Composting Worms Supercharge Your Plant's Health

The information on this page will teach you about the basics of keeping composting worms. You'll learn everything from how to set up your first bin to how to brew worm tea.

Move over sliced bread!

Composting worms are all the rage, and it looks like they're here to stay. Join us, and find out why this wiggling phenomena is becoming so popular. Who knows? Composting with worms may just revolutionize waste management.

If you're a teacher or have kids, you're going to love this page. Using worms to compost your food waste is an incredible way to teach children about composting. It's also a great way to start composting at home.

Learning to Compost With Worms

Before we get started, please note that there are several different terms to describe composting with worms, including vermiculture and vermi-composting.

All of these terms describe the controlled process of using worms, namely red wigglers (Eisenia foetida), to decompose organic waste, such as kitchen scraps, coffee grounds, and manure. After these wastes are broken down, the finished product, or worm castings, are harvested and used as nutrient-rich soil amendments.

These processes can take place in large-scale commercial vermiculture facilities, however, we are going to focus our discussion on the small-scale home vermiculturist, better known as YOU!

We're going to teach you all about composting with worms, including:

So what are you waiting for? Let's start wormin'.

Why Compost with Worms?

There are a lot of different reasons why people compost with worms. For instance, we started because we juice a lot of vegetables, and couldn't stand to throw all of that wonderful pulp into our regular compost bin. Because this waste was already pre-digested, we knew worms would have to do very little work to make use of it. Aside from that, we started indoor composting with worms because we live in Ontario, Canada, and our outdoor temperatures don't allow for quick composting in the winter months (November-March). Now that we use an indoor compost bin, we're able to produce organic fertilizer all year round.

Other reasons to start worm composting include the following:

Here is a great story about one of our Tribe members and her incredible worm composting bins.

What You Need to Know to Get Started

Using composting worms is very easy. Below are some basic vermiculture guidelines to consider before you start your wormy adventures.

4 Things You Will Need

1. Worm Bin

A worm bin, or worm container, can be homemade or purchased from a worm bin supplier. We prefer the homemade varieties because they tend to have more character. Also, nothing says compost junkie, like re-using scrap materials to make a new worm bin.

The 3 factors that need to be considered when building, or buying, a worm bin are the shape, size, and materials. You must also consider where you will put your worm bin.

Remember, worms need lots of oxygen, so whatever bin you choose, please make sure it has adequate ventilation. Also, the rule of thumb for bin size is two square feet of surface area per person, or one square foot of surface area per pound of food waste per week.

Update - March 2012

We no longer recommend using plastic bins for your worms. Find out why - Ixnay Your Plastic Worm Composting System.

Below is an image of a worm composting bag, created by Amy, a fellow compost junkie. These bags are wonderful creations that minimize the work needed to harvest worm castings. Food is added to the top of the bag, which keeps the worms near the surface, while worm castings are harvested from the bottom of the bag. Ingenious? We think so. Excellent work Amy.

If you're interested in building your own worm composting bag, here is a list of step-by-step instructions.

worm composting bin-bag

2. Bedding

The most common bedding materials for composting worms, include shredded newspaper or computer paper, leaf mold, peat moss, animal manures, coconut fiber (coir), and wood chips.

Each of these bedding materials has its own list of advantages and disadvantages. For instance, leaf mold is a natural habitat for worms, but it may also contain organisms that you don't want in your worm composting bins.

It doesn't matter which bedding material(s) you choose, you must always remember to add a couple handfuls of soil, or rock dust, to your worm bin. This is especially important if you are just setting up a new bin. These ingredients add "grit" to the bedding materials in your bin. This grit is very important because your worms use it in their gizzards to help in breaking down food particles. The soil has the added benefit of inoculating your bin with various soil microbes, all of which are important in establishing a healthy ecosystem for your composting worms.

3. Worms

Ah, it's finally time to discuss the workforce within your bin...your worms!

Unfortunately, you can't just use any old earthworm in your worm bin. The common earthworms that you see in your garden, and those that are on the pavement during rain storms, are typically a burrowing-type of worm. In a bin, we are in need of worms for composting that are surface-dwelling, and that's why we typically use red wigglers. If you're interested, here is a more complete history of the earthworm, including how it made it's way to North America.

