All you need to compost is a bin, some bedding, redworms, and garbage. Your worms will need a well ventilated, moist, dark, warm home where they can live and work. Before getting started, take some time to familiarize yourself with the essentials of vermicomposting:
Worm composting takes place in a bin that you can either buy or make yourself. A worm-composting bin should be shallow, yet wide enough to allow you to:
- bury food waste in many locations
- ensure the worms get enough oxygen
Ideally, the bin should be between 8 to 18 inches deep with the dimensions wider rather than deep. The size of your bin depends on how much food waste your household produces. A general rule of thumb is that you’ll need one square foot of surface area for each pound of waste produced per week. A household of two will need about 4 square feet of area.
Composting bins can be made from plastic storage bins, built from wood, or recycled from an old wooden drawer, wash tub, etc. Since worms need air to breathe, plastic or metal bins must have holes drilled in the cover and sides. Holes should also be drilled in the bottom of the bin to allow for drainage; ¼” holes at 15 holes per square foot. The bin can be placed in a waterproof container or on a tray to catch the excess drainage to make worm tea. An under-the-bed storage bin with casters works very well.
Worm bins are also manufactured and sold commercially—we carry the Vermihut Worm Bin in our shop. If using plastic, always wash the inside first and allow it to air out for a few days.
Initially, the bin is lined with a layer of bedding. This is where the worms will live. Food waste also needs to be fully buried in bedding. Shredded newspaper (black & white only) has always been a convenient and popular bedding material. Other bedding materials can include:
- shredded cardboard or printer paper
- yard waste (such as mulched leaves and grass clippings)
- cut up straw
- cut up hay
Worms need their bedding to be light, fluffy, and most of all MOIST. A handful or two of soil should also be added to the bedding to supply grit which will aid in the worms’ digestive processes and introduce helpful digestive microorganisms into the bin.
For worm composting to succeed, it is necessary to use redworms, also known as red wigglers. Redworms reproduce quickly, eat large amounts of food, and stay in the bin. These worms will move through the compost bin as they eat the food and bedding, creating compost and worm tea.
Redworms are sold by the pound (about 1,000 worms). They eat their weight in food every two days, so two pounds of worms will eat one pound of food per day. The worms will multiply every few months, eating more and making more vermicompost.
You can learn more about redworms in our Redworm FAQ section.
Worms like a vegetarian diet. They will eat any vegetable or fruit waste. Do not include any meat, egg, or dairy products (slow decomposition, odor problems) or foods high in oils, fats, salts, or vinegar. Citrus rinds can be added but only with equal portions of green leafy scraps in order to keep the pH level balanced in the bin. Eggshells (not eggs!) are also good for balancing pH.
- fruit & vegetable scraps & peels
- coffee grounds (filter paper included)
- tea bags
- crushed eggshells
- pasta & rice
- bread & cereal
- house plant clippings & dead flowers
- shredded paper – paper towels, napkins
HOW TO: INDOOR VERMICOMPOSTING
No matter where you live, you can vermicompost year round by composting indoors! Be sure to familiarize yourself with the basics of vermicomposting before you begin. Refer to our troubleshooting section to learn about common concerns, and remember that you’re always welcome to contact us with questions.
Obtain bin and order worms. Have your bin ready and waiting with moist bedding when your worms arrive.
Fill the bin with bedding. Worms need a home that contains about 75% moisture: add 3 pints of water to every pound of bedding. Continue to add bedding and water until you have about 5 to 7 inches of wet, but fluffed up, bedding. The bedding should be as damp as a moist sponge that if squeezed very hard would give a drop or two of water. Let the prepared bedding sit for 1 to 2 hours before adding the worms so that the water will reach room temperature.
Spread the worms over the top of the bedding. The worms don’t like light, so they’ll move down into the bedding. Leave the lid off and a light on overnight so the worms can settle in and become accustomed to their new home.
Place your worm bin in a convenient but somewhat out of the way spot, such as a basement, a mudroom, or under the kitchen sink. Redworms do well in temperatures between 50 and 80 degrees Fahrenheit. Some garages, unheated outbuildings, and outdoor locations can be used seasonally in New England locations (as long as they don’t get too hot).
After the worms have been in their bedding for a day or two, begin feeding them by burying food waste that decays relatively quickly, e.g. banana peels, spaghetti noodles. Bury food in the bedding every few days but at least once a week. Dig a hole in the bedding, place the food, and cover it with bedding. Pick a new spot each time you feed them.
If the bedding dries out, mist it with water from a spray bottle.
Within four to six months, most of the bedding and food waste will have been converted into a finished compost product (vermicompost) which is uniformly dark and soil-like. At this point, harvest the vermicompost and provide the worms with fresh bedding.
To separate the worms from the compost you can:
1. Move all of the finished compost to one side of the bin, then add fresh bedding to the empty side. Begin feeding the worms in the fresh bedding, and within a month most of them will have moved over to the clean side. Now you can remove the finished compost and replace it with fresh bedding.
2. Dump your finished compost into a pile, shaped like a pyramid, and place a bright light over it. The worms, repelled by light, will move down into the compost leaving the top layer worm-free. You can remove the compost from the top of the pile and repeat the process until you have nothing but worms and a little compost left in your original pile. Place the worms in fresh bedding.
3. If you have a commercial composting bin with stacked trays (like the VermiHut), the worms will migrate up through the working trays on their own as you place fresh bedding and food for them!
HOW TO: OUTDOOR VERMICOMPOSTING
To get fast, super rich compost, use redworms in your outdoor compost pile. Keep in mind that redworms can only tolerate temperatures between 38°F and 88°F. Wait until the warm months to compost, and place the compost pile in a shaded location that won’t get too hot.
Dig a shallow hole in the middle of the outdoor pile. Deposit the worms in the hole along with their bedding and cover with plant wastes and/or aged manure. Keep the pile moist. The worms will seek out the area of the pile that is most comfortable for them and go to work!
Redworms eat their weight in organic matter every 2 days. (Two pounds of worms will eat one pound of waste per day.) When composting outdoors, figure about one pound of worms per 1/2 yard of compost and feed accordingly.
Redworms are prolific and will multiply every few months.