According to Brenda Sherman, of the North Carolina Cooperative Extension Service, using worms to decompose food waste offers several advantages:
It reduces household garbage disposal costs;
It produces less odor and attracts fewer pests than putting food wastes into a garbage container, or than traditional compost piles;
It saves the water and electricity that kitchen sink garbage disposal units consume;
It produces a free, high-quality soil amendment (compost);
It requires little space, labor, or maintenance;
It spawns free worms for fishing.
Equipment and Supplies for four to six people (about 6 pounds of waste per week)
Worm Bin
A 2-foot-by-3- foot plastic storage bin.
For aeration, drill three ½-inch holes on each wide side, spaced 5 inches apart.
For drainage, drill six ¼-inch holes in the bottom of the bin.
Plastic tray (or additional lid) - place under the worm bin to collect any moisture that may seep out.
Bedding
9 to 14 pounds of bedding (enough to fill bin about half full when moist). Use any combination of:
shredded paper (such as black-and-white newspapers, paper bags, computer paper, or cardboard);
composted animal manure (cow, horse, or rabbit);
finished compost
peat moss (which increases moisture retention);
Do not use glossy paper or magazines.
Handful of soil.
Water
3 pints of water for each pound of bedding.
If the bedding dries out, use a plant mister to spray some water on it.
Worms
1-2 pounds (~1000 worms per pound) of redworms or "wigglers" (Eisenia foetida) - (do not use night crawlers or other types of worms). Purchase from an online or local worm vendor.
Food
Organic waste including vegetables, fruits, eggshells, tea bags, coffee grounds, paper coffee filters, and shredded garden waste.
Worms especially like cantaloupe, watermelon, and pumpkin. Limit the amount of citrus fruits that you add to the bin to prevent it from becoming too acidic.
Break or cut food scraps into small pieces so they break down easier.
Do not add meat scraps or bones, fish, greasy or oily foods, fat, tobacco, or pet or human manure.
Cover the food scraps completely with the bedding to discourage fruit flies and molds.
Temperature
Redworms will tolerate temperatures from 50° to 84°F, but 55° to 77°F is ideal. Directions
Select a location for the worm bin.
Popular indoor spots are the kitchen, pantry, bathroom, mud room, laundry room, or basement.
Prepare the bedding.
Put shredded materials in a bucket of water and soak for 10 minutes. Wring it out like a sponge and fluff it up as you add the newspaper to your worm bin. Aim for the bedding to be very damp, but not soaking wet (only two to three drops of water should come out when you squeeze the bedding material). Spread the bedding evenly until it fills about half to three-quarters of the bin.
Sprinkle a handful or two of soil (from outdoors or potting soil) into the bedding to introduce beneficial microorganisms and aid the worms' digestive process.
Gently place your worms on top of the bedding. Leave the bin lid off for a while so the worms will burrow into the bedding, away from the light. The worms will not try to crawl out of the bin if there is light overhead.
Feed
Dig a hole in the bedding (or pull the bedding aside), place the food scraps in the hole, and cover it with 2 inches of bedding.
Wait until food scraps are eaten before adding more.
Bury food scraps in a different area of the bin each time. Worms may be fed any time of the day.
Maintenance
Fluff up the bedding about once a week so the worms can get plenty of air and freedom of movement.
Worms will eat the bedding, so you will need to add more within a few months.
Add water to maintain moisture like that of a wrung-out sponge.
Add food as needed. One pound of worms will eat about four pounds of food scraps a week. If you add more food than your worms can handle, anaerobic conditions will set in and cause odor. This should dissipate shortly if you stop adding food for a while.
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| Worm Castings |
Worm castings (soil-like material that has moved through the worms' digestive tracts) will be visible after about six weeks. After three or four months, it will be time to harvest the vermicompost, which consists of the castings along with partially decomposed bedding and food scraps. Vermicompost can be harvested by one of two methods:
Method 1: Place food scraps on only one side of the worm bin for several weeks, and most of the worms will migrate to that side of the bin. Remove the vermicompost from the other side of the bin, and add fresh bedding. Repeat this process on the second side of the bin. After both sides are harvested, resume adding food scraps to both sides of the bin.
Method 2: Empty the contents of your worm bin onto a plastic sheet where there is strong sunlight or artificial light. Wait 20-30 minutes, then scrape off the top layer of vermicompost. Scrape off the top layer of compost every 20 minutes or so, as worms keep moving down away from the light. Pick up the worms and gently return them to the bin in fresh bedding.
Be on the lookout for worm eggs; they are lemon-shaped and about the size of a match head, with a shiny appearance, and light-brownish color. The eggs contain between two and twenty baby worms. Place the eggs back inside your bin so they can hatch and thrive in your bin system.
Using Worm Compost
You can either use your vermicompost immediately or store it and use it later.
For more details, along with troubleshooting information, consult the excellent resources provided by Rhonda Sherman at http://www.bae.ncsu.edu/topic/vermicomposting/pubs/ag473-18.html.