The Almighty Red Wiggler is the most common type of worm used in vermiculture systems. Other types, such as blue-worms (Perionyx excavatus), are better able to withstand warmer temperatures, so they are used in more tropical regions.

How many worms do you need?

Composting red worms are typically sold by weight, rather than by number. So if you see a quantity of worms listed by your worm supplier, please know that this is just an estimate. It would be quite hard for your supplier to make any money, if they spent their entire day counting worms.

3 factors to consider when determining the number of worms you need to purchase are:

  • the size of your bin
  • the amount of money you want to spend, and the price of the worms
  • the amount of food waste you'll be adding to your bin each day

For a typical-sized worm bin (surface area = 2'x2'), being used by an average-sized family (3-4 people), we suggest you start with a minimum of one pound of worms. A pound of worms will usually cost between $30-$50 (including shipping). Always remember, with time, your one pound of worms will quickly grow into two pounds, if your bin is maintained properly and your worms are well fed. You will eventually want about one pound of worms per cubic foot of volume in your bin.


buy composting wormsBuy Worms!

The best place to buy worms for composting is online from compostjunkie.com. We work hard to bring you the healthiest worms at the best prices.

Click on the image of the worms to the right and it will take you to our store, where you'll be able to purchase your composting worms.


4. Food

It is very important to ensure you are not over-feeding your composting worms. If you are new to the composting-worms scene, we suggest you start by monitoring your feedings very carefully. This means that you'll have to start by feeding smaller amounts of food. By feeding smaller amounts, you will quickly get a good idea as to how much food your given quantity of worms can handle.

A worm can consume more than its weight each day. If you start with roughly a pound of worms in your bin, expect to be able to feed them at least one pound of waste each day.

Below is a short list of foods to feed your composting worms. Also, it is highly recommended that you mix in a high quality source of calcium to your worm food. We like to use ground up eggshells.

Do Feed Avoid/Limit
rice citrus
fruit scraps meat
vegetable scraps bones
coffee grounds garlic
pasta hair
tea leaves and bags dairy

Update Feb 2012 - As much as we previously said to avoid feeding your worms the above food items, the reality is that a well established worm bin can handle almost any carbon-based ingredients (including all of the above). That being said, please use moderation when feeding these items to your worms...don't overdue it. If you have doubts, avoid these foods altogether and stick to the basics of what works.

Moisture, Temperature, Aeration, and pH

As it is with all of our composting ventures (outdoor composting bins, composting toilets, compost tumblers), to successfully compost with worms, you must ensure the conditions are right. When using composting worms, you want to ensure you have the right moisture, temperature, aeration, and pH levels. To learn more about each of these factors, please click on the corresponding term.

Here is an example of what can happen when you have too much moisture in your bin and the pH becomes too acidic - You may get white worms.

Harvesting

Traditionally, there are two methods used to harvest composting worms from worm composting bins. The first method is referred to as the low maintenance harvest, and the second method is referred to as the medium to high maintenance harvest. Below is a small definition of each. If you'd like more information about these specific harvesting techniques, please refer to our harvesting composting worms page.

    Low Maintenance Harvest - This method has two phases: the feeding and phase and the fasting phase. During the feeding phase, you feed your worms for a period of three to four months. This is followed by the fasting phase; during which time, you do not feed any food for three to four months. During the feeding phase, your worm population grows and starts to consume the food. During the fasting phase, your worm population peaks and eventually dwindles to nothing (when all food supplies are exhausted). At this time, you can easily harvest all of the worm castings from your bin. Unfortunately, following this method means that you will have to purchase new worms every six to eight months.

    worm compost bin

    Medium to High Maintenance Harvest -
    How you use this method to harvest composting worms will all depend on the design of your specific worm bin. Some bins require that you dump your bin out and sort the composting worms by hand; whereas, other bins allow the worms to do all the sorting. An example of a bin design that allows the worms to do all of the sorting, can be seen to the right. To learn more about all types of worm bins, please visit our worm bin page.

