It doesn’t happen often, but, indoor worm bins can experience “catastrophic failure”. Our policy at NATURE’S PERFECT PLANT FOOD is; “we’ll replace your worms once.” We’ve only done this three times in five years and considering we have sold starter kits to hundreds of people, almost all indoor bins do just fine. The primary culprit behind a sudden bin die off or “live worm vanishing” is poison. Keeping an indoor vermicomposting bin is in many ways like having an aquarium. Both need a healthy bacterial balance, consistent environmental conditions and food/waste management. You are in essence maintaining a tiny eco-system.
Poisons come in many forms, one unfortunate “worm replacement” was the direct result of a common household cleaning product, another from the introduction of pesticide treated plant material. Just as you wouldn’t feed your fish poisonous foods, be aware of your worm bin input, including bedding material. Nature herself supplies many protections for her children, worms will attempt to flee a poisonous habitat, keep an eye on your bin. Another common bin poisoning results from an increase in anaerobic or “bad” bacteria, this type of decomposition is characterized by a foul oder and can happen quite quickly. Again, keep a nose on your bins, healthy bins smell good, like the soil after a nice rain. Take note of the moisture content in your bin, too much and anaerobic action will occur. To little and the worms will dehydrate and ultimately the colony will fail.
All in all, red worms are a hearty bunch, check your bin every couple of days, watch for signs of distress. When worms begin to attempt escape there’s something off-balance. Here are some hint for trouble shooting… http://www.naturesperfectplantfood.com/2012/03/14/trouble-shooting-indoor-worm-bins/