrapes the waste into his worm bin. You can't beat that for convenience!

The Patio

An outdoor patio off the kitchen is an excellent location for a home vermicomposting unit if it will be out of direct sun during the summer months. It is close to the origin of food waste, is near a water supply for maintaining proper moisture, and has plenty of ventilation. Just as you can expect to get dirt on the floor when you mix potting soils to repot plants, know that the periodic maintenance of separating worms from vermicompost can get messy. Doing it on the patio will keep the dirt outside. In climates where freezing temperatures are a problem, insulation and supplemental heat can keep the worms going. I describe some of these adaptations in chapter 9.

The Balcony

Apartment dwellers often have limited space. In warmer climates, many people living in apartments find that their balcony accommodates a worm bin and a few container plants. They like the appearance of the plants and feel good about doing something useful with their food waste. The plants give them a place to put the vermicompost produced in the worm bin.

The Garage

A well-ventilated garage would be a satisfactory location for a worm bin if it blocks freezing temperatures in your production area. It also will provide shade during hot weather.


Locating a worm bin in a basement, if you have one, has the advantage of keeping it out of the way. If problems develop — there might be short-term odors or occasional fruit flies — the worm bin is not in the immediate living quarters. You might find it inconvenient to always go downstairs whenever you want to bury food waste, however. Basements do meet the worms' temperature needs, being cooler in summer and rarely freezing in winter. Since they are out of sight and not in the way for most people, many worm bins, including mine, are located in a basement.

Your Worms' Needs

To make the worms happy, you'll need to think about temperature, moisture, acidity, and ventilation. Equally as important, to make yourself happy, you'll want to consider your expectations, sense of convenience, and aesthetic preferences.

Keeping Them Warm

You should be using the redworm, Eisenia fetida; the red tiger, E. andrei; or a combination of both. These are best for home composting, for reasons that I will discuss later (see Redworm). They feed most rapidly and convert waste best at temperatures between 59 and 77°F (15 and 25°C), with an optimal temperature of 77°F. They can work their way through food waste in a basement bin with temperatures as low as 50°F (10°C), but below this they reduce their feeding. Ultimately, these worms can survive in temperatures between 32 and 95°F (0 and 35°C). Below 39°F (3.9°C), cocoon production and development of young ceases.

Redworms have successfully weathered cold northern winters in pits dug into the ground that were covered with manure, straw, and leaves to provide heat, food, and insulation. The problem with an outdoor pit for winter food waste disposal is disturbing the protective snow covering to bury food waste. When the temperature drops to zero, such protection saves the worms, but your food waste also piles up!

Temperatures over 86°F (30°C) promote microbial activities that can consume oxygen that the worms need. The temperature in moist bedding is generally lower than the surrounding air because evaporation of moisture from the bedding in a well-­ventilated place has a cooling effect. Locations that could get too hot include a poorly ventilated, overheated attic; outside under a hot sun; and in a greenhouse in higher elevations.

Keeping Them Happy

Maintaining moisture. All worms need moisture. They "breathe" through their skin, which must be moist for the exchange of air and the excretion of waste to take place. You can add water to dry bedding when necessary. Too much moisture, present as water standing in the bin, can reduce available oxygen and cause worms to "drown." This can be a problem in plastic bins, a point I will discuss in more detail in chapter 9. Location is another factor with excess moisture. Place your worm bin where there is no danger of natural flooding, which could also drown the worms.

Maintaining acidity. Redworms can tolerate a fairly wide range of acidity in their environment, but slightly acid conditions are best. The 14-point scale for determining degree of acidity is called pH. The most acid reading would be pH 1; the most alkaline reading would be pH 14. Neutral is pH 7, meaning that the medium is neither acid nor alkaline. A wide range from pH 5 to pH 9 is suitable for redworms. In a worm bin with a pH of 4, you may find worms dying or trying to escape from the excessive acidity in their environment. Providing too much acidic food would be rather like pouring a bottle of vinegar into a worm bin — not a good idea! The most accurate method for testing the pH of your worm bin is to use a pH meter. Simply place the meter in at least three different places in the bin to check the pH level. If you don't have a meter, then use the smell test. If it smells bad, it might be a pH problem. I personally like using the meter because it is a simple, accurate, economical way to determine the pH.

Maintaining Ventilation. Worms use oxygen in their bodily processes, producing carbon dioxide, just as we do. It is important that you allow air to circulate around your container as a structural unit. Wrapping it in a plastic bag, for example, might be tidy, but the worms would quickly smother. For more on ventilation, see chapter 3.

Choosing the Right Worm Bin

A variety of containers make satisfac­tory worm bins. These range from commercially available vermicomposting units to containers you adapt or bins you build yourself.

Regardless of your choice, aeration is an essential function of the container's controlled environment. The greatest concern people express when they hear about placing kitchen waste in a container to be kept inside the home is "But won't it smell?" The answer: "Not too badly if it is properly set up and maintained." That is, when your bin is set up so that it has good airflow.

Ensuring Good Airflow

We are trying to create an aerobic


  • “Mary Appelhof's prescription for saving the world — in your own backyard. ... [My own worms] have proven to be surprisingly good pets: clean, industrious, self-sufficient, and always up for the job of devouring compost and enriching the soil.” — Amy Stewart, author of The Drunken Botanist

    “Mary Appelhof turned complicated science into understandable and usable advice. She’s sculpted into my Mount Rushmore of the founders of the organic movement.” — Jeff Lowenfels, author of Teaming with Microbes: The Organic Gardener's Guide to the Soil Food Web

On Sale
Dec 26, 2017
Page Count
192 pages

Mary Appelhof

Mary Appelhof

About the Author

Worms Eat My Garbage was originally written by Mary Appelhof (1936–2005), an international authority and lecturer on small-scale vermicomposting whose honors included a National Science Foundation grant and the National Recycling Coalition’s Recycler of the Year. Joanne Olszewski, a close friend of Appelhof’s, has updated the book for the 35th Anniversary Edition. Olszewski is a fellow vermi-enthusiast and the owner of Wormwoman Inc., which manufactures and sells the Worm-A-Way worm bin. She lives in Arkansas.

Learn more about this author