Worm composting can be a wonderful solution for reducing household waste in places where a backyard compost bin may not be practical: An apartment, a school classroom or an office building. Worm bins are quite small and don't require contact with the soil, which means they can be kept inside or on a patio.
With the proper care and attention, the worms will thrive and help you reduce your waste while making a great fertilizer for your plants.
There are many types of worm bin systems available for purchase or you can build your own.
An easy and inexpensive option for a home-made worm bin involves using Rubbermaid totes. They come in a variety of shapes and sizes and last a long time.
Generally each square foot of surface area will support 1lb of worms, which will eat half their weight every day. A 53 L Bin (about 2 square feet of surface area) will support 2lbs of worms which will each 1lb of food a day (7lbs a week). A shallow bin is better than a deep bin.
An opaque bin will work best as worms don't like the light. Buy two of the same size bin so you can nest them together to create a sealed drip tray (See Diagram below).
Drill holes in the bottom of the top bin so that any liquid can drain into the second bin. This can be emptied once a month or so. You'll only need one lid. Drill holes in the lid for air circulation. Holes should be about 1/2cm in diameter.
The bin requires a few things before it is ready for the worms:
Now you're ready for the worms!
You need red wiggler worms. They are a special type of worm that likes to live right in their food and will do well in a bin. Dig your own from a friends compost bin or your local stable's manure pile. (Do not get worms from the soil - they're not the right type of worms). You'll need about 1/2 lb to start (and they will reproduce to fill the bin).
Worms bins work best if fed once a week, so save up your food scraps in a container on your counter (or in your fridge during warmer months) rather than putting them in the bin every day.
As the worms can take awhile to eat the food scraps you put in the bin, it's best to add the scraps to a different location in the bin each week. Consider using a popsicle stick to keep track of the last location you fed and working your way around the bin in a clockwise fashion. Add food scraps by pulling aside some of the bedding, dumping in the food and then covering the scraps with the bedding.
|√ Fruit and Vegetable Peelings||X Meat, Bones and Dairy (can lead to bad odours)|
|√ Moldy or Bruised Fruits and Vegetables||X Citrus|
|√ Egg Shells||X A lot of coffee grounds (can lead to acidic conditions)|
|√ Coffee Grounds, Tea Bags||X Strongly flavoured foods such as garlic or hot peppers|
|√ Dryer Lint, Human or Animal Hair||X Pet feces|
It's best to harvest the bin before it gets full and when there is little or no original bedding visible. Usually between 3 - 6 months after starting or harvesting.
Push everything over to one side of the bin and add new bedding to the the empty side (see picture to right). By only feeding the new side, you'll encourage the worms to move out of the finished compost, allowing you to scoop it out as needed (can take about 1 month).
Remove and set aside the top unfinished bedding. Shine a light on the finished compost. This will encourage the worms to move deeper into the bin, allowing you to skim off the top layer. Repeat as many times as necessary to remove finished compost. Replace the top bedding and feed as normal.
Dump the bin out on to a tarp and manually separate the worms from the finished compost. Remember to place the small, lemon-shaped worm cocoons back in the bin. Create small compost piles out in the sunshine to encourage the worms to move to the bottom of the piles and allow you to scrape off the top of the piles.