Experiencing issues with your worm bin? Don't give up! Many common challenges have simple solutions.
If the bin contents are too wet
Solution: Too much moisture will not allow the worms to breath and may create unpleasant odors. Visible mold could also be a sign of conditions that are too moist. If the bedding is wetter than a wrung-out sponge, add dry bedding to soak up excess moisture. You can also reduce the amount of moist food scraps you add.
If the bin contents are too dry
Solution: Consistent moisture is important to maintain a hospitable environment for the worms. If the bedding seems to be drier than a wrung-out sponge, sprinkle or mist with water, or add more moist food scraps.
If the bin has a bad odor
Solution: Make sure all food scraps are covered with bedding to prevent odor. Some foods are naturally odorous when decomposing (such as onions, broccoli, or cabbage). Remove foods that produce unpleasant odors if it bothers you. Don’t add meat, bones, dairy, or oil products. The bin may also smell if it is too wet or not getting enough air. In that case, aerate the bin by gently mixing some fresh, dry bedding into the contents of the bin.
If the food scraps are decomposing very slowly
Solution: Chop food into small pieces before feeding to the worms, especially tough materials such as stems. Also try freezing and thawing food scraps to soften them before adding. You may simply be overfeeding the worms. Try feeding the worms less, and wait to add more food until the previous batch is gone.
If the bin is attracting fruit flies
Solution: Fruit can be microwaved for 60 seconds or frozen to kill any fruit fly eggs before being fed to the worms. Bury fresh scraps under bedding when you add them to the bin to reduce odors that attract flies. Or, don't add any food scraps to the bin. If necessary, make a fruit fly trap by mixing apple cider vinegar and a dash of dish soap in a cup. Optionally, cover the cup with plastic wrap secured with a rubber band, and poke some small holes in the plastic wrap.
If the bin has mites
Solution: A small mite population is good, but if you notice large collections of mites you should try to remove them. Remove any food that has a congregation of mites. Add a few slices of melon (watermelon and cantaloupe work well) to the bin. Mites will congregate on the melon in a short period of time. When the slices are covered, remove, rinse off the mites, and then then return the melon slices to the bin and repeat until the population is reduced. You can also try placing a slice of fresh bread in the bin, waiting until mites congregate on it, and then removing the bread.
If the bin is attracting other pests
Solution: A small population of invertebrates indicates a healthy ecosystem in your bin. However, if other insects are swarming your bin, the only solution may be to harvest the worms (see above) and start fresh in a clean bin with new bedding and food scraps.
If the bin has few or no worms
Solution: If the conditions are not suitable, worms will die and decompose quickly, leaving you with few worms. Unsuitable conditions could be too wet, too dry, too hot, too cold, not enough air, or not enough food. The worm bin should be kept between 55 and 75 degrees Fahrenheit, should be not too wet or dry (see above), and should have air space in the bedding. If contents of your bin seem very compacted, add paper tubes or other bulky paper products such as torn up paper egg cartons to increase air flow. Worms can last a while without being fed, but make sure not to let too much time pass between feedings.