Worm Castings
Supercharge Your Plant's Health

Worm castings, or vermi-castings, are the more technical terms used to describe the poop of composting worms.

We often think of worms consuming soil and decaying organic matter; however, they are actually going after the bacteria, and other microbes, present on the surfaces of these substances.

Another interesting fact about a worm's digestion - It is not the worm's own enzymes that breakdown the substances it consumes. Instead, these substances are broken down, and processed, by the bacteria present in the worm's intestine.

So how does all this fit into the health of your plants?

Since a worm's gut is dominated by bacteria, the vermi-castings it produces are also dominated by bacteria. If you refer back to our page on compost tea, you will recall that specific plants thrive in more bacterial-dominated soils (compared to balanced, or fungal-dominated soils). For instance, annual plants, including vegetables and flowers, love bacterial dominated soils. So we can assume that they'll welcome an application of worm castings. However, worm castings are quite potent, so you must make sure you use them properly.

For more detailed information about the use of worm castings as a soil amendment, please visit out worm-casting page.

Worm Tea
Use it to Brew a Better Compost Tea

We are NOT using the term, worm tea, to describe the liquid that percolates out of your worm bin. We refer to the liquid that drips out of your worm bin as worm leachate. We do not recommend that you use worm leachate directly on your plants, or directly as a soil conditioner. The reason being - worm leachate contains a number of partially decomposed substances, some of which have the potential to be phytotoxic (i.e. harmful to plants).

If you want to use this worm leachate, we suggest you dilute it with water (preferably distilled), and apply it to the soil around your plants. Try to avoid using this mixture as a foliar spray. If your worm composting bins are fairly mature, you will probably see some benefit.

What do we mean when we say worm tea?

We are referring to the tea produced when you substitute, all or some, of the compost in compost tea with worm castings. This mixture will then be actively aerated and fed, just like a regular batch of compost tea. But don't forget, worm castings are bacterial-dominated, so be sure you take that into consideration before you brew your tea.

If you would like to learn more about worm tea (including great worm tea recipes) and worm leachate, please visit our page dedicated to worm tea.


compost worms book

Worm Composting
Books and Links

If you're still looking for more information about composting worms, we've got one last page for you - our books and links page.

On this page, we have compiled a list of incredible worm composting books, including Worms Eat My Garbage by Mary Appelhof. Since we've read all of these books, we've
also added our reviews to this page. Finally, you'll find
a number of links to other great composting worms sites.

Have A Question About Composting Worms?

If you have a question about composting worms, please ask us.

What Other Visitors Have Asked

Click below to see questions from other visitors to this page...

Vacationing with Worms - What Should I Do? 
Could you please tell me what bulk food I could buy for my worms as I'm going to be away for 2 months and need to leave food for them. My friend has chooks …

Worm Composting Bins and Ideal Temperatures 
I plan to start a small worm composting bin and would like to know the best place to put it based on the temperatures outside. What can the worms withstand …

Why Do We Have Fruit Flies in Our Worm Bin? 
We have been trying to vermicompost for months now but we keep getting fruit flies in our bin. It's cold where we are in the winter so I'm not sure the …

Can I Feed My Worms Colored Newspaper? 
Hi Dave, I love the 4-part interview and what you are doing. My question, and you’ve probably heard this many times over. Our newspaper is mostly color …

Mites in My Worm Bin 
I found gold coloured mites in my worm bin. I only feed the worms mulched up veggie waste and shredded paper and cardboard but these little critters are …

What Temperature is Your Worm Bin? 
My university started a worm composting bin this semester. Everything appeared to be working well, we had lots of worm castings and tea. Then something …

Can I Re-Use My Bag of Worm Castings When Making Tea Compost? 
I am new to making compost tea , but everything seems to be going well. I am using a 5 gallon bucket, an aquarium pump with 2 air stones, an old pantyhose …

Is Worm Composting In a Bathtub a Good Idea? 
Is it advisable to use an old bathtub as a worm composting bin? If so, what is the best way to aerate the tub? We have one to use, but are concerned about …

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