The earthworms that we find in our garden are not the best suited for vermicomposting as these are soil dwelling species. Red wigglers are a popular choice for vermicomposting. The worms for this project were bought online and are a mix of three composting specific species Eisenia fetida, Eisenia hortensis, and Perionyx excavatus.
The worms have working condition between 45-86 degrees Fahrenheit and require moisture levels between 60-90 %
Worms can eat half or even more of their bodyweight in food each day. If there is adequate food and space the population can double every three months. So If you start with 4 lbs of worms in 6 months you could have 16 lbs of worms all working to produce compost for you!
Setting up the bin:
To Start the flow through vermicomposter lay a single sheet layer of newspaper or thin straw directly on the bottom. Then the bedding can be added. The bedding can be anything from coco fiber, shredded newspaper, shredded cardboard, junk mail, straw or leaves. (Figure 23) Different bedding materials have different water holding properties and depending on the worms food source you may have to experiment with bedding and food ratios. Fill the unit with a mixture of bedding and food material and introduce your worms.( Figure 24-25)
How many worms do I need?
Other flow through vermicomposting units have reported worm optimal worm density at about 2 lbs per ft. You can certainly stock the unit with this many worms but it may be best to start with a small population and allow it to grow it its natural carrying capacity.
What can I put in the bin?
Worms can process almost any organic matter. Animal waste, food waste, paper, brewery waste, grape marc and other agricultural waste. There are a few things that should not be added, citrus rinds because of their high acid content, meat and dairy products as these often turn rancid and attract unwanted pests before the worms can break them down.
When adding waste it is best if it has been traditionally hot composted first. When organic waste it piled up it begins to break down and this process generates a lot of heat. When a large amount of waste is added at once to a worm bin it begins to heat up and this heat can kill the worms. So best results can be achieved by pre composing the bulk of the waste you feed the worms and only add raw uncomposted things in amounts that don't raise the internal temperature too high.
After 60 days from first loading the bin you can begin to start harvesting your castings. Pull one of the levers on the side of the unit. Only one pass of the scraper bar is sufficient to harvest. This will pull the scraper bar across the bottom and cause worm castings for fall out the bottom. You can then collect the castings. If you find a few or two just toss them back on top the bin.
After you reached this point you can harvest the castings weekly. Keep adding a thin layer of food on the top each week and you can keep scraping castings from the bottom.
For great resources about caring for worms, vermicomposting and science behind using worms castings check out.
Worms Eat My Garbage: How to Setup and Maintain a Worm Composting System Revised and expanded second edition Edition
by Mary Appelhof
Vermiculture Technology: Earthworms, Organic Wastes, and Environmental Management 0th Edition
by Clive A. Edwards (Editor), Norman Q. Arancon (Editor), Rhonda L. Sherman (Editor)