From rotting potatoes to moldy banana peels, organic waste in an indoor compost bin may create potent odors that can cause you and your house guests to wrinkle your noses in disgust and head for the door. Although indoor worm composting is more convenient than traditional outdoor composting methods, a poorly managed bin quickly develops odor problems and may even kill off your compost worms. According to Loren Nancarrow, the resulting odors often attract a wide range of pests, including flies, ants and mice, that will beat a path to your door in search of the aromatic waste languishing in your worm bin. Monitor your worm bin carefully to catch potential odor problems before they become major issues.
Practice preventative feeding habits. Limit the food that you give your worms to mild fruit and vegetable waste, such as melons, banana peels, potato scraps and carrot peelings. Never put partially decomposed food scraps or hard-to-decompose waste, such as meat, dairy products or fatty and oily foods in the bin. Crush eggshells to a fine powder with a rolling pin; sprinkle them into your bin to provide grit, which allows your worms to process food waste more quickly, according to Nancarrow.
Check the amount of food your worms consume so you're aware of how much waste your worm population can handle in a single day. Pull back the top several inches of bedding to see if old food scraps are still present in the bin. Do not add any more food scraps until the waste already in the bin is almost gone.
Monitor the moisture level in your worm bin. Excessive dampness leads to smelly, anaerobic decomposition, so make sure the bedding is about as damp as a wrung-out sponge. Add an extra two- to three-inch layer of fresh shredded newspaper bedding to the top of your bin to soak up any extra moisture, if necessary. Mix the new bedding with the old bedding to increase aeration.
Drill extra ventilation holes in your worm bin to help balance the moisture and oxygen levels in the bin, especially if your bin is plastic. Use a quarter-inch drill bit to make a row of ventilation holes around the entire circumference of the bin. Locate the holes about three inches from the top edge of the bin and space them in two-inch intervals. Place the lid loosely on top of the bin to promote additional ventilation.