Worm composting allows homeowners and apartment dwellers to use the voracious appetite of compost worms to transform food scraps and kitchen waste into nutrient-rich humus. Familiarize yourself with the intricate relationship between worm composting and food to maximize your chances of experiencing success with your worm composting endeavor.
Careful food selection for worm composting plays an essential role in minimizing potential problems in your worm bin. Canada's Office of Urban Agriculture suggests sticking with mild food scraps, with possible choices including vegetable scraps, fruit waste, crushed eggshells, coffee grounds and even used tea bags, provided you first remove non-biodegradable materials, such as metal staples. According to Loren Nancarrow, coauthor of "The Worm Book," you should sprinkle gritty food materials, such as the crushed eggshells, across the surface of the shredded newspaper worm bedding once or twice weekly to help improve their rate of food digestion.
Compost worms generally need fresh food once or twice weekly. When you're ready to feed them, peel back several inches of bedding and gently place the food scraps in the hollowed-out area. Cover the food scraps with 3 to 4 inches of fresh, shredded newspaper bedding to keep bad food smells to a minimum. Depositing fresh food in a different area of the worm bin at each feeding helps prevent potentially problematic food buildup.
Compost worms consume food waste more quickly when their basic needs are met. Keep the worm bin bedding temperature between 55 and 77 degrees F to minimize stress levels and to obtain maximum food consumption, as recommended by Nancarrow. Checking the bedding moisture level daily to ensure that it stays about as wet as a wrung-out sponge is a key preventative strategy that helps ensure that the worms don't dry out. Proper worm-to-food ratios also help ensure that the worms have plenty of food to consume but not so much that the food sits in the worm bin for days before the worms can eat it. As a general rule of thumb, 2 lbs. of worms (approximately 2,000 individual worms) can consume approximately 1 lb. of food scraps each day.
Expect compost worms to take a minimum of 10 weeks to convert your food scraps into vermicompost, the nutrient-dense humus material that is the finished product of the worm composting process. Look for this vermicompost in the form of small chunks or clods of dirt-like material. As the 10-week deadline approaches, you should be able to see more and more of the chunks of earthy material. Once the vermicompost begins to take up more than approximately 2/3 of the worm bin bedding, shift it to one side of the bin. Add fresh bedding to the empty side of the bin so you can continue to provide your worms with plenty of fresh food scraps while you remove the finished vermicompost over the course of several days.
Never put extremely smelly or moldy food products in a worm compost bin, especially when using an indoor worm compost bin. Doing so may attract insect pests and lead to rodent problems. Specific foods that Canada's Office of Urban Agriculture suggests you avoid include dairy products, oily foods and meat products.