Worm Composting Tutorial

How to make a Worm Bin


1. Get a suitable container (wide and shallow) and drill ventilation holes in it.

2. Make a bedding. Newspaper of shredded paper wrks great for this. Just tear the paper into strips, moisten it so it’s the moisture of a wrung our sponge, and fill the bottom six inches of your bin.

3. Spread your worms on the top of the bedding.

4. Add food.

5. Add more bedding to cover food (3-6 inches).

Vermicompost is the use of worms to digest organic matter. They eat food scraps and excrete worm castings, a dark crumbly substance we call Black Gold! Vermicompost is a more concentrated and rich fertilizer than ordinary compost, and it greatly improves the health of soil and plants. By creating vermicompost systems, we can easily turn food scraps into valuable resources rather than sending them to a landfill.

Red worms, also called red wrigglers, and are best suited for the job. This is because they eat large quantities of organic material and can digest up to their body weight every day. Unlike night crawlers and other common earthworms, they can thrive in the confined space and environment of a worm bin. The species Eisenia foetida and Lumbricus rubellus are most commonly used. Worms have no eyes, and they move through the soil with the help of a feeling pad or prostomium. They don’t have teeth either, so a little dirt in the gizzard helps grind up their food. Worms are hermaphroditic (having both ovaries and testes) and can reproduce at about 6 weeks of age. They join together via mucus secretions and both deposit sperm onto the other worm. A cocoon then forms over the clittelum, collecting both eggs and sperm as it slides off the worm’s body. After a two to three weeks, baby worms hatch from the cocoon!

There are many options, from a homemade wooden box to a plastic tub or commercial bin. The container should be wide and shallow, because red worms are surface feeders. It should have plenty of holes for ventilation, and possibly for drainage as well. The following are important things to consider when setting up a bin:

Surface Area
How much material do you want to compost? The more surface area, the more food you can add. There should be about 1 square foot surface area for every pound of material per week. But this is just an estimate; it’s fine to experiment and have a bigger bin with plenty of space. The worms will adjust their population to whatever size bin you provide.

It’s fine to keep a worm bin indoors. If managed properly, there won’t be any problem with odors, flies, etc! Indoor worms are much happier during the cold winter months, and they’re more likely to survive and keep reproducing. You can keep a bin under the kitchen sink, in a pantry, or mostly any place that’s convenient for you. If you keep your bin outdoors, it should be located on the north side of the house (away from direct sunlight). Keep it in the shade, protected from rainfall, and as insulated as possible during the winter.

Worms need a nice comfortable home, similar to their natural habitat. Bedding should be light and fluffy, so that air can flow through. It should also be moist, like a wrung-out sponge. Possible bedding materials are shredded newspaper (non-glossy), straw, or leaves. You should have about 6 inches of moist bedding at the bottom, and a nice thick layer of dry bedding on top, to cover and insulate the worms.

Worms hate light, are cold-blooded, and breathe through their wet skin. They like a dark, warm, moist environment! Optimal temperatures are 55-77* F. They need air and will drown if bedding gets too saturated. So holes for aeration and drainage are very important. Your goal is to create a 5-star worm hotel!

Worms eat a primarily vegan diet of fruits, veggies, and grains. They can eat coffee grinds and citrus, but only small amounts so it’s not too acidic. Meat and dairy contain pathogens and tend to produce strong odors, so don’t feed them to your worms! Experiment with how much food your worms can handle at a time they like it moldy, but if you find lots of VERY moldy smelly food piling up, then you’re probably overfeeding. If all the food is gone every time you check, probably feed more. Chopping small increases surface area, so they can eat it faster.
Yes: tea bags, coffee grounds, egg shells (ground up0, veggies, fruit, etc . . . No: citrus, meat, dairy .

Over a few months, the bedding volume will decrease. That’s because worms are eating and turning it into castings! This makes the environment less and less healthy for them, because there’s less air flow and because castings are toxic to them at high levels. If you wait until everything is entirely converted to castings, the worm population will be small and unhealthy. But if you harvest the castings sooner, you can give the worms a fresh start with new bedding and start over with a large, robust population. This means you’ll have to SORT the vermicompost. There are two basic ways to do this.
-One Time Method: Empty your worm bin onto a plastic tarp. Make mound shape piles 3-5 in diameter. When the piles are exposed to light, the worms will migrate to the bottom of the pile, allowing you to remove the compost on the top of each pile. At the bottom of each pile will be a “cake” of worms. These can be placed back in the refurbished worm bin! -Continuous Method: Let the worms sort for you. Just feed your worms on one side of the bin for a month. The worms will migrate to the side with the food, and the worm castings on the other side can be easily removed! Worm compost is a great source of nutrients for plants, and it also improves the structure and water-holding capacity of the soil. You can sprinkle the compost onto garden beds, In seed flats, or even potted plants indoors.

Sources of Red Worms:
Project Compost projectcompost@gmail.com
Easy Crawler Worm Farm in Dunnigan, Yolo County (530) 908-0744
Sonoma County Worm Farm (800) 447-6996
Yates Sporting Goods in Davis (worms sold as fishing bait)
ACE Garden Supply sells red worms in March/April only!
You can find them in near-finished compost piles!
For other suppliers, see www.ciwmb.ca.gov/organics/worms/wrmsuply.htm